The US Food and Drug Administration will add a warning to the Covid vaccines produced by Pfizer/BioNTech and Moderna about rare cases of heart inflammation in adolescents and young adults, the agency announced on Wednesday.
US Centers for Disease Control and Prevention advisory groups, meeting to discuss reported cases of the heart condition after vaccination, found the inflammation in adolescents and young adults is likely linked to the vaccines, but that the benefits of the shots appeared to clearly outweigh the risk.
Health regulators in several countries have been investigating whether the Pfizer/BioNTech and Moderna shots using new mRNA technology present a risk and, if so, how serious.
The CDC said that patients with heart inflammation after vaccination generally recover from the symptoms and do well.
The US Department of Health And Human Services, joined by leading US doctors groups and public health officials, put out a statement underscoring that the vaccines are safe and effective and that the heart side-effect is “extremely rare”.
“We strongly encourage everyone age 12 and older who are eligible to receive the vaccine under Emergency Use Authorization to get vaccinated,” it said.
Doctors and hospitals have been warned by the CDC to watch for symptoms of myocarditis or pericarditis, and the FDA warning will further raise awareness.
Concerns about the more highly transmissible Delta coronavirus variant taking hold in the US, and its impact on younger people, have added to the urgency to increase vaccinations even as the inoculation effort here has slowed considerably.
The European Centre for Disease Prevention and Control (ECDC) said on Wednesday that the more contagious Delta variant, first identified in India, will represent 90% of all Covid-19 viruses circulating in the European Union by the end of August. The announcement echoed a similar warning by the World Heath Organization last week which said the variant was becoming dominant globally.
The number of Americans receiving their first dose of the vaccine is down about 85% since peaking in mid-April, and will probably fail to meet Joe Biden’s goal to have delivered at least one shot to 70% of adults by 4 July.
Pfizer, whose vaccine has been authorized for use in Americans as young as 12, previously said it had not observed a higher rate of heart inflammation than would normally be expected in the general population.
Moderna said it is aware of reports of heart inflammation cases following administration of mRNA vaccines. It said it is working with public health and regulatory authorities to assess the issue.
The CDC has been investigating heart inflammation cases mainly in young men for several months. The Israeli health ministry earlier this month said it saw a possible link between such cases and Pfizer’s Covid vaccine.
The CDC said it was still assessing the risk from the condition and did not specifically confirm a causal relationship between the vaccines and the heart issue.
It did, however, say that a much-higher-than expected number of young men between the ages of 12 and 24 have experienced heart inflammation after their second vaccine dose.
According to data from the US Vaccine Adverse Event Reporting System (VAERS), there were 347 observed cases of heart inflammation in the week after the second vaccine dose in males aged 12 to 24. That compares with expectations of 12 or fewer cases for males in that age range based on US population background incidence rates, the CDC said.