April
27, 2021
5 min read
This story originally appeared on The Conversation
By Lewis Ziska , Columbia University
Pollen exposure can increase your risk of developing COVID-19, and it’s not just a problem for people with allergies, 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 findings and explains why pollen seasons are getting longer and more intense.
What does pollen have to do with a virus?
The most important conclusion of our new study is that pollen may be a factor in the exacerbation of COVID-19.
A couple of years ago, my co-authors showed that pollen can suppress the way the human immune system responds to viruses. By interfering with proteins that signal antiviral responses in cells lining the airways, it can make people more susceptible to a large number of respiratory viruses, such as the flu virus and other SARS viruses.
In this study, we specifically look at COVID-19. We wanted to see how the number of new infections changed as pollen levels rose and fell in 31 countries around the world. We found that, on average, about 44 percent of the variability in COVID-19 case rates was 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 lockdown cut the increase in half.
This pollen exposure is not just a problem for people with hay fever. It is a reaction to pollen in general. Even the types of pollen that do not normally cause allergic reactions were 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.
When you are outdoors, wear a mask during pollen season. The pollen grains are large enough that almost any mask designed for allergies will work to keep them out. However, if you sneeze and cough, wear a mask that is effective against coronavirus. If you are asymptomatic with COVID-19, all those sneezes increase your chances of spreading the virus. Mild cases of COVID-19 can also be mistaken for allergies .
Why does the pollen season last longer?
As the weather changes, we see three things that specifically relate to pollen.
One is an earlier start to the pollen season. Spring changes are starting earlier and there are global signs of pollen exposure earlier in the season.
Second, the general pollen season is getting longer. The time you are exposed to pollen, from spring, which is mainly driven by pollen from trees, to summer, which is weeds and grasses, and then fall, which is mainly ragweed, is about 20 days longer. long in North America now that it was 1990. As you move toward the poles, where temperatures rise most rapidly , we find that the season is becoming even more pronounced.
Third, more pollen is being produced. Colleagues and I described the three changes in an article published in February.
As climate change pushes pollen counts up, that could result in increased human susceptibility to viruses.
These changes in pollen season have occurred for several decades. When my colleagues and I look back at as many different pollen storage records as we were able to locate since the 1970s, we find strong evidence to suggest that these changes have been occurring for at least the last 30 to 40 years.
Greenhouse gas concentrations are increasing and the Earth’s surface is warming, and that will affect life as we know it . I have been studying climate change for 30 years. It is so endemic to today’s environment that it will be difficult to analyze any medical problem without at least trying to understand whether climate change has already affected it or is going to.
This article was translated by El Financiero . 
Lewis Ziska , Associate Professor of Environmental Health Sciences, Columbia University
This article is republished from The Conversation under a Creative Commons license. Read the original article .