RESULTS
fevers
EVENTS, SARS-COV-2 INFECTION
All 401 enrolled participants received the third (booster) BNT162b2 dose at least 5 months after dose 2 (most commonly between 8 and 9 months after dose 2 [86.8%]) and comprise the safety population (see A third BNT162b2 dose elicited ancestral SARS-CoV-2 neutralizing responses 1 month after dose 3 that were substantially increased versus those 1 month after dose 2, with a GMR of 2.17 (Serum SARS-CoV-2 neutralization titers 1 month after BNT162b2 doses 2 and 3 in participants without evidence of prior SARS-CoV-2 infection. In Panel A, 50% neutralizing titers were determined in a validated microneutralization assay against ancestral SARS-CoV-2 strain (USA-WA1/2020). Results are in the dose 2 and dose 3 evaluable immunogenicity populations (defined in In a subset of participants, Omicron sublineage BA.1 neutralizing GMTs were 28 and 614 at 1 month after dose 2 and 1 month after dose 3, respectively, corresponding to a 22-fold titer increase after the third dose (The third BNT162b2 dose was well tolerated, with a safety profile consistent with previous doses in this age group. No new safety signals were identified. Most reactogenicity events were mild to moderate in severity and transient; no grade 4 events or fevers >40 °C were reported (Local reactions and systemic events. Panel A shows local reactions and Panel B shows systemic events in BNT162b2 recipients with electronic-diary data after dose 1 (Up to 1 month after dose 3, AEs were reported by 9% of participants and no AEs led to withdrawal (