New Delhi: A study assessing the immunogenicity and efficacy of the Pfizer-BioNTech vaccine on 12-15 year olds found that it was safe and had an observed efficacy of 100 per cent.
The study, published in the New England Journal of Medicine on 27 May, was conducted on 2,260 adolescents aged between 12 and 15 years, of which 1,131 received the vaccine (BNT162b2), and 1,129 received placebo. The study was funded by Pfizer and BioNTech.
“A two-dose regimen…administered 21 days apart to adolescents 12 to 15 years of age was safe and immunogenic and resulted in an observed vaccine efficacy of 100% against Covid-19 from 7 days after dose 2,” the study said.
The study was conducted in the US, which had already opened up vaccinations for adolescents above the age of 12 in mid-May, after the Centre for Disease Control approved the Pfizer vaccine for this age group.
Chile, Canada, Japan and Italy are among the other countries to have approved the Pfizer vaccine for adolescents above the age of 12. The Philippines and Dubai have approved this vaccine for emergency use.
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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 (58 per cent) had at least two months of follow-up after their second vaccine dose.
The vaccine’s reactogenicity (the degree to which a vaccine can produce 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 16 to 25 years.
“In both age cohorts, headache and fatigue were the most frequently reported systemic events. After BNT162b2 injection, severe headache and severe fatigue were reported in a lower percentage of 12-to-15-year-old participants than of 16-to-25-year-old participants,” said the study, adding, “The immune response to BNT162b2 in 12-to-15-year-old adolescents was noninferior to that observed in 16-to-25-year-old young adults.”
Among participants without evidence of previous SARS-CoV-2 infection, no Covid-19 cases with an onset of seven or more days after dose 2 were noted among BNT162b2 recipients, and 16 cases occurred among placebo recipients. The observed vaccine efficacy was 100 per cent, said the study.
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