The effectiveness of Pfizer and BioNTech’s Covid-19 vaccine against infection plummets over several months, dropping from a peak of 88% one month after receiving the two-dose series to 47% six months later. This is what emerges from an observational study published yesterday by the peer-reviewed journal The Lancet. While the two-dose mRNA vaccine‘s effectiveness against infection wanes, its protection against Covid-related hospitalizations persists, remaining 90% effective for all worrying coronavirus variants, including delta, for at least six months, according to the study, which was funded by Pfizer.
The results of this study confirm early reports from the US CDC and Israeli health officials who found that protection against infection falls over several months even though its effectiveness persists in avoiding hospitalizations.