Will Mortality Rates in the Next Viral Pandemic Be Affected by the COVID-19 Experience?

To the Editor—The article by Harteloh and van Mechelen comparing death rates between the 1918 influenza pandemic and coronavirus disease 2019 (COVID-19) [1] demonstrates the difference between the virulence of influenza virus and severe acute respiratory syndrome coronavirus 2 and public health and medical care available during these pandemics. Another influencing factor that deserves attention is the work by Gagnon et al, who graphically displayed the role of the 1889 Russian flu in greatly increasing the severity of the 1918 flu [2]. It has been proposed that the Russian flu was actually an earlier coronavirus pandemic, but regardless of whether it was or was not, it is very likely that it influenced innate immunity of the generation exposed in 1889 [3]. COVID-19 mortality charts show that the Western population was more affected by COVID-19 than others, suggesting that survival from COVID-19 was not completely related to quality of healthcare but was related to a group of genes on chromosome 3 [4]. These genes, which were inherited from Neanderthal ancestors, are carried by about 16% of the European population that includes most of the White race in the United States. Some of these genes code for a strong inflammatory response, leading to severe disease and higher mortality in those individuals during the COVID-19 pandemic [5]. Subtle changes can occur in patients who have survived COVID-19, even in those who do not suffer from long COVID [6]. Past-lived bodily experience as well as those of our ancestors can affect future immune system responses, as has been noted in descendants of those who survived the plague in Europe in the 14th century [7]. Time will tell if our innate immunity has been altered by COVID-19 and how we will respond to the next pandemic, be it influenza, a coronavirus, or yet another virus. Will history repeat itself? Financial support. None.