Safety, Immunogenicity, and Efficacy of the BNT162b2 Covid-19 Vaccine in Adolescents

SPS commentary:

A randomised, placebo-controlled Phase III trial of the Pfizer-BioNTech vaccine assessed its safety, immunogenicity and efficacy in healthy persons aged 12 years or older. This report presents the findings from participants aged 12-15 years enrolled in the US, including an evaluation of the non-inferiority of the immunogenicity in this cohort compared to that in the 16-to-25 year old cohort, assessed on the basis of the geometric mean ratio of SARS-CoV-2 50% neutralizing titers, in a random subset of participants (n=225 from each group). 

The geometric mean ratio of the BNT162b2 neutralizing geometric mean titer in 12-to-15-year-old participants to that in 16-to-25-year-old participants 1 month after dose 2 was 1.76 (95% CI 1.47 to 2.10), which met the non-inferiority criterion and indicated a greater response in adolescents than in young adults.

Among the 1983 participants in the 12-to-15-year-old cohort who could be evaluated and did not have evidence of previous SARS-CoV-2 infection, no cases of Covid-19 with an onset of 7 or more days after dose 2 were observed among BNT162b2 recipients versus 16 cases among placebo recipients (vaccine efficacy of 100%; 95% CI 75.3 to 100). The authors note that this analysis was descriptive, as a sufficient number of Covid-19 cases was not anticipated; however the lower limit for vaccine efficacy was above 75% and this provides ‘substantial evidence of efficacy in this age group’.