A panel of experts convened by the top US health agency will hold a meeting Wednesday to review data surrounding more than 300 confirmed cases of heart muscle inflammation among adolescents and young adults after receiving mRNA Covid vaccines. While 300 out of 20 million is a small number, it is still likely higher than what would otherwise be expected for the age group. The new CDC hearing will dive deeper into updated data that has been independently verified, rather than being self-reported. The Pfizer vaccine is currently the only shot authorized in adolescents aged 12 and up. Even if a causal link to the vaccines is established, Rubin said it should be weighed against the risks to children from Covid.