Tag Archives: influenza

Discovery of a new target promises a long-lasting, universal flu vaccine

An international research effort might finally lead us to a universal, long-lasting flu vaccine.

Image via Pixabay.

Influenza, or ‘the flu’, is one of the most persistent viruses that humanity has contended with throughout history. Although several vaccines against the flu have been developed and deployed year after year, the virus’ high rate of mutation means that it often bypasses our bodies’ immunity. It also leads to a huge number of influenza strains, often quite different from one another, making it hard for a single vaccine to provide immunity against all of them at the same time.

So far, we’ve been unable to develop a single, long-lasting, and broadly-acting vaccine against the flu. However, new research might change this.

Targeting the anchor

“It’s always very exciting to discover a new site of vulnerability on a virus because it paves the way for rational vaccine design,” says co-senior author Andrew Ward, PhD, professor of Integrative Structural and Computational Biology at Scripps Research. “It also demonstrates that despite all the years and effort of influenza vaccine research there are still new things to discover.”

The findings come from a combined effort of researchers at Scripps Research, University of Chicago and Icahn School of Medicine at Mount Sinai. Their work revealed a previously-unknown vulnerability of the influenza virus — a section that is very stable across time and strains (i.e. it doesn’t mutate almost at all) which the team dubs ‘the HA anchor’.

Since this anchor is common among strains and doesn’t change over time, a vaccine designed to interact with this anchor will be effective across strains and over the years, despite the virus’ propensity to mutate.

“By identifying sites of vulnerability to antibodies that are shared by large numbers of variant influenza strains we can design vaccines that are less affected by viral mutations,” says study co-senior author Patrick Wilson, MD. “The anchor antibodies we describe bind to such a site. The antibodies themselves can also be developed as drugs with broad therapeutic applications.”

On average, influenza infects over 20 million people and leads to 20,000 deaths in the United States alone — many more worldwide. Current vaccines target an area on the virus known as the head of hemagglutinin (HA), a protein that extends outwards from its shell. Although this area is easy to reach and highly reactive, which makes it a good target for our immune system, it’s also one of the most volatile parts of the virus, changing very rapidly. It’s the mutations of the HA that make it necessary for new influenza vaccines to be developed every year.

For the study, the team looked at 358 flu antibodies from the blood of people who had been either vaccinated with a seasonal influenza vaccine, universal influenza vaccine, or had been infected with the virus.

Many of the antibodies they analyzed were already known to science and targeted known areas of the virus. However, a few stood out — they had not previously been documented and tied to a new area. This led the team to discover the anchor. In total, 50 different antibodies from 21 individuals were identified tying to this area. Mouse studies in the lab showed that these antibodies were effective against three H1 influenza viruses.

“In order to increase our protection against these highly mutating viruses, we need to have as many tools as we can,” says Julianna Han, a staff scientist in the Ward lab and one of the paper’s co-first authors. “This discovery adds one more highly potent target to our repertoire.”

“The human immune system already has the ability to make antibodies to this epitope, so it’s just a matter of applying modern protein engineering methods to make a vaccine that can induce those antibodies in sufficient numbers,” adds Jenna Guthmiller, a postdoctoral fellow at the University of Chicago, the other co-first author.

The team is now working to design a vaccine that better targets the HA anchor of the virus.

The paper “Broadly neutralizing antibodies target a hemagglutinin anchor epitope” has been published in the journal Nature.

Pfizer begins human trials of an mRNA-based flu vaccine

Building on the success of their Covid-19 vaccine, the US pharmaceutical company Pfizer started a clinical trial to test an influenza vaccine using mRNA technology. The goal is to improve the currently used flu vaccines, which only have an efficacy of 40% to 60% against a disease that can cause up to 650,000 deaths per year.

Image credit: Flickr / The Focal Project

Pfizer dosed the first participants in a study to test the vaccine it developed with the German company BioNTech, the same one it worked with for its Covid-19 vaccine. The study, an early-stage Phase 1 clinical trial, will look at the safety, tolerability, and immunogenicity responses compared to another flu vaccine approved by the FDA. 

About 650 healthy adults aged 65 to 85 will be recruited in the US to participate in the study by Pfizer. The candidates will encode WHO recommended strains, which will be followed later by multivalent combinations. As the program progresses, strains could be updated based on recommendations for subsequent influenza seasons, Pfizer said.

Kathrin U. Jansen, Head of Vaccine Research and Development at Pfizer, said in a press statement that the company has been working since 2018 on a potential MRNA influenza vaccine. The pandemic provided an “immense scientific opportunity” for mRNA, especially considering the improved efficacy needed with flu shots, she added.

Moderna, the pharmaceutical company that also developed an mRNA vaccine for Covid-19, had already announced in July the start of an early-phase clinical trial. Back then, the US company had said that if the trials are successful, they will seek to bundle the vaccine with three other mRNA-based ones so as to have a yearly one-stop shot. 

The role of mRNA vaccines

Before the Covid-19 pandemic, mRNA vaccines were largely experimental — many researchers regarded them as “the next big thing in vaccines,” but they had not yet proven their worth. The impetus brought by the need for new vaccines led Moderna and Pfizer to develop two mRNA-based ones for SARS-CoV-2 in under a year. Now, they want to use this technology for other infectious diseases. 

Receiving an mRNA shot means being injected with bits of genetic materials from the target virus instead of the virus itself. Our cells then use that genetic information to learn how to build snippets of the virus that generate an immune response. It’s a highly-anticipated vaccination technology that could help to tackle several diseases. 

The fact that influenza vaccines have to be updated every year to match circulating strains, as well as the expensive and time-consuming production process, make the vaccines ideal candidates for replacement with mRNA technology – which only requires the genetic sequence of the virus and would be produced much faster. 

While not as threatening as Covid-19, the flu is still a big public health problem. It has affected between nine and 45 million people every year since 2010, according to the Center for Disease Control and Prevention. About 650,000 people are killed every year by it, according to the World Health Organization, also causing 5 million cases of severe illness. 

Influenza vaccine could also help against severe Covid-19 — but we’re not entirely sure why

The influenza vaccine could help attenuate the adverse effects of SARS-CoV-2 worldwide, according to a new study. Researchers found an 8% drop in hospitalization in Covid-19 positive patients receiving the flu shot, suggesting a benefit for populations struggling to get access to the coronavirus vaccination.

Image credit: Flickr / CAL OES.

The researchers from the University of Miami Milles School of Medicine explored about 75,000 digital medical files of patients from all around the world., especially in the United States and Europe. The study focused on the period before the worldwide rollout of the coronavirus vaccines.

Patients were sampled by age, gender and medical conditions, such as heart disease and diabetes. The researchers looked at the evolution of coronavirus symptoms in the next 30, 60, and 120 days from the time patients were diagnosed, looking for a correlation with the flu vaccine. 

The findings showed a statistical link between the risk of developing Covid-19 symptoms and non-vaccination against the flu, with ICU admissions being lower in patients who received the flu vaccine. Patients who received the influenza vaccine also experienced a decreased risk of sepsis and stroke.

“Even patients who have already received SARS-CoV-2 vaccination may stand to benefit given that the SARS-CoV-2 vaccine does not convey complete immunity, although further research into the relationship and potential interaction between influenza vaccination and SARS-CoV-2 vaccination should be performed,” the researchers wrote.

Influenza and Covid-19

In a study earlier this year, researchers found a potential protective effect of influenza vaccination against adverse outcomes associated with Covid-19. The finding showed a 2.44 greater odds ratio (OR) for hospitalization and 3.29 greater OR for intensive care unit admission on patients who weren’t up to date with their influenza vaccination. 

