2. Waning immunity

I was too skeptical of the early signs of waning vaccine immunity and the importance of boosters.

Toward the end of the summer, some researchers began pointing to data suggesting that the power of vaccines waned after about six months. Other researchers doubted that case, saying that the data was unclear — and that pharmaceutical companies had an obvious incentive to promote waning immunity and boosters. But the case for boosters now seems clear.

Amid uncertain evidence, I try to avoid automatically assuming the worst. Often, that’s the right approach. (A lot of early Covid alarmism — about the virus’s effect on children, the contagiousness of Delta and the severity of Omicron, for instance — has proved to be misplaced.) Sometimes, though, the ominous signs are the ones worth heeding.