[theold]

Myocarditis, a rare side effect, occurs mostly after the second dose. So in some countries, officials are trying out single doses for children.

Officials in Hong Kong as well as in Britain, Norway and other countries have recommended a single dose of the Pfizer-BioNTech vaccine for children ages 12 and older — providing partial protection from the virus, but without the potential harms occasionally observed after two doses.


https://www.nytimes.com/2021/10/06/healt...-dose.html