In fact, several studies have recently suggested a possible protective effect of the influenza vaccine against the novel coronavirus. Although researchers aren’t entirely sure what is offering the protection, they have a few theories.

Influenza and Covid-19 are both contagious respiratory illnesses but are caused by different viruses. While Covid-19 is caused by infection with a coronavirus (SARS-CoV-2), seasonal flu is caused by infection with one of the many influenza viruses that spread annually. Symptoms may be similar and that’s why it’s so important to get tested. 

Influenza is estimated to kill about 2 in every 100,000 people it infects, making it much less severe than the novel coronavirus, with so far 4.55 million deaths on a global scale. Some examples of the flu include the viruses H1N1, which caused the Swine Flu of 2009 and the Spanish Flue of 1918, and the H5N1, which also has pandemic potential. 

Although production and distribution of Covid-19 vaccines continue to increase daily, the fact remains that certain populations in the global community may still have to wait a long period of time before they are vaccinated. This is why researchers are now looking into the possible benefits of more comprehensive influenza vaccination. Researchers also caution that there is still important demographic inequality when it comes to the influenza vaccine.

“Less than half of US adults receive influenza vaccination each year, with Non-Hispanic Black, Hispanic, and American Indian/Alaskan Native individuals having had the lowest influenza vaccination coverage while also being disproportionately affected by SARS-CoV-2,” the researchers wrote.

The study was published in the journal Plos One.

COVID-19 survivors, even those who weren’t very sick, have a 50% greater risk of death

Credit: Pixabay.

Tens of millions of Americans have been infected with the virus thus far. But although the vast majority have recovered, long-term complications related to COVID-19 may continue to put their lives at risk. A new study that examined over 87,000 patients found that COVID-19 survivors had an almost 60% increased risk of death over the following six months compared with the general population.

“Our study demonstrates that up to six months after diagnosis, the risk of death following even a mild case of COVID-19 is not trivial and increases with disease severity,” said senior author Ziyad Al-Aly, MD, an assistant professor at the Washington University School of Medicine. “It is not an exaggeration to say that long COVID-19 — the long-term health consequences of COVID-19 — is America’s next big health crisis. Given that more than 30 million Americans have been infected with this virus, and given that the burden of long COVID-19 is substantial, the lingering effects of this disease will reverberate for many years and even decades. Physicians must be vigilant in evaluating people who have had COVID-19. These patients will need integrated, multidisciplinary care.”

Al-Aly and colleagues combed through a massive dataset from Veterans Health Administration (VHA) to comprehensively catalog all diseases that may be attributable to COVID-19. The dataset included 73,435 VHA patients with confirmed COVID-19 but who were not hospitalized and, for comparison, almost 5 million VHA patients who did not have a COVID-19 diagnosis and were not hospitalized during this time frame. Most of the veterans included in the study were men, but 12% were women so the results may still be relevant to both sexes.

In order to paint a more complete picture of the potential long-term effects of more severe COVID-19, the researchers also conducted a separate analysis involving 13,654 patients hospitalized with COVID-19 compared with 13i997 patients hospitalized with seasonal flu. Both analyses included six months of follow-up data.

According to the results, at the sixth-month mark, excess deaths among all COVID-19 survivors numbered 8 people per 1,000 patients. Among COVID-19 patients who were ill enough to be hospitalized and survived the first 30 days of illness, there 29 excess deaths per 1,000 patients.

“These later deaths due to long-term complications of the infection are not necessarily recorded as deaths due to COVID-19,” Al-Aly said. “As far as the total pandemic death toll, these numbers suggest that the deaths we’re counting due to the immediate viral infection are only the tip of the iceberg.”

Compared to the risk of death for flu survivors, the risk of death was 50% greater among COVID-19 survivors.

“Compared with flu, COVID-19 showed remarkably higher burden of disease, both in the magnitude of risk and the breadth of organ system involvement,” Al-Aly said. “Long COVID-19 is more than a typical postviral syndrome. The size of the risk of disease and death and the extent of organ system involvement is far higher than what we see with other respiratory viruses, such as influenza.”

Although COVID-19 is technically a respiratory illness, the virus can actually affect virtually every organ in the body. The researchers identified a number of persisting health issues associated with COVID-19. These include:

  • Respiratory system: persistent cough, shortness of breath, and low oxygen levels in the blood.
  • Nervous system: stroke, headaches, memory problems, and problems with senses of taste and smell.
  • Mental health: anxiety, depression, sleep problems, and substance abuse.
  • Metabolism: new onset of diabetes, obesity, and high cholesterol.
  • Cardiovascular system: acute coronary disease, heart failure, heart palpitations, and irregular heart rhythms.
  • Gastrointestinal system: constipation, diarrhea, and acid reflux.
  • Kidney: acute kidney injury and chronic kidney disease that can, in severe cases, require dialysis.
  • Coagulation regulation: blood clots in the legs and lungs.
  • Skin: rash and hair loss.
  • Musculoskeletal system: joint pain and muscle weakness.

Not all COVID-19 survivors will suffer from all of these health issues following their recovery. However, those who do have post-recovery health problems tend to develop a cluster of several issues.

“Some of these problems may improve with time — for example, shortness of breath and cough may get better — and some problems may get worse,” Al-Aly added. “We will continue following these patients to help us understand the ongoing impacts of the virus beyond the first six months after infection. We’re only a little over a year into this pandemic, so there may be consequences of long COVID-19 that are not yet visible.”

The findings appeared in the journal Nature.

Scientists are ‘encouraged’ by advanced universal flu vaccine

Credit: pixabay.

As 2020 draws near to a close, it’s quite clear that the world was not ready for a pandemic — but hopefully, we will avert those that may follow. Influenza viruses have been responsible for many pandemics in the past, including the devastating 1918 Spanish flu that killed 50 million people worldwide. But a universal flu vaccine developed by researchers at Mount Sinai Hospital could stop a future influenza outbreak dead in its tracks before it gets the chance to develop into a pandemic.

There are quite a few strains of influenza circulating among people that cause seasonal flu, which is responsible for about 650,000 deaths every year globally. In order to prevent infection, people can get vaccinated but the problem is that there are not only different flu viruses circulating, but viruses can also mutate. If antibodies from a previous infection or vaccine meet a virus whose surface structure they don’t recognize, then those receptors don’t match and they cannot block it.

This is why we have to take a flu vaccine every year — and they’re not perfect. These vaccines contain three or four strains of the influenza virus, which public health experts predict will be circulating in the subsequent season. The problem is that sometimes these predictions don’t match the reality in the field, with different strains actually circulating among the population.

For years, scientists have been working on a universal vaccine that would both offer protection against multiple known strains of influenza and prime the body against new outbreaks. Of course, that’s easier said than done, but a vaccine developed at Mount Sinai Hospital in New York City may be the most promising one so far.

The chimeric hemagglutinin (HA)-based vaccine targets different parts of the hemagglutinin protein, the major surface glycoprotein of the influenza virus that binds to host cell receptors.

“An influenza virus vaccine that results in broad immunity would likely protect against any emerging influenza virus subtype or strain and would significantly enhance our pandemic preparedness, avoiding future problems with influenza pandemics as we see them now with COVID-19” says Florian Krammer, Professor of microbiology at the Icahn School of Medicine at Mount Sinai, and corresponding author of the study.

“Our chimeric hemagglutinin vaccine is a major advance over conventional vaccines which are often mismatched to the circulating strains of virus, impacting their effectiveness. In addition, revaccinating individuals annually is a huge and expensive undertaking.”

