The effectiveness of the Pfizer-BioNTech vaccine in adolescents

The Pfizer-BioNTech vaccine is based on mRNA technology (see news-COVID-19 newsletter January 25-31 2021), providing our bodies with the code for the SARS-CoV-2 spike (S) surface protein. After injection, the mRNA acts as a matrix for the production of the S protein by our cells. Antibodies and memory lymphocytes targeting the S protein are thereby produced by our immune systems. The vaccine has been proven to be harmless, and has shown 95% effectiveness in patients aged over 16. A recent American study has shown that it could be just as effective and safe in adolescents.

The researchers vaccinated 1 131 participants in the United States aged between 12 and 15 years old with 2 doses of the Pfizer-BioNTech vaccine, with an interval of 21 days between injections, and 1 129 participants with a placebo. In terms of the vaccine’s safety, only slight or moderate side-effects were noted, such as pain at the injection site, fatigue, or head-aches. Regarding its effectiveness, there was an immune response in these adolescents as strong as in adults. In addition, no cases of infection occurring 7 days after the second injection were observed. On the other hand, there were 16 cases of infection in participants who had received the placebo. The vaccine’s effectiveness was therefore 100%.

This study allowed the Pfizer-BioNTech vaccine to become the first to be authorised for use with adolescents. If we wish to achieve adequate herd immunity, it is essential that young people should also be vaccinated.