Spring is coming — could high pollen counts fuel COVID infection?
Within the next two weeks, spring allergies could begin to take hold in New Jersey, and although we are in a much different place with COVID-19 than we were a year ago, a leading state allergist and immunologist said the 40% of Americans who claim to have pollen allergies could find themselves at increased risk for contracting the coronavirus.
Last year, the discussion was about how to distinguish warning signs of COVID from symptoms of seasonal allergies. But now that researchers know much more about the SARS-CoV-2 virus, they can say more with confidence about the relationship between COVID and pollen, said Dr. Leonard Bielory with the Rutgers Center for Environmental Prediction.
A study co-authored by Bielory, published in the journal Proceedings of the National Academy of Sciences, took data from 31 countries across five continents, some of it from pollen counting stations Bielory supervises. He said it began as an exploration of children who developed pollen allergies and asthma after being afflicted with a bronchial condition from respiratory syncytial virus.
The researchers' theory, which proved true, was built off the inverse of that relationship: Pollen exposure weakens the immune system against respiratory viruses, sometimes working in concert with humidity and temperature to drive up infection risk.
"Under certain favorable weather conditions, it appears that the pollen coincides with events that promote viral infection," Bielory said, adding that while there was no reason for excessive panic, "when you have allergies, you may have an increased propensity to develop an infection with COVID-19."
Bielory said there is no evidence that pollen grains themselves are carriers of SARS-CoV-2, similar to how the notion that mosquitoes might be spreaders was debunked last spring. But the research found a 4% increase in chance of infection for every 100 pollen grains within a cubic meter of air.
"It primes the mucosal surface to become a target, a landing pad, for COVID-19," Bielory said.
There are two glimmers of hope for the pollen-afflicted, according to Bielory.
First, he and his research team have found that once someone has received the COVID-19 vaccine, the correlation with allergies drops to zero. In other words, being particularly sensitive to pollen does not diminish the effectiveness of a vaccine, or increase the chances you will be infected even if protected.
But if you have not yet gotten your shot, he said, the second point is that mask-wearing serves the same purpose against pollen that it does against the coronavirus.
"It will decrease the inhalation of pollen and will decrease the inhalation of viral particles, so actually, in this regard, the use of masks has a double protective effect," Bielory said.