Conventional vaccines produce neutralizing antibodies by targeting a part of the hemagglutinin, known as the globular head domain. The problem is that mutations help the virus escape neutralization through a process known as “antigenic drift”, according to Peter Palese, professor of microbiology and chair of the Department of Microbiology at Icahn School of Medicine at Mount Sinai, and co-author of the study.

“This genetic change, or shift, in the virus results in immunity to only specific strains of the influenza virus, requiring frequent re-formulation and re-administration of seasonal vaccines. Our chimeric HA vaccine, by contrast, is directed at the proximal part of the HA protein — the stalk domain — which has been shown to broadly neutralize diverse influenza virus strains in both animal models and humans,” he added.

Such a vaccine not only offers broad protection but is also multifunctional, in the sense that the antibodies it induces can neutralize many kinds of influenza viruses.

For countries that lack an advanced medical infrastructure and the resources to vaccinate their population every year, a universal vaccine would be extremely appealing. Most importantly, as this pandemic has shown, we need robust tools at our disposal in order to nip potential devastating outbreaks in the bud.

Of course, safety is first. In a phase 1 clinical trial that involved 65 participants in the United States, the researchers found that the vaccine produced a strong immune response that was still viable 18 months after vaccination.

“This phase of our clinical work significantly advances our understanding of the immune response in terms of its longevity,” said Dr. Krammer, “and leaves us greatly encouraged about future progress for this potentially breakthrough vaccine.”

The findings appeared in the journal Nature Medicine.

Scientists are working on a biosensor that detects COVID-19 and the flu at the same time

This sensor is the size of a micro USB drive and is capable of testing for influenza and COVID-19 simultaneously. Credit: Dmitry Kireev, University of Texas at Austin.

We’ve said it before, and we’re saying it again now: COVID-19 is much more dangerous than the flu. However, the two viral infections share some symptoms, such as fever and cough. In anticipation of the upcoming flu season in autumn and winter, researchers at the University of Texas are now working on a sensor that can differentiate between the two types of viruses from a single sample.

Having the flu during the pandemic can be confusing and downright scary since some of the symptoms overlap. Do you quarantine yourself because you’re not sure what’s going on? Do you go straight to the hospital to get a test, where you might actually risk contracting a coronavirus infection?

Researchers at the University of Texas are working on a dual test that might dispel such concerns, potentially saving millions in tax dollars and many man-hours for medical personnel.

“With a second wave of the coronavirus likely to appear right as we get into flu season, there’s an urgent need for diagnostics that can differentiate between COVID-19 and influenza,” said Deji Akinwande, a professor in the Cockrell School of Engineering’s Department of Electrical and Computer Engineering.

Previously, Akinwande and colleagues created a graphene-based biosensor that accurately detects iron deficiency in children. Graphene, the atom-thick sheet of carbon arranged in a honeycomb-shaped lattice, is very sensitive to charged particles. When combined with anti-ferritin antibodies, the biosensor becomes reactive to that one biomolecule.

Graphene is so sensitive that it can even detect tiny biomolecules, such as viruses.

“It became clear that just by changing the antibody, we could pivot the platform to focus on the coronavirus,” Akinwande said.

The dual test would be infused with antibodies of both the coronavirus and influenza, with one side being sensitive to COVID-19, while the other side reacts only to the flu.

The sensor, which is no larger than a micro USB drive, would save precious resources and save time for medical personnel. It would also reduce the usage of nasal swabs, currently in short supply.

Although there have been no sanctioned experiments yet, the research team plans on initially using inactive samples of coronavirus and influenza for their first tests. These early results will determine how well the sensor can connect to the coronavirus’ spike protein, which it uses to bind to human cells and cause infection.

If the prototype is proven effective, mass production will be ramped up as soon as the researchers find a suitable partner. For now, the dual test is supported by a grant from the National Science Foundation.

The more we look at COVID-19, the less it looks like the flu

If you went back in time to a month ago, you’d probably find many people wondering whether COVID-19 is worse than the flu. There’s no excuse for believing that now.

It’s hard to imagine that New York’s current situation, where it feels like “every day is 9/11”, is better than what most scenarios depicted. It truly is the challenge of a generation, and while the flu is also a major health burden in itself, this is nothing like the flu.

Initially, the case fatality rate reported in Wuhan, China, was around 2%. That was already much higher than the fatality rate of influenza, which is around 0.01% – 0.1%. Now, if we look at official numbers, it would seem that the case fatality rate is closer to 10% — this is the case in places like Italy, the UK, or New York. In reality, many more infected people aren’t being tested, so the real number of infections is much higher than the official one, which, in turn, brings the overall fatality rate lower.

But no matter how we look at it, it’s very different from the flu.

In New York, COVID-19 has already claimed more lives than the last five years of influenza put together, and it’s only been a couple of weeks since the outbreak started in the state — and that’s with a major lockdown, with drastic quarantine measures, with doctors coming out of retirement, and with the most concentrated health effort in modern history. It’s hard to imagine how the chart above would have looked if we all continued business as usual.

The problem is that this idea that “it’s just a flu”, that it’s nothing major, significantly slowed down containment measures. Even as the virus was surging through New York City, dozens of articles and photos showed New Yorkers taking to the parks and paying little attention to social distancing.

Now, the city’s municipality is burying unclaimed bodies in Potter’s Field on Hart Island.

The good news is that the COVID-19 epidemic in New York may be nearing its peak. The bad news is that as bad as it is, this is probably just the first wave — and things need to be managed carefully after this wave to ensure that the second wave isn’t even more devastating.

Much of this could have been avoided by an earlier response, and if more people had taken the disease more seriously. Similarly, much of the damage COVID-19 might cause in the future can be alleviated if we take it seriously and take individual precautions.

For the last time, it’s not the damn flu.

New approach neutralizes influenza with modified bacteria predator membranes

A team of German researchers has developed a new way to deal with seasonal and avian influenza viruses. Their approach involves wrapping the pathogens in chemically-modified bacteriophage capsids, rendering them unable to infect human cells.

Electron micrograph of coliphages (a type of bacteriophage) attached to a bacterial cell. Image credits: Dr Graham Beards via Wikimedia.

The team hopes their work will help usher in new treatment options against such viruses. The method was tested in the lab with very encouraging results and is currently under investigation for possible applications against the coronavirus.

Viral straightjacket

“Pre-clinical trials show that we are able to render harmless both seasonal influenza viruses and avian flu viruses with our chemically modified phage shell,” explained Professor Dr. Christian Hackenberger, Head of the Department Chemical Biology at the Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Leibniz Humboldt Professor for Chemical Biology at HU Berlin. “It is a major success that offers entirely new perspectives for the development of innovative antiviral drugs.”

Current antiviral treatments only attack the influenza virus after it has infected our cells, the team reports, which is certainly useful — but preventing infection in the first place would be much more desirable and effective.

The trials — which used infected human lung tissue samples — showed that perfectly fitting a phage capsid onto these viruses can be used to neutralize their ability to infect lung cells. The capsid was specially developed by the team for this job, and works by binding itself to all the (hemagglutinin) proteins the virus can use to gain access through the membranes of human cells. During the infection process, these proteins bind to sugar molecules sprinkled through the membrane of lung tissue cells to allow entry. The core mechanism of this process, however, relies on the virus creating multiple bonds with a cell, rather than a single one.

