LAUSR

Key Points Question Are neutralizing antibodies against the Omicron variant of SARS-CoV-2 sufficiently induced after 2 to 3 doses of the BNT162b2 messenger RNA vaccine in recipients of different ages? Findings In this cohort study of 82 Japanese participants, 28% and 6% had neutralizing antibodies against the Omicron variant at 2 and 7 months, respectively, after 2 doses of the vaccine; both titer values were low in all age groups. After receiving a booster vaccination, all participants acquired much higher levels of neutralizing antibodies irrespective of age. Meaning This study suggests that booster vaccination was associated with induction of higher levels of neutralizing antibodies against the Omicron variant, irrespective of the recipient’s age.