The New England Journal of MedicineSix-Month Follow-up After a Fourth BNT162b2 Vaccine Dose

In a recently published prospective cohort study, a third dose of the BioNTech Pfizer vaccine yielded a sustained immunologic response. But response to a fourth was much smaller and was gone completely by 13 weeks, providing only a short-term benefit over the third dose. A fourth dose should therefore be timed based on disease waves or be provided seasonally, like the influenza vaccine.