The 1918 “Spanish” flu pandemic killed upwards of 50 million people worldwide. Of the half-million estimated deaths in the U.S., 92% were under 65, and a full half were between 20 and 40 years old.
The best theory for this selective impact comes from a research group at the University of Arizona, who note that this cohort was exposed to a virus with related properties that circulated around 1900, when they were children that (instead of protecting them) primed their immune systems to respond to the later virus in an inappropriate and damaging fashion. Older people severely affected by COVID-19 also exhibit such immune hyper-reactivity, suggesting that they may have been primed by a pathogen exposure in the 1950s, before the less vulnerable population was born.Stuart A. Newman, “Getting Viral: Why COVID-19 is Such a Threat to the 60+ Plus Population and Why the Response May Make It Worse” at CounterPunch
Maybe viral “cold case” detective work will become a new specialty. Newman agrees that seniors should avoid public gatherings but doesn’t think mass quarantine of the entire population is the best strategy because it prevents/delays the development of herd immunity.
See also: Friends point us to this handy science-friendly summary of what is known about COVID-19 as a virus. Updated on an ongoing basis.
Note: Also watch for Jonathan Bartlett’s series coming up on how to set up online meetings (without the nerd who doesn’t want to come to your place just now anyway).