Tag Archives: common cold

How long are you contagious with a cold or flu?

Credit: Pixabay.

With the COVID-19 pandemic still sweeping the world, it’s easy to forget about the annoying, yet far more benign viral infections that plagued us thus far.

The flu and the common cold are some of the most common respiratory infections. Both are caused by highly infectious viruses, although from different families of viruses.

The common cold is caused by over 200 different viruses. About 30-35% of all adult colds are caused by rhinoviruses, but some cases are also caused by a handful of coronaviruses, the older cousins of the virus that causes COVID-19. This huge diversity of viruses is one of the reasons why we don’t yet have a universal vaccine for the common cold.

Meanwhile, the flu is caused by only a couple of influenza viruses, enabling researchers to develop new vaccines every year to neutralize new mutations and keep seasonal outbreaks at bay.

How long are you contagious with the flu?

The typical incubation period for influenza is one to four days, meaning it takes about that much time for symptoms to show after the initial infection. However, people can pass on the illness to others a day before the onset of symptoms and up to seven days after symptoms first show. The most infectious period is 3 to 4 days after you start feeling sick.

Children and adults with poor immune systems may be infectious for a few days longer.

Like most respiratory viruses, influenza is spread through direct contact, from one person to another. This can happen when an infected person sneezes or coughs into the air and then a susceptible host comes in contact with these viral-loaded droplets of moisture.

In order to protect co-workers and school colleagues, Dr. William C. Wilson, who is the chief medical officer of the University of California Irvine Health, recommends you make sure you check all item on this list to be on the safe side:

  • No fever for 24 hours — without fever-reducing medications
  • No vomiting or diarrhea for at least 24 hours
  • Coughing or sneezing should be reduced and intermittent

How long are you contagious with the common cold?

People sick with the common cold will be contagious for much longer than is the case for the flu. While people sick with the flu will generally stop being contagious after a week, those sick with the common cold may be contagious for up to three weeks.

It depends a lot on the kind of virus involved. If the common cold symptoms are caused by a rotavirus, you can spread it to others even before you develop symptoms — and up to two weeks after you’ve recovered.

Generally speaking, you’ll be contagious 1-2 days before the onset of symptoms and for up to 2 weeks. You’re more likely to infect others during the first few days, when symptoms are at their worst.

After common cold symptoms fade away, you should still wait 24-36 hours before returning to your normal work or work schedule.

How do I know if I have the cold or the flu?

Many symptoms for both types of viral infections overlap, such as cough, runny nose, and feeling tired, which can make it challenging to tell the difference between the two.

Colds come on gradually over a few days and are often milder than the flu. They usually get better in 7 to 10 days, although symptoms can last for up to 2 weeks.

Flu symptoms come on quickly — often within 1 to 3 days — and can be severe. Basically, if you wake up one morning suddenly feeling like you’ve been hit by a truck, it’s likely the flu. Symptoms usually last 1 to 2 weeks.

Influenza is responsible for head and body aches, whereas cold aches are much milder.

With a cold, you may or may not feel tired. With the flu, however, tiredness and weakness are common.

Some people get a slight fever when struck by a cold, but most don’t. In contrast, any fever above 38 degrees Celsius (101 to 104 degrees Fahrenheit) is a sign of the flu, with children’s fevers tending to be higher.

Tips for returning to work after being ill with the flu or common cold

If you’ve gained at least 90% of your energy back and overall symptoms are gone or decreased significantly, it may be safe to return to work or engage in social activities. When you do return, remember:

  • Wash your hands frequently and sanitize any surfaces such as computer keyboards and telephone handsets and receivers.
  • Protect your coworkers by avoiding those with weakened immune systems.
  • If you are still coughing or sneezing, wear a medical mask to prevent the spread of virus-filled droplets.
  • Sneeze or cough into a tissue or into the bend of your elbow — not your hand — to keep droplets from spreading.
  • Ease back into your work pace to allow your body to recover fully and to prevent yourself from relapsing back into illness.