Their quest to develop an inhibitor for these proteins started six years ago. The plan was to make such an inhibitor functionally resemble the membrane of a human lung cell. The team’s quest led them to the Q-beta phage, a harmless species of bacteriophage that lives in our intestines and usually preys on E.coli. The team removed and attached ligands (binders) to its casing — sugar molecules in this case — to act as bait binding sites for the virus’ proteins

“Our multivalent scaffold molecule is not infectious, and comprises 180 identical proteins that are spaced out exactly as the trivalent receptors of the hemagglutinin on the surface of the virus,” explained Dr. Daniel Lauster, a former Ph.D. student in the Group of Molecular Biophysics (HU) and now a postdoc at Freie Universität Berlin. “It therefore has the ideal starting conditions to deceive the influenza virus — or, to be more precise, to attach to it with a perfect spatial fit. In other words, we use a phage virus to disable the influenza virus!”

When samples of tissue infected with flu viruses were treated with the phage capsid, the influenza viruses were practically unable to reproduce. High-resolution cryo-electron microscopy and standard cryo-electron microscopy revealed that the modified capsids completely cover the viruses.

While definitely encouraging, the findings call for more preclinical studies to assess the method’s viability and safety for human use. We don’t yet know, for example, if the capsids themselves would elicit an immune response in mammals, and if such a response would enhance or impair their effect. And, of course, it has yet to be proven that the inhibitor is also effective in humans.

For now, the team is content to know that their approach has great potential and that it is “the first achievement of its kind in multivalency research,” according to Professor Hackenberger. The approach, he adds, is biodegradable, non-toxic, doesn’t cause an immune response in cell cultures, and is, at least in principle, applicable to other viruses and possibly even bacteria. The team is currently focusing on adapting it to the SARS-CoV-2 virus.

The paper “Phage capsid nanoparticles with defined ligand arrangement block influenza virus entry” has been published in the journal Nature Nanotechnology.

People are less likely to catch common cold if they’re already infected with influenza

Flu and the common cold are both respiratory illnesses, but they are caused by different viruses. It can be difficult to tell the difference between them based on symptoms alone because they have similar symptoms. In general, colds are usually milder than flu and are more likely to have a runny or stuffy nose while influenza (the flu) can have very serious associated complications.

A new study by scientists from the Medical Research Council-University of Glasgow Centre for Virus Research found that people were less likely to catch either influenza or a common cold-causing rhinovirus if they were already infected with the other virus. Understanding how these distinct viruses hinder each other could be useful to improve forecasting models that predict respiratory disease outbreaks and strategies for controlling disease spread.

It has been observed before that common cold infections appear to be less frequent in the influenza season and vice versa. The study, published in the journal Proceedings of the National Academy of Sciences, is the first study with enough samples to provide strong evidence for this interaction at both the population and individual level.

Samples from 44,230 cases of acute respiratory illness, in 36,157 patients, were tested for 11 types of respiratory viruses over nine years in NHS Greater Glasgow and Clyde. Using this data, the researchers found that 35% tested positive for a virus and, of those, 8% were co-infected with more than one type of virus. The study looked at how 11 viruses interacted and found relationships between some of the other virus pairs, but these were not consistent at both the individual host and population level, which the study did find for influenza A and rhinovirus.

The most striking interaction they found was between influenza A viruses and rhinoviruses, a type of virus that can cause the common cold. Computer modeling of the data found that the inhibitory interactions between influenza and rhinoviruses appeared to occur within individual people as well as at a population level. Patients with influenza A were approximately 70% less likely to also be infected with rhinovirus than were patients infected with the other virus types.

The first author of the paper, Dr Sema Nickbakhsh from MRC-University of Glasgow Centre for Virus Research at the University of Glasgow, said: “One really striking pattern in our data is the decline in cases of the respiratory virus rhinovirus, which is typically a mild common cold-causing virus, occurring during winter, around the time that flu activity increases. In the same way as lions and spotted hyenas compete for food resources in the Masai Mara, we believe respiratory viruses may be competing for resources in the respiratory tract. There are various possibilities we’re investigating, such as these viruses are competing for cells to infect in the body, or the immune response to one virus makes it harder for another unrelated virus to infect the same person.”

Viruses from the same species – for example, different strains of influenza – could be expected to compete or generate an overlapping immune response in the body, but the researchers say what makes these findings interesting is the interaction between completely different types of viruses.

Dr Pablo Murcia, who led the research, said: “Traditionally people have studied viruses in isolation – you study only flu or rhinovirus – but we’ve shown here that we need to also be studying these viruses together like it’s an ecosystem. My team are now doing experiments to try and understand how respiratory viruses, including influenza and rhinovirus, interact. If we understand how viruses interact and how certain viral infections may favor or inhibit each other, then maybe we can develop better ways to target viruses. Studying interactions between viruses could help to explain why different viruses circulate in different seasons or why they affect different age groups, and within the body why certain types of viruses infect different parts of the respiratory tract, like the nose or the lungs.”

An example of how these viruses could also affect each other’s spread at a population level is the scenario where a person infected with one virus is more likely to stay home and consequently not catch another virus. Limitations of the study include: 1) the correlations observed cannot show what is causing these interactions and 2) samples were only taken from people with symptoms of a respiratory infection, so it may not capture how the viruses behave in people who do not develop symptoms.

Diabetes rising worldwide: one in 11 adults affected

Diabetes is one of the world’s fastest growing chronic diseases with over 463 million adults (that’s 1 in 11 adults) around the world living with this chronic medical condition according to new data published in the 9th Edition of the International Diabetes Federation (IDF) Diabetes Atlas. The latest Atlas also reports that the global prevalence of diabetes has reached 9.3%, with more than half (50.1%) of adults undiagnosed. A further 1.1 million children and adolescents under the age of 20, live with type 1 diabetes.

A decade ago, in 2010, the global projection for diabetes in 2025 was 438 million. With over five years still to go, that prediction has already been surpassed by 25 million. IDF estimates that there will be 578 million adults with diabetes by 2030, and 700 million by 2045.

Diabetes itself is not a major problem unless the blood glucose is uncontrolled and either rises too high or drops too low. If diabetes is not managed correctly (meaning blood glucose is not properly regulated), sufferers are likely to become progressively sick and debilitated.

Over time, diabetes can damage the heart, blood vessels, kidneys, eyes and nerves. For diabetics, maintaining blood sugar levels in a normal range — not too high or too low — is a lifelong challenge. Half of the people with diabetes die of cardiovascular disease (primarily heart disease and stroke), and 10–20 percent of people with diabetes die of kidney failure. Diabetes is also a major cause of blindness and lower limb amputation.

IDF estimates that approximately 4.2 million adults will die as a result of diabetes and its complications in 2019. This is equivalent to one death every eight seconds.

Flu season is quickly approaching and patients with diabetes are particularly at high risk of serious flu-related complications that can result in hospitalization or even death. Diabetics are twice as likely to die from heart disease or stroke as people without diabetes and six times more likely to be hospitalized. 

Flu infection can cause changes in blood sugar and prevent people with diabetes from eating properly, which further affects blood glucose. Moreover, diabetes can make the immune system less able to fight infections. Diabetes patients with flu face very serious health risks such as ketoacidosis (a condition when the body cannot use sugar as a fuel source because there is no insulin or not enough insulin) and Hyperosmolar Hyperglycaemic State (HHS).

It is important for people with diabetes to follow the sick day guidelines if they become ill. Flu vaccination is especially important for people with diabetes because they are at high risk of developing serious flu complications. Flu vaccination has also been associated with reduced hospitalizations among people with diabetes (79%). Diabetics who get the flu should ask their doctors about prescription antiviral medications that can ease symptoms and shorten the duration of the illness. For best results, antivirals should be taken within 48 hours of the onset of flu symptoms.

