In an earlier study, we had observed an inverse correlation between death rates due to COVID-19 and influenza, suggesting cross-immunity We examine virus surveillance data further to identify the key subtype of influenza virus that seems to give such crossimmunity This is identified as the H1N1 strain and we show that a country where this strain was recently dominant has much lower COVID-19 mortality rates It is possible to argue that many countries which already have a high burden of influenza and pneumonia-related deaths, may have a substantial fraction of the population immune to the SARS-CoV-2 virus and hence experience lower mortality rates at the peak typical of exponentially growing epidemics This has implication on policies appropriate for managing the epidemic © 2020, Indian Academy of Sciences
The H1N1 factor and inverse correlation between death rates due to COVID-19 and influenza-pneumonia