Common cold may prime the immune system against coronavirus for COVID-19

Credit: Wikimedia Commons.

SARS-CoV-2, the virus that causes COVID-19, took the world by storm when it suddenly surfaced in Wuhan, China, at the end of 2019. SARS-CoV-2 belongs to the family of coronaviruses, which owe their name to a crown-like protein that these viruses use to attach to specific cell receptors in order to infect them.

Obviously, SARS-CoV-2 isn’t the first coronavirus known to science. In fact, some of them are known to cause the common cold — and getting sick with the cold might offer some protection against the new coronavirus, scientists report in a new study published this week.

Alessandro Sette, a Professor at the La Jolla Institute for Immunology, has dedicated more than 35 years of his career to understanding the immune response and measuring immune activity. Sette and colleagues were initially stunned to see an immune response to SARS-CoV-2 in blood samples collected before the COVID-19 pandemic. Either the novel coronavirus landed in the San Francisco area much earlier than believed, which is almost impossible, or something different was at play.

The only viable explanation the researchers could think of was that some people must have been exposed to some older cousins of SARS-CoV-2, which primed their immune system against it, despite having never been sick with COVID-19.

There are four coronaviruses that are known to cause the common cold. These are 229E, NL63, OC43, and HKU1, which usually cause mild to moderate upper-respiratory tract illnesses.

To put their theory to the test, Sette and colleagues sampled blood from San Diego residents that were collected well before the pandemic began. After the researchers matched the viral regions, they noticed that immune cells revved up, suggesting that some people’s immune systems could respond both to the previous coronaviruses and to the novel virus.

These findings have been confirmed by previous studies performed on patients from the United States, United Kingdom, Netherlands, Germany, and Singapore. According to their results, these studies suggest that between a fifth and half of those who’ve never been exposed to SARS-CoV-2 have already had some immune response to it.

This seems to be true for other coronaviruses, such as SARS-CoV-1, which caused a small epidemic in 2003. Francois Balloux, the director of the Genetics Institute at the University College of London, highlighted a recent study published in pre-print, which found all 24 participants from Singapore infected with SARS-CoV-1 in 2003 also have immune cells against SARS-CoV-2. That’s despite more than half of them never having been exposed to the novel coronavirus.

In light of these findings, it may be possible that a proportion of the population may have pre-existing immunity to SARS-CoV-2, perhaps due to prior exposure to coronaviruses that cause the common cold.

However, it’s important to note that no study thus far has proven that exposure to previous coronaviruses offers protection against COVID-19. But that may very well be the case. It would also explain why the impact of the virus seems so unpredictable across the same demographics — some recover with only mild symptoms while others are hit hard as if by a train.

Also, some readers should bear in mind that there are only four coronaviruses responsible for the common cold — a respiratory illness that is caused by over 200 different viruses. The large number of viruses that cause the common cold is one of the reasons why there is no vaccine for it. Meanwhile, there are only a handful of strains of influenza that regularly infect humans, a manageable number that has enabled scientists to produce vaccines for the flu.

So just because you were sick with the cold, that doesn’t mean you actually picked up coronaviruses to prime the immune system against COVID-19 — if such protection genuinely exists in the first place.

Much of this confusion may be dispelled after ongoing COVID-19 vaccine trials measure the T cells and antibodies required to actually prevent illness.

The new study’s findings appeared in the journal Science.

That mysterious China virus? It’s reached Washington

There are still many things we don’t yet know about the novel coronavirus, but one thing’s for sure: it’s not going away anytime soon.

It all started in China — in a Wuhan seafood market. Several people came down with what appeared to be a pneumonia-like virus.

The virus was genomically sequenced, and researchers confirmed that it is in the same family as SARS, MERS, and the common cold. But it’s pretty nasty, and there’s no confirmed treatment for it at the moment.

The virus was spreading from animal to animal, but it recently seems to also be capable of jumping from animal to human — and in some cases, even from human to human. This makes it particularly dangerous, and China has been actively trying to contain its spread.

