The recent antibody surveys in NY state show similar COVID prevalence among younger and older people. E.g., 13% in the age group 35-45 had antibodies, and also in the age group 75+. This raises a disturbing question: 1/7
Natural differences in transmission rates should lead to significant variation in infection rates with age, since younger people empirically have more possible transmission events per day, on average. Mitigations affect these contact patterns, however: 2/7
If mitigations more sharply curtail interactions among younger people than older people (by closing schools, bars, etc.) then the expected result is a shift in the distribution of infection to be more uniform among age groups, rather than shifted towards younger people... 3/7
This increases the IFR above what would be expected when younger people (due to their greater interaction rates) bear a greater burden from infection.
IF a vaccine is around the corner, we shouldn't be worried by this as lot. HOWEVER, 4/7
IF a vaccine is around the corner, we shouldn't be worried by this as lot. HOWEVER, 4/7
IF this is a long haul, and NYC will eventually end up reaching something like herd immunity through an eventual lack of compliance with mitigations, or simply because compliance proves unsustainable over the long term, THEN this trend means that more people will have died, 5/7
compared with a strategy to reach herd immunity with a focus on affecting the age (and risk) distribution of the final immunity herd. These types of strategies are discussed in our preprint with @ChikinaLab:
arxiv.org/abs/2004.04144 6/7
arxiv.org/abs/2004.04144 6/7
Of course, these antibody surveys are still preliminary and we should interpret them with caution. It is possible to imagine relevant ways in which they could be biased. 7/7