Got a heart condition? High blood pressure? Beware of the flu

Influenza vaccination in patients with high blood pressure is associated with an 18% reduced risk of death during flu season, according to research presented today at European Society of Cardiology (ESC) Congress 2019 together with the World Congress of Cardiology.

“Given these results, it is my belief that all patients with high blood pressure should have an annual flu vaccination,” said Daniel Modin research associate at the University of Copenhagen, Denmark. “Vaccination is safe, cheap, readily available, and decreases influenza infection. On top of that, our study suggests that it could also protect against fatal heart attacks and strokes, and deaths from other causes.”

The study used Danish nationwide healthcare registers to identify 608,452 patients aged 18 to 100 years with hypertension during nine consecutive influenza seasons (2007 to 2016).

The researchers determined how many patients had received a flu vaccine prior to each season. They then followed patients over each season and tracked how many died.

They recorded death from all causes, death from any cardiovascular cause, and death from heart attack or stroke. Finally, they analyzed the association between receiving a vaccine prior to flu season and the risk of death during flu season. 

After adjusting for patient differences, in a given influenza season, vaccination was associated with an 18% relative reduction in the risk of dying from all causes, a 16% relative reduction in the risk of dying from any cardiovascular cause, and a 10% relative reduction in the risk of dying from heart attack or stroke.

He said: “Heart attacks and strokes are caused by the rupture of atherosclerotic plaques in the arteries leading to the heart or the brain. After a rupture, a blood clot forms and cuts off the blood supply. It is thought that the high levels of acute inflammation induced by influenza infection reduce the stability of plaques and make them more likely to rupture.”

In a study published earlier this year in Open Forum Infectious Diseases, investigators from Warren Alpert Medical School of Brown University, NYU School of Medicine, University of Groningen, and University of Toronto combed through published data on all-cause mortality rates among heart failure patients who received the influenza vaccine and found that flu vaccination was associated with a 31% decreased risk of all-cause mortality in those patients.

The effect was more prominent (51% lower risk) during influenza season. The authors drew from eight studies published since 2000, which included a total of 82,354 patients (average age of 65) with heart failure. They found that patients who had received seasonal flu vaccine had a reduced risk of all-cause mortality (hazard ratio [HR], 0.69; 95% confidence interval [CI], 0.51 to 0.87), especially during flu season (HR, 0.49; 95% CI, 0.30 to 0.69).

A study in Denmark published in Circulation in December 2018 looked at a cohort of 134,048 patients who were aged 18 years or older and diagnosed with heart failure in the period of January 1, 2003, to June 1, 2015.

The research team, composed of investigators from the University of Copenhagen and Harvard Medical School, found that frequent vaccination and vaccination earlier in the year (before the flu season in Denmark – September to October) were associated with larger reductions in the risk of death compared with intermittent and late vaccination.

Why do people with heart disease need the flu vaccine?

Influenza infection has been associated with an increased risk of heart attacks and worsening of chronic cardiovascular conditions.

Previous research has found that people with heart disease are at least six times more likely to have a heart attack after coming down with the flu. Because of the close relationship between heart failure and respiratory illness, with over half of heart failure complications thought to be triggered by respiratory infection, the role of influenza vaccination, which is widely available at low cost, has been described as a potential disease-modifying intervention.

In addition to the inflammatory effects of influenza infection, which have been linked to increases in atherogenesis, the production of pro-inflammatory cytokines during acute infection may directly depress myocardial contractility. Because of these recent evidences, the authors recommend seasonal flu vaccines for eligible heart failure patients.

Why are people more likely to get sick or die from flu during winter months?

In the temperate regions, between the subtropics and the polar circles, temperatures are not “extreme”, not burning hot nor freezing cold (temperate means moderate). In these parts of the world, seasonal influenza virus outbreaks happen during the winter months — peaking between November and March in the Northern Hemisphere (i.e. All of continental Europe, North America) and between May and September in the Southern Hemisphere (i.e. Australia, Zealandia, Brazil).

Scientists have hypothesized several reasons for this. Maybe because people are inside more in cold weather, one theory holds, so the virus spreads more easily. Or maybe it’s because people are not out in the sun making Vitamin D, and their immune systems are weak. Or perhaps people travel for holidays at certain times of years, helping spread the virus. So far, not one of these theories has proved a winner.

Recently, a group of researchers from Yale University, Veterans Affairs Connecticut Healthcare System, and Howard Hughes Medical Institute has pinpointed a key reason why people are more likely to get sick and even die from flu during winter months: low humidity.

The Yale research team, led by Akiko Iwasaki, the Waldemar Von Zedtwitz Professor of Immunobiology, explored the question using mice genetically modified to resist viral infection like humans do. The mice were all housed in chambers at the same temperature, but with either low or normal humidity. They were then exposed to the influenza A virus. The study was published in the Proceedings of the National Academy of Sciences (PNAS).

 

They found that low humidity hindered the immune response of the animals in three distinct ways: 1) it prevented cilia, which are hair-like structures in airways cells, from removing viral particles and mucus, 2) it also reduced the ability of airway cells to repair damage caused by the virus in the lungs, 3) in low humidity, interferons or signaling proteins released by virus-infected cells to alert neighboring cells to the viral threat do not function optimally. The study offers insight into why the flu is more prevalent when the air is dry.

“It’s well known that where humidity drops, a spike in flu incidence and mortality occurs. If our findings in mice hold up in humans, our study provides a possible mechanism underlying this seasonal nature of flu disease,” said Akiko Iwasaki.

While the researchers emphasized that humidity is not the only factor in flu outbreaks, it is an important one that should be considered during the winter season. Increasing water vapor in the air with humidifiers at home, school, work, and even hospital environments is a potential strategy to reduce flu symptoms and speed recovery, they said. In addition, it’s always a good idea to wash your hands often and get vaccinated with the flu vaccine.

More evidence showing that flu vaccination lowers risk of death in heart failure patients

Credit: Pixabay.

Patients diagnosed as having heart failure had an 18% lower risk of death if they subsequently received the seasonal influenza vaccine, according to a recent study published in Circulation, a journal of the American Heart Association (AHA).

The flu season is an annually recurring time period characterized by the prevalence of outbreaks influenza that occurs during the cold half of the year in each hemisphere. It usually starts late fall and runs through the spring, with flu cases peaking during the winter months.

Influenza can be very serious or even fatal for patients with heart failure because these patients are often older than 65, have other health complications, and infection exacerbates heart failure symptoms. Heart failure is expected to increase over the next decades as the world’s population ages and people live longer.  By 2050, the world’s population aged 60 years and older is expected to total 2 billion, up from 900 million in 2015.

Some people are at higher risk for serious flu complications, including young children, older people, pregnant women and people with certain chronic health conditions.

In this study, researchers analyzed data on 134,048 heart failure patients over a 12-year period from 2003 to 2015. After adjusting for income, co-morbidities, and other factors, the researchers found the following:

  • Flu vaccination was associated with an 18% reduced risk of premature death. Annual flu vaccination following a heart failure diagnosis was associated with a 19% reduction in both all-cause and cardiovascular death when compared with no vaccination.
  • Frequency of flu vaccination mattered — getting a flu vaccine less than once per year but more than not at all was associated with a 13% reduced risk of all-cause death and an 8% reduced risk of cardiovascular death.
  • Timing also mattered — there was a greater reduction in cardiovascular and all-cause death when vaccination occurred earlier in the flu season.

According to study lead author Daniel Modin of the University of Copenhagen, while their research only looked at patients with newly diagnosed heart failure, the protection from a flu vaccination likely benefits any patient with heart failure. The research team hopes the study can help in making physicians and cardiologists aware of how important flu vaccines are for their patients.