But it’s not working very well.

As the World Health Organization is planning to meet in Geneva to decide whether the outbreak is a public health emergency of international concern, the CDC has reported that the disease has reached the US.

“The Centers for Disease Control and Prevention (CDC) today confirmed the first case of 2019 Novel Coronavirus (2019-nCoV) in the United States in the state of Washington. The patient recently returned from Wuhan, China, where an outbreak of pneumonia caused by this novel coronavirus has been ongoing since December 2019,” the statement reads. The US is already carrying screening at several airports, including New York and Atlanta.

It’s not clear how easily the virus can spread for human to human; but until recently, medics didn’t think this was possible at all. There are concerns that this may echo a 2003 episode, where a severe acute respiratory syndrome (also caused by a coronavirus from China) spread to more than 30 countries. Right now, determining how easily the virus spreads from person to person is vital, but that’s not clear yet. Determining the best course of treatment (or developing a new treatment) is also crucial.

So far, there have been over 300 confirmed cases, and the virus has already claimed six lives. The virus has already gone international, reaching Taiwan, Thailand, Japan, South Korea, and the Philippines. North Korea has reportedly shut down its borders for tourists until the situation clarifies.

In China, the virus has already reached Beijing, Shanghai, and Shenzen — three of China’s most populous cities. As hundreds of millions of Chinese people are expected to travel for the upcoming Lunar New Year holiday, the viral dispersion may be further widened.

Signs of infection include respiratory symptoms, fever, cough, shortness of breath and breathing difficulties, largely similar to pneumonia.

If you have been in contact with anyone from these infected areas and have similar symptoms, do report to the doctor. The World Health Organization has advised people to avoid “unprotected” contact with live animals and thoroughly cook meat and eggs.

This article was edited as the virus has reached Washington state, not Washington DC (as was initially stated).

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.

Common cold.

New research shows why some people get the common cold more easily

New research shows how different human cells respond to rhinovirus, the vector of the common cold. The results could help explain why some people are more susceptible to the disease than others.

Common cold.

Image credits Myriam / Pixabay.

Common colds, asthma attacks, and a host of other diseases associated with the respiratory tract share a common cause — rhinoviruses. However, not all people are made the same: some are more resistant to the pathogen, while others collapse into bed at the merest whiff of it.

In a bid to understand why, one team from the Yale University studied how key human cells respond to the pathogen.

Where’s the chicken soup?

To get to the bottom of things, the team worked with epithelial cells harvested from the nasal passages or lungs of healthy human donors. The team exposed both types of epithelial cells — kept in cultures under the same environmental conditions — to the virus.

Epithelial cells are a specialized type of cell that creates membranes and linings throughout the body. They’re usually the first bits to come into contact with pathogens, and, as such, possess traits that help them fight off bacteria and viruses. Rhinoviruses also have to contend with these cells when trying to infiltrate the body. Upon exposure to the bugs, epithelial cells lining our airways react to the threat, usually clearing it out of our systems before it gets a foothold and triggers symptoms. In some cases, however, this mechanism doesn’t seem to work: exposed to rhinoviruses, they fall mildly, or even seriously, ill.

The team reports that under business-as-usual scenarios, nasal cells have the more robust antiviral reaction among the two samples of cells. Further lab tests involved activation of the RIG-I pathway — a pattern-recognition network that the body uses to identify pathogens — in both types of sample cells so the team could see how each operated under emergency scenarios.

Upon activation of the RIG-I network, both cell types produced antiviral responses and beefed up their defenses against oxidative stress. Viral activity usually puts oxidative stress, a kind of chemical damage, on the cells they attack — so such a reaction should help them weather the invasion. Nasal cells showed the strongest antiviral response, while bronchial (deeper respiratory system) cells exhibited the strongest oxidative resistance of the lot.


Image credits Pearson Scott Foresman.

Excellence comes at a cost, however: the team also found that cells can act against oxidative stress or viruses, but not both at the same time. This was particularly interesting as inhaled irritants — for example cigarette smoke or tree pollen — also generate oxidative stress on cells, the team explains.

