Sponsored by Pfizer (redux) 2023

Verbatim from Pfizer’s own Website

Possible Side Effects:
Myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the lining outside the heart) have occurred in some people who have received mRNA COVID-19 vaccines. Myocarditis and pericarditis following Pfizer-BioNTech COVID-19 vaccines have occurred most commonly in adolescent males 12 through 17 years of age. In most of these individuals, symptoms began within a few days following vaccination. The chance of having this occur is very low. Seek medical attention right away if your child has any of the following symptoms after receiving the vaccine, particularly during the 2 weeks after receiving a dose of the vaccine:
Chest pain
Shortness of breath or difficulty breathing
Feelings of having a fast-beating, fluttering, or pounding heart
Additional symptoms, particularly in children, may include:

Fainting
Unusual and persistent irritability
Unusual and persistent poor feeding
Unusual and persistent fatigue or lack of energy
Persistent vomiting
Persistent pain in the abdomen
Unusual and persistent cool, pale skin
Fainting can happen after getting injectable vaccines, including Pfizer-BioNTech COVID-19 Vaccine. For this reason, your vaccination provider may ask you to stay at the place where you received the vaccine for monitoring after vaccination.