The Case for Extreme Vaccine Effectiveness
I owe tremendous acknowledgments to Kelsey Piper, Oliver Habryka, Greg Lewis, and Ben Shaya. This post is built on their arguments and feedback (though I may have misunderstood them).
Update, May 13 I first wrote this post before investigating the impact of covid variants on vaccine effectiveness, listing the topic as a major caveat to my conclusions. I have now spent enough time (not that much, honestly) looking into variants that I have a tentative position I'm acting on for now.
My moderately confident conclusion is that the current spread of variants in the US barely impacts vaccine effectiveness. The Pfizer vaccine is reported to be 85% as effective against the feared B.1.351 variant (South African) as it is against B.1.1.7 (UK). Assuming that other variants are no more resistant than B.1.351 on average (a reasonable assumption) and that presently variants are no more than 25% of Covid cases (in Alameda and San Francisco). The net effect is 0.25*0.85 + 0.75*1.0 = 0.9625. In other words, vaccines still have 96% of the effect they would if B.1.1.7 were the only variant.
Plus, that tiny reduction of vaccine effectiveness is dwarfed by the falling background prevalence of Covid. When I first wrote this post, Alameda and San Francisco were at 0.1-0.15%; now they're at ~0.05%. The same for New York and the United Kingdom.