Nasal cells exposed first to cigarette smoke and then to rhinoviruses were more vulnerable to the virus’ effects, the team reports.

“Your airway lining protects against viruses but also other harmful substances that enter airways. The airway does pretty well if it encounters one stressor at a time. But when there are two different stressors, there’s a tradeoff,” says lead researcher Ellen Foxman.

“What we found is that when your airway is trying to deal with another stress type, it can adapt but the cost is susceptibility to rhinovirus infection. [The cells] survive the cigarette smoke but can’t fight the virus as well. And the virus grows better.”

Foxman says their study underscores a mechanistic link between environmental exposure and our body’s ability to resist the common cold. The findings also help explain why smokers tend to be more susceptible to rhinovirus infections.

The team hopes their efforts will lead to the discovery of new strategies to combat respiratory viruses, which cause an estimated 500 million colds and 2 million hospitalizations in the United States per year.

The paper has been published in the journal Cell Reports.


Common cold vaccine patented in the EU

Notoriously impervious to anything science has thrown at it sans chicken soup, the common cold may finally have found its match. An Austrian scientist has registered a patent for a vaccine against the disease. He hopes the cure will reach markets in less than a decade.


Rhinovirus in its most adorable form — a plushie.
Image credits Patrick Quinn-Graham / Flickr.

The common cold is treated less like a disease nowadays and more as nuisance — you hope not to get it, and if you do you just wait two weeks for it to go away. Two horrible weeks of a runny, stuffy nose, aching head, and used tissues. You wait it out because there is no cure.

Maybe we don’t need to cure it, but prevent it. Rudolf Valenta, an Austrial allergy expert at the Medical University of Vienna, has spent decades working on exactly that, and has recently registered a patent for a common cold vaccine with the European Patent Registry.

Buff my immune system please

As Valenta explained for The Independent, the technology behind the product isn’t at all revolutionary. It’s based on the tried and true practice of getting our immune system to alter its response to the virus. The key is how it alters this response against rhinoviral infections — the overwhelming cause for common colds.

Working at the Vienna General Hospital in 2012, Valenta and colleagues examined 59 young patient’s response to rhinovirus infections. They found that the human immune system fights the viruses by attempting to stick antibodies on them — which then act as beacons for white blood cells to come in and murder the things. Its main strategy is to go for the virus’ genetic material by breaking the outer shell. The problem is that our immune system is laughably bad at this.

First off, the areas these antibodies attach onto (called epitopes) only becomes exposed once the virus’ outer shell is peeled away. The second problem is that the epipope most antibodies are hell-bent on tying to is ‘non-neutralising’ — meaning that the antibodies don’t do anything here. And thirdly, there are some 99 recorded strains of human rhinovirus (so there are probably a lot more), and they’re all very good at mutating away from what our immune system is targeting at the time. So not only is our body effectively shooting nerf pellets at the wrong part of the target, but the target keeps moving.

All in all, we’re just really, really bad at fighting off colds naturally. Valenta’s vaccine teaches our immune system to go for the shell instead. This, he claims, solves the biggest issue with curing or preventing colds — the sheer variety of rhinoviruses.

“In addition to strain variability, which may prevent protection against rhinovirus infections, we propose misdirection of antibody responses against rhinovirus as a potential novel mechanism of how rhinovirus may escape protective immunity in humans,” the paper reads.

“We’ve taken pieces of the rhinovirus shell, the right pieces, and attached it to a carrier protein. It’s a very old principle, to refocus the antibody response,” Valenta told The Independent. “The diversity [of strains] is less of an issue than getting the right spot on the virus.”

The patent application lists more than 200 papers as a basis for the technology. There are also more than 12 co-authors alongside Valenta (the lead inventor of the vaccine) who have assisted in the vaccine’s development.

“Based on our results, it should be possible to engineer vaccines that allow the redirecting of antibody responses against neutralising rhinovirus epitopes and to treat rhinovirus-related diseases, such as common cold and exacerbations of asthma and chronic obstructive pulmonary disease (COPD).”

