The second dose of Pfizer-BioNTech Covid-19 vaccine will more likely result in the hospitalisation of healthy young people with a rare side effect than the virus itself, a new study says. US investigators investigated the rates of 12-15 and 16-17-year old post-vaccination cardiac myocarditis cases in order to analyse the adolescent advantages and the risk of administering mRNA vaccine.
The researchers identified a total of 257 vaccine-related cardiac adverse events (CAEs) following the second dose of the mRNA vaccine. The rate of the CAEs per million among 12-15-year-old boys was 162.2, while it was 94.0 in 16-17-year-old boys. Among girls, the equivalent rates were 13.0 and 13.4 per million respectively.
The study suggests that the rate of CAE was 3.7 to 6.1 times higher among healthy 12-15-year-old boys than their risk of hospitalisation from Covid-19 in 120 days as of August 21. The rate of CAE was 2.6-4.3-fold higher at times of high weekly hospitalization risk, such as during January 2021.
“For boys 16-17 without medical comorbidities, the rate of CAE is currently 2.1 to 3.5 times higher than their 120-day Covid-19 hospitalization risk, and 1.5 to 2.5 times higher at times of high weekly Covid-19 hospitalization,” the study says.
The study is yet to be peer-reviewed and currently available on a pre-print server.
The United States had issued a warning to watch the symptoms of myocarditis after a small number of heart inflammation cases were reported in adolescents. While the US has continued administering mRNA vaccines among young teens, the UK’s advisory body on vaccination has not recommended inoculating all 12-15-year-olds with mRNA vaccines.
The Joint Committee on Vaccination and Immunisation (JCVI) had opined that though the benefits from vaccination are “marginally greater”, there is “considerable uncertainty regarding the magnitude of the potential harms.” The committee further acknowledged that the margin of benefit against risk is “too small” to advise on a universal programme of vaccination for healthy 12 to 15-year-old children.
“As longer-term data on potential adverse reactions accrue, greater certainty may allow for a reconsideration of the benefits and harms. Such data may not be available for several months,” the JCVI said in an independent report.