Tag Archives: Spread

Commuting patterns can help explain why some ethnicities were worse affected by COVID-19

The higher COVID-19 infection rates seen in black American communities compared to the overall averages could come down, at least in part, to their daily commute, a new paper explains.

Image via Pixabay.

We all felt the pressure that the pandemic has placed on our lives, but some of us have been having a way harder time than others. Sure, nobody likes being stuck inside for days on end, but we have to admit that it’s a luxury, and a privilege, for that to be our main gripe in a global pandemic that killed many thousands.

Minorities and poorer communities have borne the brunt of the hardship. We don’t know for sure exactly why, but it’s not hard to intuit how a lack of resources, poor socio-economic prospects, and social marginalization play into this. A new study comes to flesh out our understanding of these mechanisms by uncovering the role daily commuting patterns play in spreading the coronavirus through black American communities.

Working problems

“The study suggests that taking into account daily commuting patterns of a social or ethnic group can be enough to explain most of the differential incidence of COVID-19 in African American communities during the first epidemic wave last year,” says Aleix Bassolas, Postdoctoral Research Assistant at Queen Mary.

The team used US census data from over 130 metropolitan areas to put together two types of geographical network. The connections between bordering census areas, together with commuting graphs, were used to chart the flow of people coming to and from their jobs across the nation. Their results suggest that coming into contact with other ethnic groups at their workplace or during their commute can account for the documented “infection gap” in society.

The higher than average incidence of COVID-19 recorded in black communities can be explained through this mechanism, the team notes. Predominantly-black communities in the US are some of the nation’s poorest and thus hardest-hit by the pandemic. For many of their members, sitting it out in quarantine simply isn’t an option, and they have to take a job outside of the home to keep families fed and rent paid.

In some areas of the U.S., COVID-19 incidence among such communities can be up to 5 times higher than the overall societal average. Previous research has shown that socio-economic factors can explain part of this infection gap, but not all of it.

In their study, the authors considered the effect that residential segregation (that people tend to live in areas where their ethnicity is the majority) and other forms of segregation such as commuting have on spreading or containing the disease. This was mediated by the groups’ diffusion segregation, which estimates how likely any group is to come into contact with groups of other ethnicities. A weekly tally of known COVID-19 cases during the early days of the pandemic was used to test the findings.

Strangers on the train

Random routes were simulated over the commuting graphs the team put together, which aimed to determine how long it would take for a person from a census tract to encounter individuals from another ethnic group for the first time. This approach showed that black Americans were the most exposed to other ethnicities — in essence, they’re the group most likely to come into contact with any of the other groups.

Later on in the pandemic, as restrictions on movement began to be implemented on a larger scale, public transport usage started to correlate strongly with the infection gap observed in different US regions.

The team also notes that diffusion segregation alone could explain the observed infection gap relatively well, while factors such as life expectancy or access to healthcare services had more of an influence on the disproportionately high CODIV-19 death rates seen in black communities.

“Our results confirm that knowing where people have to commute to, rather than where they live, is potentially much more important to curb the spread of a non-airborne disease,” says Dr. Vincenzo Nicosia, Lecturer in Networks and Data Analysis, at Queen Mary and corresponding author of the paper.

“Policymakers need to take into account specific mobility patterns and needs, as well as differences in the mobility and commuting habits of different ethnic and social groups when deciding on the most effective non-pharmaceutical countermeasures against COVID-19 and similar non-airborne diseases.”

The approach used here can easily be applied to other countries such as the UK, but it’s dependent on them having quality, detailed records of commuting data. Not every government has access to those, they explain.

The paper “Diffusion segregation and the disproportionate incidence of COVID-19 in African American communities” has been published in the Journal of the Royal Society Interface.

If there’s any life in the Trappist-1 system it’s likely been planet-hopping, scientists say

If there’s any life in the Trappist-q system, it’s likely that it won’t be limited to only one planet, a study from Harvard University says.

An artist’s impression of planets transiting in front of Trappist-1.
Image credits NASA, ESA, and G. Bacon (STScI) / Wikimedia.

With NASA’s announcement of the seven exoplanets in the Trappist-1 system, three of which lie in the habitable Goldilocks zone and could have liquid water on their surface, the hope of witnessing the discovery alien life got re-ignited for a lot of people.

And we might get more new friends than we’ve thought: a new study published by Manasvi Lingam and Avi Loeb at Harvard University suggests that the habitable planets in the Trappist-1 system are close enough that microbes could hitch a ride from one world to the others via rocks.

Their theory is that when meteorites or other space bodies hit one of these three habitable worlds, the force of the impact could propel material into space which might find its way to one of the neighbors. Microbes sheltering in these chunks of rock could then ‘seed’ life on its new planet, a process referred to as panspermia. It may sound far-fetched, but it’s actually one of the ways we think life could have appeared on Earth — through microbes blown over from Mars in the wake of a huge impact.

Free travel

To test their theory, the team created digital models of how life could move between the planets starting from patterns in species immigration between different islands on Earth. Their results suggest that between the habitable planets in Trappist-1, life has a 1,000 times greater likelihood of transfer compared to that estimated between Earth and Mars. It’s mostly thanks to the fact that the planets are tidally locked in tight orbits around the stars — meaning a short commute for germs between them. Once life settles on one planet, it’s very likely to spread on the others, the authors say.

“These planets are similar to islands on the surface of the Earth, and there are studies of the immigration of species from one island to another,” Loeb explained for Gizmodo.

“We used the same model to illustrate that the likelihood is very high for transfer of life.”

Comparison between the Solar and Trappist-1 systems.
Image credits NASA/JPL-Caltech.

The final check for the theory of panspermia on Trappist-1 will be to find atmospheres around the habitable planets. In the absence of atmospheric cover water won’t stay liquid on the surface, making it unlikely that life could evolve on the planet and almost impossible for it to immigrate from the neighbours. Loeb says that the next order of business is to monitor the planets as they transit in front of the star and measure the dip in light to see if it’s indicative of atmospheres. After that, finding out the atmospheres’ composition to see if they have what we consider the “building blocks of life” — such as oxygen or CO2.

“We can roll the dice three times in this system compared to Earth, which is the only planet where we know life exists in the solar system,” Loeb said. “So at least you have three chances.”

Fingers crossed.

The full paper “Enhanced interplanetary panspermia in the TRAPPIST-1 system” has been published in the journal Astrophysics.