A grain of salt

Having a patent ready doesn’t mean that the vaccine will work. And if it does, it’s not a guarantee that it’s the best solution out there. Valenta is optimistic at this stage, but we’ll have to wait and see if the technology pays off. If the trials are successful, however, we could expect to see it on shelves in under a decade, he hopes.

“With the first protein we built, we have very good inhibition [of the disease] already. We believe that we are on a really good track with what we’re doing,” he told The Independent.

“If we get also the trial funded properly, it could be done between six to eight years. We know how to build the vaccines and get it to the clinic. This is really in reach.”

Until then, stack up on chicken soup.

The full paper “Misdirected antibody responses against an N-terminal epitope on human rhinovirus VP1 as explanation for recurrent RV infections” has been published in the journal FASEB.

common cold

Did the vaccine for the common cold just had to include all rhinoviruses? Why didn’t you say so!

common cold

Credit: Flickr user Allan Foster

The common cold might not be cancer, but it’s sure is annoying. In the United States alone, doctors estimate one billion cases of the cold are recorded. For decades, scientists have been trying to come up with a vaccine that would neutralise the sore throat and running nose causing disease which is primarily triggered by rhinovirus infection.

The problem is that there are over 100 identified rhinoviruses and making a vaccine against one virus is rendered useless because there’s a whole armada out there. A team of researchers at the Emory University School of Medicine think they know how to make a common cold vaccine work, though. Their solution is simple: make a vaccine with all the rhinoviruses you can carry.

The first common cold vaccine was made in the 1960s. Back then, researchers showed it was possible to vaccinate people and prevent them from getting sick when put in contact with the virus. It only worked against a single strand of rhinovirus, though — the one they also placed in the vaccine. The sheer number of rhinoviruses circulating all around us has made a lot of scientists abandon hope that a common cold vaccine is feasible.

[panel style=”panel-warning” title=”How to reduce the risk of getting a cold” footer=”source: CDC.gov”]- Wash your hands often with soap and water. f soap and water are not available, use an alcohol-based hand sanitizer. Viruses that cause colds can live on your hands, and regular handwashing can help protect you from getting sick.
– Avoid touching your eyes, nose, and mouth with unwashed hands
– Stay away from people who are sick [/panel]

Emory University researchers, however, applied a simple straightforward solution to a seemingly complicated problem. They made a mixture of 25 types of inactivated rhinovirus, then injected them in 25 mice. They also made a mixture of 50 types of such viruses and injected them in rhesus macaques.

In response to the vaccine, both mice and monkeys created antibodies which later proved to prevent the virus from infecting human cells cultured in a dish.

“We think that creating a vaccine for the common cold can be reduced to technical challenges related to manufacturing,” says Martin Moore, associate professor of pediatrics at Emory University School of Medicine.

“It’s surprising that nobody tried such a simple solution over the last 50 years. We just took 50 types of rhinovirus and mixed them together into our vaccine, and made sure we had enough of each one,” Moore says. “If we make a vaccine with 50 or 100 variants, it’s the same amount of total protein in a single dose of vaccine. The variants are like a bunch of slightly different Christmas ornaments, not really like 50 totally different vaccines mixed.”

The researchers, however, could not test to see whether the animals themselves got sick because there isn’t any reliable animal model for rhinoviruses. Instead, the next thing the researchers plan to do is start a clinical trial with human subjects, something which is deemed feasible considering the non-pathological nature of the common cold. And if the results are confirmed in humans, then millions of sore throats will be made much happier in those cold winter nights.

Findings appeared in Nature Communications.


The average adult catches a flu only twice a decade

Sick, got the flu? Well, maybe what you think is the flu really isn’t the flu… a new study has found that while children catch a flu once every two years on average, the rate goes down significantly in adults – the average adult only gets it once every 5 years.

Image via NY Post.

