Federal officials are reviewing nearly 800 cases of rare heart problems following vaccination with coronavirus vaccines made by Pfizer-BioNtech and Moderna. data submitted At a vaccine safety meeting on Thursday.
Not all cases are verified or likely to be related to vaccines, and experts agree that the benefits of vaccination far outweigh the risks of these rare complications. But the reports have worried some researchers. Heart problems were reported in more than half of those aged 12 to 24, while the same age group accounted for only 9 percent of the millions of doses given.
“We clearly have an imbalance there,” said Dr. Tom Shimabukuro, a vaccine specialist at the Centers for Disease Control and Prevention, who presented the data. Agency advisors will meet June 18 to explore possible links to complications: myocarditis, an inflammation of the heart muscle, and pericarditis, an inflammation of the membrane surrounding the heart.
About two-thirds of cases were in young men, with an average age of 30. Officials said the numbers are higher than expected for that age group, but have not yet been definitively linked to vaccines.
As of May 31, 216 people had experienced myocarditis or pericarditis after one dose of either vaccine and 573 after a second dose. Most of the cases have been mild, but 15 patients are in hospitals. The second dose of the Pfizer-BioEntech vaccine was associated with almost twice as many cases as the second dose of the vaccine made by Moderna.
There were 79 reported cases of heart problems among those 16 or 17 years old, compared to the expected maximum of 19 cases for that group. And in the group of youth aged 18 to 24 years, there were 196 cases, against the expected maximum of 83 cases.
But the true incidence may be less, Dr. Shimabukuro said. Vaccination of young adolescents began only last month, and data for that age group in particular are limited.