Drs. Philip Krause and Luciana Borio are myopic and cavalier about the risks of Covid-19 ("You Likely Don't Need a Fourth Covid Shot," op-ed, March 29). Their discussion of the probability of infection following various vaccination regimes is generally correct, but there is a saying in medicine that for an individual person, the probability of an event such as infection or survival in the population is irrelevant. For that person, the outcome is either zero or 100%.
The significant frequency of long Covid, with its potential long-term debility, and the postinfection increased risk of cardiac disease and changes in the brain argue for a high level of caution. I've gotten the second booster.
Henry I. Miller, M.D.
Redwood City, Calif.
Dr. Miller was a research associate at the NIH and the founding director of the FDA's Office of Biotechnology.