According to a new pre-print study, boys between the ages of 12 and 15, with no underlying medical conditions, were four to six times more likely to be diagnosed with vaccine-related myocarditis than they were to be hospitalized with COVID.
The researchers identified a total of 257 cardiac adverse events (CAE) using inclusion criteria that met the Centers for Disease Control and Prevention (CDC) working case definition of myocarditis.
The post-vaccination CAE rate was highest in 12- to 15-year-old boys following their second dose of Pfizer.
Dr. Tracy Høeg, physician, epidemiologist and associate researcher at UC Davis, found the rate of myocarditis after two doses of Pfizer’s vaccine to be 162.2 cases per million for healthy 12- to 15-year-old boys, and 94 cases per million for healthy 16- to 17-year-old boys. The equivalent rates for girls were 13.4 and 13 cases per million, respectively.
At current U.S. infection rates, the risk of a healthy adolescent being taken to the hospital with COVID in the next 120 days is about 44 per million, they said.
Most children who experienced myocarditis had symptoms within days of the second dose of Pfizer’s vaccine, though a similar side-effect was seen with Moderna’s COVID vaccine.
About 86% of the boys affected required hospital care, the authors said.
“Further research into the severity and long-term sequelae of post-vaccination CAE is warranted,” the researchers concluded. “Quantification of the benefits of the second vaccination dose and vaccination in addition to natural immunity in this demographic may be indicated to minimize harm.” The study has yet to be peer-reviewed.
According to The Guardian, Saul Faust, professor of pediatric immunology and infectious diseases at the University of Southampton, said the findings appeared to justify the cautious approach on vaccines for teens taken by the UK’s Joint Committee on Vaccines and Immunisation (JCVI).
The JCVI did not recommend vaccinating healthy 12- to 15-year-olds against COVID, but referred the matter to the UK’s chief medical officers who said they would consider other factors in recommending the vaccine.
The officials said it was not possible to quantify to what extent vaccination would reduce school disruption. They acknowledged current COVID vaccines are less effective against the Delta variant compared to previous variants.
According to the most recent data from VAERS there have been of myocarditis and pericarditis in 12- to 17-year-olds, with 462 cases attributed to Pfizer’s vaccine.
There have been 4,524 total reports of myocarditis and pericarditis in all age groups with 3, 273 cases attributed to Pfizer and 1,124 cases attributed to Moderna.