When Pfizer CEO Albert Bourla said March 13 that all Americans would need a second booster shot, it struck many covid experts as a self-serving remark without scientific merit. It also set off spasms of doubt over the country's objectives in its fight against the coronavirus.
The decision on how often and widely to vaccinate against covid-19 is part science, part policy, and part politics. Ultimately it depends on the goals of vaccination at a time when it's becoming clear that neither vaccines nor other measures can entirely stop the viral spread.