An earlier publication from 2013 analyzed six studies dating back to the 1940s concerning the heart health of over 6,700 men and women with an average age of 67. About a third had heart disease and the rest had risk factors such as high cholesterol, high blood pressure, and diabetes. They found that people who had received the flu vaccine were: 36% less likely to experience heart disease, stroke, heart failure or death from cardiac-related causes and 55% less likely to suffer a cardiac event if they had recently experienced a heart attack or stroke.

Several other studies have concluded that flu vaccination should be considered as an integral part of chronic heart diseases management and prevention. While the European Society of Cardiology, American College of Cardiology, American Heart Association, cardiology experts & many other health organizations recommend flu vaccines for patients with heart disease, rates of vaccination in these groups are low.

When it comes to influenza — Men Are from Mars, Women Are from Venus

Flu vaccine seems more effective in women; men recover faster from the flu.

Influenza (also known as the flu) is the smartest virus on the planet. Every year, seasonal influenza kills up to 650,000 people in the world, but when the flu season is over, people usually forget about the hundreds (or even thousands) who died and how bad the past flu season was. Until scientists create something more effective, the flu shot is still the best way to protect yourself and your family from flu and any associated illness. But no matter how often people are reminded to get the vaccine, and how often healthcare professionals tell patients compelling reasons to get vaccinated, flu shots are always a hard sell.

Scientists conduct studies each year to determine how well the influenza (flu) vaccine protects against flu illness. While vaccine effectiveness can vary, studies show that flu vaccination reduces the risk of flu illness by between 40% and 60% during seasons when most circulating flu viruses are well-matched to the flu vaccine. The vaccine’s effectiveness can also vary depending on the characteristics of the person being vaccinated (such as their age and health), and the similarity or “match” between the flu strains included in the vaccine and the flu viruses spreading in the community. However, gender appears to have a significant impact on the efficacy of the influenza vaccine as well according to a study entitled “Should sex be considered as an effect modifier in the evaluation of influenza vaccine effectiveness?” published in Open Forum Infectious Diseases.

It has long been known that gender can correlate with health with influenza. For example, women have increased exposure to influenza due to historical gender norms under which more women serve as primary caregivers than men. Nevertheless, men, although exposed less to the flu, tend to have higher rates of mortality and morbidity from the flu. Women are also more likely to be vaccinated than men, and they tend to seek health care more quickly when they are sick.

Colorized transmission electron micrograph showing H1N1 influenza virus particles. Surface proteins on the virus particles are shown in black. Credit: NIAID, Flickr.

Colorized transmission electron micrograph showing H1N1 influenza virus particles. Surface proteins on the virus particles are shown in black. Credit: NIAID, Flickr.

Investigators in this study wanted to ascertain the extent to which gender itself—not just cultural and behavioral norms around gender— could affect the effectiveness of the flu vaccine. To study the question, the investigators looked at a database of patients over seven flu seasons, from 2010-2011 to 2016-2017. Patients were included if they were at least 1-year-old and had seen a doctor within seven days of the onset of flu-like symptoms. Vaccination status was recorded based on patient self-reports and only those who had been given the flu shot at least two weeks before the diagnosis of flu were included in the study.

Results showed that women were less likely than men (43% versus 40%) to end up with a positive flu test and were more likely (29% versus 23%) to have received the flu shot. The overall vaccine effectiveness for women was considerably higher (49% versus only 38% for men). The difference in effectiveness varied by strain with the greatest dissimilarity in the A (H3N2) and B (Victoria) strains. Among patients not given the flu vaccine, there was no gender-based difference in influenza infection rates.

The authors wrote that “…these findings suggest that biological gender differences in response to the vaccine, rather than gender differences in health care seeking or vaccination status reporting, likely explains the observed differences in influenza VE between males and females.” In addition, the authors noted that previous research has suggested women have “stronger innate and adaptive immune responses, including more pronounced antibody response to influenza vaccine, in association with higher rates of local and systemic adverse events following immunization.”

Credit: Air Force District of Washington.

Credit: Air Force District of Washington.

Another possible biological cause for the difference in vaccine effectiveness is that testosterone can be immunosuppressive at high levels. The gender-based difference in vaccine effectiveness gap was most obvious among older adults (potentially because of age-related immune system changes or immunosenescence) and prepubescent children. According to corresponding author Danuta Skowronski MD, FRCPC, of the British Columbia Centre for Disease Control, if the findings are confirmed, one day physicians and vaccine developers might consider gender when developing newer influenza vaccines and flu prevention strategies.

This comes after the publication by scientists at Johns Hopkins Bloomberg School of Public Health in the journal Biology of Sex Differences showing that a protein called amphiregulin (AREG) could be the reason why men recover from influenza more quickly than women. AREG is an Epidermal Growth Factor (EGF)-like molecule that plays a critical role in wound and tissue healing following infection or injury.

Certainly, more evidence is needed before public health experts can say whether influenza prevention strategies should vary by gender or whether a gender-specific influenza prevention strategy is warranted. But for now we know that flu vaccine effectiveness seems to be higher in women but men seem to recover faster from the influenza infection.

Obesity May Also Increase Flu Spread, Not Just Flu Severity

Credit: Pixabay.

Obesity and overweight

Overweight and obesity are conditions where a person has accumulated an excessive amount of fat that may impair their health. A simple index used to classify overweight and obesity is the body mass index (BMI), which is defined as a person’s weight in kilograms divided by the square of his height in meters (kg/m2). To learn more about obesity, BMI and how it is measured, check this information page from the World Obesity Foundation and the video below.

Obesity and diseases

A high BMI is a major risk factor for non-communicable diseases such as cardiovascular diseases (mainly heart disease and stroke), diabetes, musculoskeletal disorders (especially osteoarthritis – a highly disabling degenerative disease of the joints), and some cancers (including endometrial, breast, ovarian, prostate, liver, gallbladder, kidney, and colon). The risk of these non-communicable diseases rises with increases in BMI.

Obesity and infections

Available data suggest that obese people are more likely than people of normal weight to develop infections of various types including postoperative infections (infections after surgical procedures) and other nosocomial infections (infections that are acquired in a hospital or other healthcare facility). Scientists already know that obesity increases a person’s risk of suffering from severe complications from influenza. Previous epidemiologic studies in Morbidity and Mortality Weekly Report and PLoS Medicine showed an association between obesity and severe complications and death from influenza, especially in the elderly. However, recently researchers who studied households in Managua, Nicaragua over three flu seasons found that it takes obese adults about 1.5 times longer to shed the virus than non-obese adults. This was published in the Journal of Infectious Diseases (JID).

Obesity and flu transmission

Dr. Aubree Gordon from University of Michigan School of Public Health, a senior study co-author, said in a press release from the Infectious Diseases Society of America (IDSA) that the findings are the first real evidence that obesity might affect more than just disease severity; “it might directly impact transmission as well.”

Flu vs cold

Credit: Pixabay / Sambeet.

The researchers monitored two groups including 1,783 people from 320 households during three flu seasons from 2015 to 2017. Among the group, 87 were infected with influenza A while 58 were sickened by influenza B. It took obese adults with two or more symptoms 42% longer to shed the influenza virus compared to adults who were not obese. Moreover, obese adults who had no symptoms or had milder infections shed the virus for 104% longer. However, obesity did not increase viral shedding in children ages 5 to 17 or for adults who had influenza B illness.

