More severe effects were exceedingly rare. Out of about 8.7 million vaccinations delivered during the study period, 100 such reports were received by VAERS. They included 29 reports of fever, 21 reports of vomiting, and 10 serious reports of seizure, although in some of these seizure cases, other underlying factors were potentially involved, the CDC team said.
There were only 15 "preliminary reports" of the rare heart condition known as myocarditis, an inflammation of the heart that has also been noted, in rare cases, among teens and young people who've received the COVID vaccine.
Two girls, aged 5 and 6, who'd received the Pfizer vaccine died during the study period. Hause and colleagues noted that both children "had complicated medical histories and were in fragile health before vaccination," and they added that "none of the data suggested a causal association between death and vaccination."
Although pediatric deaths from COVID-19 remain rare, hundreds of American children have died from the illness since the pandemic began.
https://www.usnews.com/news/health-news/articles/2021-12-30/real-world-data-confirms-pfizer-vaccine-safe-for-kids-ages-5-11