Bates TA, Leier HC, Lyski ZL, et al. - Reportedly, 95% protection from COVID-19 is provided by vaccination with 2 doses of the BNT162b2 vaccine (Pfizer-BioNTech).

• Researchers herein examined how age is linked with neutralizing antibody titers against the early SARS-CoV-2 USA-WA1/2020 strain and the P.1 variant of concern after 2 doses of the BNT162b2 vaccine.

• Serum samples were obtained from participants prior to receipt of the first dose and 14 days after receipt of the second dose of the BNT162b2 vaccine.

• All participants showed robust neutralizing responses against the original strain (USA-WA1/2020), with a geometric mean titer (GMT) serum dilution of 393.

• There were lower responses against the P.1 variant, with a GMT of 91, representing a 76.8% reduction; the age-dependent difference was smaller in magnitude.

• A negative association of initial vaccine-elicited neutralizing antibody titers with age was observed, resulting in a reduced ability to neutralize SARS-CoV-2 in vitro.

• Age is not identified as a contributing factor to overall vaccine efficacy in interim clinical trial data analysis.

• However, vaccinated older adults had a measurable increase in COVID-19 cases among vaccinated populations in recent studies; the data from the current study support an important role of neutralizing antibody levels in this observation.