Cancel my order for 200 million COVID-19 vaccine booster shots?
“Are We Jumping the Gun on COVID Boosters?” (MedPage Today, August 24, 2021):
Diminishing vaccine effectiveness supposedly makes the case for boosters. But there are two big questions here: First, what is current vaccine effectiveness? And second, what justifies boosters? Let’s consider these in turn.
We have to be honest, many vaccine effectiveness studies are poorly done. All studies compare the rate of getting a breakthrough infection among vaccinated people against the rate of infection in unvaccinated people. But there are some issues with this approach. First, as time goes on, more unvaccinated people have had and recovered from COVID-19 (and these individuals may be less likely to go on to get a shot). This means that their risk of getting COVID-19 a second time is far less than the typical unvaccinated person who has never been sick. Even if vaccines “work” as well as before, this factor alone will result in the appearance of diminishing vaccine effectiveness.
Second, the order of vaccination in all nations is non-random. The folks who got vaccinated first are often the oldest and most vulnerable people with frailty and senescent immune systems. Vaccine effectiveness after 6 months, 8 months, and 12 months increasingly compares older, frailer people who got vaccinated first against unvaccinated people. These older people may always have a slightly higher risk of breakthrough infections. This bias will also give the false appearance of diminishing vaccine effectiveness.
Humans are terrible at reasoning from statistics. Will our booster shot mania prove to be another example of this phenomenon?
Separately, I do wish someone would explain to me the mania for trying to coerce all of the unvaccinated into #AcceptingScience. We know that the vaccines we have don’t prevent infection or transmission. Our hospitals have plenty of capacity if we’re willing to do a little geographic load-balancing. Maybe an individual should care whether he/she/ze/they gets vaccinated. But why do his/her/zir/their neighbors care if he/she/ze/they gets vaccinated? We now know that the pandemic would not end even if 100 percent of humans were vaccinated.
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