Waning Immune Humoral Response to BNT162b2 Covid-19 Vaccine over 6 Months

Abstract (PubMed)

We conducted a 6-month longitudinal prospective study involving 4868 vaccinated health care workers tested monthly for anti-spike IgG and neutralizing antibodies. Linear mixed models assessed antibody dynamics and predictors at 6 months. IgG decreased at a consistent rate; neutralizing antibody levels decreased rapidly for the first 3 months with slower decrease thereafter. Six months after the second dose, neutralizing titers were substantially lower among men than women, lower among persons ≥65 years old, lower among immunocompromised patients, and lower among persons who received the vaccine during January 2021. These findings may be related to the increase in infections observed in Israel despite high vaccination coverage.