Pfizer Covid shot protects people from hospitalization even as effectiveness against infection falls, Lancet study confirms

The effectiveness of Pfizer and BioNTech’s Covid-19 vaccine against infection tumbles over several months, falling from a peak of 88% a month after receiving the two-shot series to 47% six months later, according to an observational study published Monday in the peer-reviewed journal The Lancet.

While the two-dose mRNA vaccine’s efficacy against infection wanes, its protection against Covid-related hospitalizations persists, remaining 90% effective for all coronavirus variants of concern — including delta — for at least six months, according to the study, which was funded by Pfizer.

The findings confirm early reports from...