The flu is any infectious disease caused by the influenza virus. Common symptoms include a high fever, runny nose, sore throat, muscle pains, headache, coughing, and feeling tired, with the cough usually lasting a long time. The flu shouldn’t be mistaken for the common cold though – while it may have similar (typically milder) symptoms, the common cold is not caused by the influenza.

Many people think they got a flu, but as this new study found, that’s most likely not the case. Dr. Adam Kucharski from the London School of Hygiene and Tropical Medicine concluded that most of the time, symptoms attributed by patients to the flu are actually just the common cold.

Dr Adam Kucharski said:

‘There’s a lot of debate in the field as to how often people get flu, as opposed to flu-like illness caused by something else. These symptoms can sometimes be caused by common cold viruses.’

He and his team analyzed blood samples from 151 volunteers from China between the age of seven and 81 and looked at all strains of influenza. It’s the first time this type of study was done (on influenza) and may help us understand how the infectious disease spreads.

They found that we are most vulnerable to flu in our early years, but as we start to grow, we develop antibodies to fight flu viruses by targeting proteins on the virus surface.

Co-researcher Dr Steven Riley said people often simply misuse the word ‘flu’. He said:

‘People don’t mean flu when they say “flu”. What they mean is that they have a bad respiratory illness and there are quite a few of these around.’

You can read the entire article for free, on PLoS.

Biomarker explains why some people catch colds more often than others

Researchers from the Carnegie Mellon University have identified a biological marker in the immune system that (starting from about age 22), predicts the probability of getting a common cold.

telomereThey found that telomeres play a big part in this likelihood. Telomeres are regions of repetitive nucleotide sequences at each end of a chromatid, which protect the end of the chromosome from deterioration or from fusion with neighboring chromosomes. Telomeres are alsoa biomarker of aging, with telomeres shortening as you advance in age. As a cell’s telomeres shorten, it loses its ability to function normally. Basically, shorter telomeres make you more susceptible to a number of diseases, such as cancer or cardiovascular disease – especially in older people. However, as it turns out, it plays a big role in younger adults, and has a tight connection with the common cold as well.

“Our work suggests the possibility that telomere length is a relatively consistent marker across the life span and that it can start predicting disease susceptibility in young adulthood,” said Sheldon Cohen who conducted the study, the Robert E. Doherty Professor of Psychology in CMU’s Dietrich College of Humanities and Social Sciences. “We knew that people in their late 50s and older with shorter telomeres are at a greater risk for illness and mortality. We also knew that factors other than aging, such as chronic stress and poor health behaviors, are associated with shorter telomeres in older people. Consequently, we expected that younger people would vary in their telomere length as well and wanted to see what this would mean for their health.”

He and his team measured the telomere length of white blood cells from 152 healthy volunteers aged 18-55 – inviduals who had been previously exposed to a rhinovirus, which causes a common cold, and quarantined for five days to see if they developed the cold.

The results clearly showed that that particpiants with shorter telomeres were much more likely to become infected with the virus. There was no connection to telomere length and this occurence in people 21 or younger, but after 22 years, telomere length started to predict whether individuals would develop an infection. As participant age increased, telomere length became an even stronger predictor; one telomere especially, of a specific white blood cell (a CD8CD28- T-cytolytic cell) was a superior predictor of infection and cold symptoms than other white blood cell types.

sheldon cohen“These cells are important in eliminating infected cells and those with shorter telomeres in the CD8CD28- cell population may be at greater risk for infection because they have fewer functional cells available to respond to the [cold] virus,” Cohen said. “The superior ability of CD8CD28- T-cytolytic cells to predict infection gives us an idea of which cells to focus on in future work on how telomere length influences the immune system’s response to infection and other immune-related challenges.”

Cohen then added:

“The increased importance of telomere length with age is likely because the younger participants had fewer very short telomeres, or that their young immune systems were able to compensate for the loss of effective cells.”

It has to be emphasized however that these are just the preliminary results, and much more research has to be conducted to clarify the implications of such an association.

The research was published in the Journal of the American Medical Association (JAMA)