The researchers cannot say for sure how obesity could extend viral shedding in those with flu; however, it is a known fact that obesity alters the immune system and can lead to chronic inflammation, which also increases with age. The researchers also note that obesity can make breathing more difficult and increase the need for oxygen. They also suggest that chronic inflammation triggered by obesity could be responsible for increased shedding of influenza A. Reducing obesity rates can have the benefit of limiting the spread of viral diseases, the authors said. Further research is needed to determine whether the flu virus shed over longer periods by obese patients is infectious and if it is able to infect others.

A commentary on the study was included in the same JID issue by Dr. Stacey Schultz-Cherry of St. Jude Children’s Research Hospital who was not involved in the study. Dr. Schultz-Cherry noted that more studies are needed to determine whether the longer shedding duration in obese people is correlated with increased viral load and shedding of infectious viral particles.

She added that this report of longer shedding of virus and a recent study of exhaled breath in college students — which found a link between obesity and the amount of flu virus shedding — suggest that obesity may play an important role in flu transmission. This link has important public health implications, including a threat of more flu transmission that goes along with increasing obesity prevalence. Dr. Schultz-Cherry noted that strategies to prevent flu could be a challenge because of poor vaccine response in overweight and obese populations.

A lung-healing protein could be the reason why men recover from flu faster than women

In the United States, during the 1957 H2N2 pandemic, the number of deaths was higher among females than males. During the first and second wave of the 2009 H1N1 pandemic, a significant portion of patients hospitalized with severe 2009 H1N1 disease was comprised of young adult women. Data from the 2009 H1N1 pandemic, as well as from 2005, which was a bad year for seasonal influenza in Japan, reveal significant differences in morbidity rates between males and females. In 2010, the WHO published a report concluding that the outcome of pandemic influenza, as well as avian (bird flu) H5N1, is generally worse for young adult females.

pregnant woman

Credit: Public Domain

Pregnancy is an obvious female-specific risk factor associated with worse outcomes from seasonal and pandemic influenza infection, and likely contributes to the overall higher mortality in women compared to men. However, it does not appear to explain all of the differences between the sexes. Some researchers have postulated that the slower recovery by women from flu was linked to their greater levels of lung inflammation during flu infections. What else could be the reason?

According to a new study of mice and human cells, increased amounts of a lung-healing protein called amphiregulin (AREG) could be the reason why men recover from influenza more quickly than women. AREG, an Epidermal Growth Factor (EGF)-like molecule, has been shown to play a critical role in wound and tissue healing following infection or injury.

Vermillion, MS et al. Biology of Sex Differences 2018. 9:24

Scientists at Johns Hopkins Bloomberg School of Public Health, whose findings were published in the journal Biology of Sex Differences, infected live mice and human cells derived from male humans with a non-lethal dose of H1N1 — an Influenza A strain that caused over 18,500 laboratory-confirmed deaths worldwide in 2009 and 2010. Male and female mice had the same virus levels and cleared the virus in about the same amount of time.

Nevertheless, female mice had greater loss of body mass and more lung inflammation during the early phase of infection and were slower to return to normal lung function. Male mice genetically engineered to lack AREG had the same flu results as females. In a study of flu infections of mice and human lung epithelial cells in vitro, the investigators found significant increases in the production of AREG only when the cells were from males.

“The novel finding here is that females also have slower tissue-repair during recovery, due to relatively low production of amphiregulin,” study author Dr. Sabra Klein, an associate professor at Hopkins, said in a press release.

Scientists found that AREG, which has been known to promote the growth of epithelial cells in the skin, lung, and other surfaces in the body during wound healing, was the key factor, including during recovery from lung infections. Male mice produced significantly more AREG than females during the recovery phase of their infections.

It is not clear which factors drive the increased rise in AREG production in males during flu infection. Earlier in 2016, Professor Klein and colleagues showed that the sex hormone progesterone stimulates AREG production in female mice. They theorized that males evolved with greater wound-healing ability because they participated in more battles for territories, mates, and resources. The researchers initially thought the production of AREG increased in males during influenza infection because of testosterone. However, they found that the sex hormone, independently of AREG, does help protect male mice, which fared worse in flu infections without it.

Professor Klein’s group is now investigating the mechanisms of testosterone’s protective effect, as well as the factors that control AREG production during flu infection – a better understanding of these mechanisms could lead to new flu treatments that boost AREG production, particularly in women.

Credit: Pixabay.

Dog flu might cause the next influeza pandemic

Just like the H1N1 virus jumped from birds to humans in 2009, so might a new strain of influenza do the same in the future, only this time it could originate from our best friends — dogs.

Credit: Pixabay.

Credit: Pixabay.

After bird and swine flu caused a stir in recent years, a new threat may be on the horizon. Scientists have found that dogs carry an increased diversity of flu strains, as well as evidence that the flu can spread from pigs to dogs, a pattern that’s eerily similar to the build-up for the H1N1 pandemic.

“The majority of pandemics have been associated with pigs as an intermediate host between avian viruses and human hosts,” says one of the researchers, Adolfo García-Sastre, from the Icahn School of Medicine at Mt Sinai in New York.

“In this study, we identified influenza viruses jumping from pigs into dogs.”

Fifteen years ago, researchers documented an influenza virus that had infected a horse before jumping into a canine, signifying the first circulating canine influenza virus. Five years ago, another study reported the first case of influenza passing from a bird to a dog. Now, new research shows that influenza can also circulate from pigs to dogs.

The team of researchers — who are based at the Center for Research on Influenza Pathogenesis Icahn School of Medicine at Mount Sinai in New York City, NY — sequenced the genomes of 16 influenza viruses that were sampled from 800 dogs in Southern China between 2013 and 2015. The canines attended veterinary clinics due to respiratory problems and around 15 percent of them had influenza.

The analysis revealed that viruses that come from swine, and that are avian in origin, are now jumping into dogs.

“We now have H1N1, H3N2, and H3N8 in dogs. They are starting to interact with each other. This is very reminiscent of what happened in swine 10 years before the H1N1 pandemic,” the authors reported.

In 2009, avian flu jumped to pigs, where it mixed with existing strains, ultimately leading to a hybrid virus that could infect humans. It was a totally new strain to which humans had not had the chance to develop any immunity against.

The present findings, however, don’t imply that flu strains developing in dogs are going to be harmful to humans. It’s just that they might. As the viruses mix and become more diverse, the chances increase that they could become capable of infecting humans. That being said, there is no reason to panic yet — especially considering that the dogs included in the study were sampled from a single region of China. If in the future scientists find any reason for concern, the virus can be kept at bay through vaccination programs.

The findings have been published in the journal mBio.

A fiber-rich diet can protect against the flu

Researchers have found an unexpected ally for protecting the body against the flu: dietary fiber.

Want to avoid the flu? Eat more fiber, a new study suggests.

More and more research is showing just how important our diet is for preventing a number of diseases and health conditions. It’s not just about straightforward problems, like diabetes or cardiovascular diseases — sometimes the prevention effect can be rather surprising. In this case, it seems that dietary fiber can blunt excessive and harmful immune responses in the lungs, while at the same time boosting antiviral immunity by activating T cells. This whole process is mediated by changes in the composition of gut bacteria.

“The beneficial effects of dietary fiber and SCFAs on a variety of chronic inflammatory diseases, including asthma and allergies, have received substantial attention in recent years and have supported momentum toward their use in clinical studies,” says senior study author Benjamin Marsland of Monash University. “But we were concerned that these treatments might lead to a general dampening of immune responses and could increase susceptibility to infections.”

Influenza, commonly known as “the flu”, affects millions of people every year, being one of the most common viral infections in the world. Aside from being extremely unpleasant, influenza can also be dangerous — and in some cases, fatal. Finding a way to boost immunity through diet alone would be a valuable tool for public health.

