Goldberg Y, Mandel M, Bar-On YM, et al. - Researchers herein sought to report on the extent of waning immunity of BNT162b2 vaccine against the delta variant in Israel.

• From an Israeli national database, researchers retrieved data on confirmed infection and severe disease for the period of July 11 to 31, 2021, for all Israeli residents who had been fully vaccinated before June 2021.

• Among persons 60 years of age or older, persons who became fully vaccinated in January 2021 (when they were first eligible) had a higher rate of infection in the July 11–31 period relative to those fully vaccinated 2 months later, in March.

• Among persons 40 to 59 years of age, those fully vaccinated in February (when they were first eligible) had infection rate ratio of 1.7, when compared with those vaccinated 2 months later, in April.

• Among persons 16 to 39 years of age, those fully vaccinated in March (when they were first eligible) had infection rate ratio of 1.6 when compared with those vaccinated 2 months later, in May.

• Compared with persons fully vaccinated in March, those fully vaccinated in the month when they were first eligible had a rate ratio for severe disease of 1.8 among persons 60 years of age or older and 2.2 among those 40 to 59 years of age; the rate ratio could not be calculated among persons 16 to 39 years of age owing to small numbers.

• As per these findings, all age groups had waning of immunity against the delta variant of SARS-CoV-2 a few months after receipt of the second dose of vaccine.