More Study Urged After 7 Teen Boys Suffer Heart Inflammation After Getting COVID-19 Vaccine On 6/4/21 at 1:20 PM EDT Several teenage boys who experienced non-life-threatening heart inflammation after receiving the second dose of the COVID-19 vaccine have prompted health officials to look into whether the cases could be a rare vaccine side effect in teens and young adults. According to an article published online Friday in Pediatrics, seven teenage boys in the U.S. experienced heart inflammation following the second dose of the Pfizer shot, but more research is required to prove the cases are ...