Dietary fiber is essentially the indigestible portion of food derived from plants. Although we don’t digest it directly, we can still draw a number of very important benefits from them. Dietary fiber helps keep our digestive system healthy, fighting obesity and severe diseases such as bowel cancer. It generally does this by keeping your gut bacteria healthy, but in the case of influenza, it’s a bit strange: the fiber seems to selectively turn on some parts of the immune system while switching others off — both to positive effect.

“We typically find that a certain treatment turns our immune system either on or off,” Marsland says. “What surprised us was that dietary fiber was selectively turning off part of our immune system, while turning on another, completely unrelated part of our immune system.”

This study also suggests that the so-called Western diet (high in sugars and fats, low in fiber) increases susceptibility to inflammatory diseases while decreasing protection against infections, something which has already been confirmed.

However, this study has only been carried out on mice. There’s a good chance the results will carry over to humans (something which researchers will test in the near future), but it remains to be seen if this is the case. At any rate, adding more fiber to your diet is always recommended, and will almost certainly provide significant health benefits.

Journal Reference: Immunity, Trompette and Gollwitzer et al.: “Dietary Fiber Confers Protection against Flu by Shaping Ly6c- Patrolling Monocyte Hematopoiesis and CD8+ T Cell Metabolism” http://www.cell.com/immunity/fulltext/S1074-7613(18)30191-2

Scientists identify new Flu H1N2 from a mix of two other influenza viruses

Mutation is an important source of RNA virus diversity that happens because the nature of RNA synthesis is prone to error. This is one of the reasons why the flu vaccine composition is changed each year. For influenza viruses, with segmented genomes, another mechanism for generating diversity is through reassortment. If a cell is infected with two different influenza viruses, the RNAs of both viruses are copied in the nucleus. When new virus particles are assembled, each of the RNA segments may originate from either infecting virus. The resulting “new” flu viruses inherit RNAs from both parents and are called reassortants.

From Eric J. Ma (Department of Biological Engineering, MIT)

 

Tests in the Netherlands identified a reassortant H1N2 seasonal flu infection in a toddler who was seen at a clinic that was part of the sentinel surveillance network. The flu virus is described as reassortant because it is a mix of A(H3N2) and A(H1N1) – the flu virus has eight gene segments and this particular virus consists of 6 gene segments from the A(H3N2) virus (PB1, PB2, PA, NP, NA, M) and 2 gene segments from the A(H1N1)pdm09 virus (HA, NS).

Reassortant Flu H1N2 (Dr Melvin Sanicas)

 

The 19-month-old boy’s symptoms began in early March, and he was taken to a clinic three days later. He had not traveled, been vaccinated, taken antivirals and had no underlying health conditions. Real-time reverse transcriptase polymerase chain reaction (RT-PCR) and nanopore sequencing confirmed the H1N2 reassortant in mid-March. After the boy’s initial clinic visit, he was seen again for an ear infection and he recovered fully after antibiotic treatment.

According to the investigators, increased virulence (severity of the resulting disease symptoms) is not expected and there were no mutations to suggest resistance to antivirals had been identified. Reassortant seasonal viruses have been reported previously. The spread of these viruses was limited, but in one case, circulation continued for three seasons with a reassortant of a former seasonal A(H1N1) and A(H3N2) influenza virus. A reassortant of A(H1N1)pdm09 and A(H3N2) has only been found in India. In the Netherlands, the 2017-2018 influenza season is dominated by influenza B/Yamagata lineage viruses, but the Dutch National Influenza Center characterized around 600 influenza type A viruses, only one of which (the case reported here) was of the H1N2 subtype. There is thus no evidence of an extensive spread of the A(H1N2) virus, but laboratories should remain on alert. The rise of a reassortant that contains the 2009 H1N1 virus would be a serious concern, because the 2009 H1N1 virus is well-adapted to humans and presents an ideal background for the spread of novel strains.

New studies describe a link between influenza and parotitis

Parotitis is the inflammation and swelling of the salivary glands. 

Parotitis is the inflammation and swelling of one or both salivary glands. The only known cause of epidemic parotitis among humans is mumps, a vaccine-preventable disease caused by the mumps virus, a member of the Rubulavirus genus of the Paramyxoviridae family. Before the approval of the mumps vaccine in the late 1960s, mumps was one of the most frequently reported diseases during childhood. Since 1990, the Advisory Committee on Immunization Practices (ACIP) has recommended children routinely receive two doses of measles–mumps–rubella vaccine (MMR) and this had a significant impact on reducing the occurrence of mumps.

According to two new articles published in Clinical Infectious Diseases, parotitis may be a complication of infection with the influenza virus. Both studies reviewed recent non-mumps related cases of parotitis following influenza and other viral infections, showing that after mumps had been ruled out, doctors and healthcare professionals should consider influenza when examining a patient who presents with parotitis. Furthermore, the investigators found that influenza A(H3N2), the flu strain behind the northern hemisphere 2017-2018 severe flu season, may be more likely to cause parotitis.

The first study by researchers from the US Centers for Disease Control and Prevention (CDC) investigated the etiology and clinical features of parotitis not caused by mumps during the 2014-2015 US influenza season in 320 American cases. The cases occurred in 27 states, mostly in men (65%). Almost two-thirds of patients (64%) were under 20 years of age. The subjects answered a questionnaire about their illness, and the CDC tested patient samples for several viruses. Viruses were detected in 210 buccal swab specimens (71%) of 294 non-mumps parotitis (NMP) patients with adequate samples for testing. These included 156 influenza A(H3N2), 42 human herpesvirus 6B (HHV6B), 32 Epstein-Barr virus (EBV), 8 human parainfluenza virus type 2 (HPIV2), 2 human parainfluenza virus type 3 (HPIV3), 3 adenovirus, 4 herpes simplex virus type 1 (HSV-1), and 1 herpes simplex virus type 2 (HSV-2). Influenza A(H3N2), HHV6B and EBV were the most frequently co-detected viruses. Because buccal swab specimens are not optimal for detecting influenza RNA, it is possible that the results underestimate the presence of influenza.

The second study by the same group of CDC researchers focused on interviews with 50 patients who had parotitis and were lab-confirmed to have an influenza infection between February to April of 2015. The results were compared with responses from 124 patients with lab-confirmed influenza infections that did not have parotitis. Patients described painful facial swelling, consistent with acute parotitis, which developed shortly after the onset of systemic or respiratory symptoms. Facial swelling lasted for about four days before subsiding. Seven cases were severe enough for the patients to be hospitalized during their illness, this includes two patients who were admitted to the intensive care unit (ICU). Their findings suggest that it may be prudent to include influenza in the differential diagnoses among patients who present with acute parotitis, particularly during flu seasons where influenza A(H3N2) is the dominant strain circulating.

So does the influenza virus cause parotitis?

Other reports of influenza A (H3N2) infection among patients with parotitis during the same flu season in Canada, England, and Scotland show that there is consistency.

In the accompanying commentary by Andrew Pavia, MD, of the Division of Pediatric Infectious Diseases at the University of Utah in Salt Lake City, he noted that the presence of the influenza virus detected in over half of patients with non-mumps parotitis adds strength to the association between flu and parotitis but does not prove it. He wrote, “In the absence of experimental data or the demonstration that influenza virus replicates in salivary glands, it will be hard to prove to a high degree of scientific certainty that influenza causes parotitis.” However, these two studies “strongly suggest that parotitis can be added to the long list of syndromes caused by influenza.”