Pfizer Covid-19 Vaccine safe and effective in Adolescents: NEJM study

Adolescents play an important role in SARS-CoV-2 transmission, thus their vaccination may prevent disease and contribute to herd immunity. Researchers from California observed favorable safety and efficacy of BNT162b2 Covid-19 vaccine in 12-16 year old adolescents.

BNT162b2 (Pfizer-BioNtech) is a Covid-19 vaccine containing nucleoside-modifies mRNA encoding SARS-CoV2 spike glycoprotein. This vaccine was approved in Dec 2020 for adults after phase 3 trials globally since the vaccine had favorable safety profile. The COVID-19 pandemic had interrupted education and social development of students and simultaneously burdening the caregivers, hence safe, efficacious vaccines for younger populations are paramount.

Dr.Robert et al in collaboration with Pfizer and BioNtech conducted a randomized trial in healthy individuals aged 12 years and above to assess safety, efficacy and immunogenicity of this vaccine. In the study 2264 participants in the age 12-15 years(cohort 1) and 3788 participants between age 16-25 years of age(cohort 2) were randomized into two subsets in each cohort- one subset who received the vaccine and other subset who received placebo. Persons with previous clinical or virological Covid-19 infection were excluded.

Major findings of the study include:

1. In both age cohorts , injection site pain was the most common local reaction. Severe injection site pain was reported in 1.5% of 12-15 year old participants and in 3.4% of 16-25 year old participants.

2. Headache and fatigue were the most frequently reported systemic events among both age cohorts. In general systemic side-effects were reported more often after BNT162b2 dose 2 than after dose 1.

3. Upon analysis greater immunogenicity to vaccine was observed in adolescents than in young adults as indicated by serum-neutralising geometric mean titer one month after BNT162b2 dose 2 which was 1283.0 in 12-15 year-old cohort and was 730.8 in the 16-25 year-old cohort.

4. Among 1983 participants in the 12-15 years old cohort who could be evaluated for efficacy , no cases of Covid-19 with an onset of 7 or more days after dose 2 was observed; which correspond to observed vaccine efficacy of 100%.

The favourable safety profile from this study is important because a precedent exists for vaccines being more reactogenic when administered to younger people.

Although children generally have a lower burden of symptomatic Covid-19 than adults; schools,youth sports, and other community gatherings may represent important sources of ongoing outbreaks and transmission, despite high rates of adult immunization. Hence, vaccination of adolescents will allow them to reintegrate into society and resume in-person learning safely, which are especially important outcomes given the severe mental health effects of the Covid-19 pandemic on this group.

Authors conclude-"The BNT162b2 vaccine in 12-to-15-year-old recipients had a favorable safety profile, produced a greater immune response than in young adults, and was highly effective against Covid-19".

Source:NEJM