Is pollen responsible for rise in Covid-19 cases?

As per scientists, as pollen levels increased in outdoor air in 31 countries, the cases of Covid-19 also increased. On the other hand, few others suggested that peaks in pollen seasons coincide with a fall-off in the spread of some respiratory viruses, like COVID-19 and influenza.

But now, a new study published in the Proceedings of the National Academy of Sciences said that when pollen in an area spiked, so did infections, after an average lag of about 4 days. The study authors say pollen seemed to account for, on average, 44% of the infection rate difference between countries.

It took data from 248 airborne-pollen-monitoring sites in 31 countries. The study also took into account other effects, such as population density, temperature, humidity, and lockdown orders.

In a press conference, study author Stefanie Gilles, PhD, chair of environmental medicine at the Technical University of Munich in Germany said, “When we inhale pollen, they end up on our nasal mucosa and here, they diminish the expression of genes that are important for the defense against airborne viruses.”

Hoogeveen’s recent study, published in Science of the Total Environment, found that the arrival of pollen season in the Netherlands coincides with the end of flu season, and that COVID-19 infection peaks tend to follow a similar pattern.

Another study said — as pollen climbs, flu cases drop. The researchers behind that study think pollen may actually compete with viruses in our airways, helping to block them from infecting our cells.

However, there is no strong scientific reason to support these different claims.