12.6 reported cases of heart inflammation per million second doses given, U.S. data shows
A U.S. Centers for Disease Control and Prevention (CDC) advisory group now says reports of heart inflammation in people given an mRNA-based COVID-19 vaccine are likely linked to the vaccine, but that the benefits of vaccination still outweigh any risks.
In a Wednesday presentation, the CDC's Advisory Committee on Immunization Practices (ACIP) noted that early data from its database shows a rate of 4.4 reported cases of heart inflammation per million first doses given of any mRNA vaccine in the 21 days following vaccination.
That rate jumped to 12.6 reported cases per million second doses.
The reports were greater than anticipated, particularly after dose two in younger age groups, with early data on cases among 12- to 39-year-olds suggesting the case rate is higher in males than females.
During the presentation, Dr. Matt Daly — chair of the ACIP COVID-19 vaccines working group — emphasized the strength of the U.S. vaccine safety monitoring system.