Six-Month Follow-up after a Fourth BNT162b2 Vaccine Dose

Abstract

T h e ne w e ngl a nd jou r na l o f m e dicine n engl j med 387;22 nejm.org December 1, 2022 sustained immunologic response as compared with two doses, but the additional immunologic advantage of the fourth dose was much smaller and had waned completely by 13 weeks after vaccination. This finding correlated with waning vaccine effectiveness among recipients of a fourth dose, which culminated in no substantial additional effectiveness over a third dose at 15 to 26 weeks after vaccination. These results suggest that the fourth dose, and possibly future boosters, should be timed wisely to coincide with disease waves or to be available seasonally, similar to the influenza vaccine. Whether multi-valent booster doses will result in longer durability remains to be seen.