The human factor between airborne pollen concentrations and COVID-19 disease dynamics

In their seminal paper, Damialis and colleagues (2021, PNAS) report that, in early 2020, higher airborne pollen concentrations were related to higher COVID-19 infection rates. As a mechanism, the authors propose that “pollen exposure weakens the immunity … by diminishing the antiviral interferon response.” Although they assume an effect for the whole population, they speculate that it could be stronger for those with allergies. As a limitation, they acknowledge that they did not account for the countries’ testing strategies. As allergic people may be more likely to show symptoms that may be mistaken for those of COVID-19 (runny nose, headache, increased temperature), we explored whether people with allergies were more prone to get a rapid SARS-CoV-2 antigen test. Moreover, we assessed whether the test result was more likely to be positive among those with allergies.