Original note published in The Conversation
To the Lewis Ziska, Columbia University
Pollen exposure can increase the risk of developing COVID-19 and is not just a problem for allergy sufferers, new research shows. Plant physiologist Lewis Ziska, co-author of the new peer-reviewed study and other recent research on pollen and climate change, explains the results and explains why the pollen season is getting longer and more intense.
What does pollen have to do with a virus?
The main conclusion of our new study is that pollen may be a factor in worsening COVID-19.
A few years ago, my co-authors showed that pollen can suppress the human immune system’s response to viruses. By disrupting proteins that signal antiviral responses in cells that line the airways, people can become more susceptible to large numbers of respiratory viruses, such as the flu virus and other SARS viruses.
In this study, we look specifically at COVID-19. We wanted to see how the number of new infections changes as pollen levels go up and down in 31 countries around the world. We found that, on average, about 44 percent of the variability in COVID-19 fall rates is related to pollen exposure, often in synergy with humidity and temperature.
Infection rates tended to increase four days after a high pollen count. If there was no local blockage, the infection rate increased by an average of about 4 percent per 100 pollen grains in one cubic meter of air. A strict closure halved the increase.
This pollen exposure isn’t just a problem for people with hay fever. It’s a response to pollen in general. Even the types of pollen, which do not normally cause allergic reactions, correlated with an increase in COVID-19 infections.
What precautions can you take?
On days with high pollen counts, try to stay indoors to limit your exposure as much as possible.
If you are outdoors, wear a mask during the pollen season. The pollen grains are big enough that almost any mask designed for allergies will keep them away. However, if you sneeze and cough, wear a mask that is effective against coronavirus. If you are asymptomatic with COVID-19, all of these sneezes increase your chances of spreading the virus. Mild cases of COVID-19 can also be mistaken for allergies.
Why is the pollen season longer?
When the weather changes we see three things specifically related to pollen.
One is an earlier start to the pollen season. The spring changes start earlier and there are global signs of pollen exposure as the season begins.
Second, the general pollen season is getting longer. The time you are exposed to pollen, from spring, which is mostly powered by pollen from trees, to summer, which is made up of weeds and grasses, and autumn, which is mostly ragweed, is now about 20 days in North America longer It was 1990. As you approach the poles, where temperatures rise the fastest, we notice that the time of year is becoming even more pronounced.
Third, more pollen is produced. Colleagues and I described the three changes in an article published in February.
If climate change increases pollen counts, it could make humans more susceptible to viruses.
These changes in the pollen season have been occurring for several decades. When my colleagues and I look back on as many different pollen storage records as we have been able to find since the 1970s, we find strong evidence that these changes have been happening for at least 30 to 40 years.
Greenhouse gas concentrations are increasing and the earth’s surface is warming. This affects life as we know it. I’ve been dealing with climate change for 30 years. It is so endemic in today’s environment that it will be difficult to analyze a medical problem without at least understanding whether climate change has already affected or will affect it.
This article was translated by El Financiero.
Lewis Ziska, Associate Professor of Environmental Health Sciences, Columbia University
This article is republished by The Conversation under a Creative Commons license. Read the original article.