Pfizer vaccine shows 100 per cent efficacy in 12-15 year olds: US study

As per a new study published in the New England Journal of Medicine on 27 May, Pfizer vaccines administered 21 days apart to adolescents from 12 to 15 years of age was safe and immunogenic and resulted in an observed vaccine efficacy of 100 per cent against Covid-19 from 7 days after dose 2.

For the study, 2,260 adolescents participated aged between 12 to 15 years, of which 1,131 were given the vaccine (BNT162b2) and 1,129 were given a placebo.

The study was conducted in the US, which has already started the vaccination for adolescents above the age of 12 in mid-May after the Center for Disease Control and Prevention approved the Pfizer vaccine for this age group.

Other countries that have approved the Pfizer vaccine for adolescents above the age of 12 include Chile, Canada, Japan and Italy. Dubai and Philippines have approved the vaccine for emergency use.

The study
Among the 2,260 participants, 51 per cent were male, 86 per cent were White and 12 per cent were Hispanic or Latinx. Overall, 1,308 participants had at least two months of follow-up after their second dose of vaccination.

The vaccine's reactogenicity (the degree to which a vaccine can produce an excessive immune response and adverse reactions) and immunogenicity (the ability to elicit an immune response against a pathogen) was compared with that of another cohort, of people aged between 16 to 25 years.

In both age groups, headache and fatigue were the most commonly reported systemic events.

After BNT162b2 injection, severe headache and fatigue were reported in a lower percentage of 12-15-year-old participants than of 16-25-year-old participants. The immune response to BNT162b2 in 12-15-year-old adolescents was non-inferior compared to 16-25-year-old young adults.

The observed vaccine efficacy was 100 per cent, said the study.