Pfizer and Moderna must revise their Covid-19 vaccine labels to include more detailed warnings about the risks of heart damage, the US Food and Drug Administration (FDA) said on Wednesday.

Letters issued to both companies state that post-marketing analysis shows greater risks than previously indicated for myocarditis or inflammation of the heart muscle, and pericarditis, which refers to inflammation of the sac-like membrane surrounding the heart.

The companies must expand the age group they say is at risk for vaccine-related myocarditis and pericarditis and warn that myocardial injury can be lasting among those who suffer it, the agency said.

Both Covid-19 vaccines’ labels previously warned that the shots posed a risk of post-vaccination myocarditis and pericarditis for young men – Moderna’s Spikevax label specified that 18- to 24-year-olds were at risk, while Pfizer’s Comirnaty warning targeted 12- to 17-year-olds.

The new labels must state that the known rate of myocarditis and pericarditis is about 8 cases per million doses for children and adults under 65 years old. They must also warn that the “highest estimated incidence was in males 16 through 25 years of age,” among whom the rate was 38 cases per million.

Last month, researchers for the Centres for Disease Control and Prevention (CDC) told the agency that acute myocarditis “tends to resolve quickly” after vaccination.

However, the new labelling cites data showing that five months following vaccination, “myocardial injury was common.” The FDA said the vaccine makers must add that information to their labels.

A spokesperson for the U.S. Department of Health and Human Services (HHS) said Wednesday that the labeling change was intended to increase “radical transparency.”

Neither Pfizer nor Moderna responded to request for comment.

The FDA issued the letters the same day the US Senate’s Permanent Subcommittee on Investigations issued a report showing that public health officials under the Biden administration failed to warn the public of the myocarditis risk associated with Covid-19 vaccines and actively downplayed that risk.

The report compiled previously redacted information from government records recently obtained by subpoena and information gathered from earlier requests made by The Defender and other news organisations under the Freedom of Information Act (FOIA).

The records show how HHS officials under Biden avoided issuing a formal warning to the American public despite a safety signal that the Covid-19 vaccines could cause myocarditis and pericarditis, especially in young men.

For example, the report included internal emails showing that the CDC and FDA discussed issuing a Health Alert Network that would warn practitioners nationwide about the heart risks in May 2021, but ultimately decided against it.

It also showed that top health officials at HHS were warned that V-safe, another safety surveillance system, could miss “possible cases of cardiac adverse events” because it failed to include cardiac symptoms in its pre-programmed list of vaccine side effects for individuals to check off.

Yet, officials chose not to update the programme to include those events. Senators discussed the report and heard expert testimony in a contentious hearing on Wednesday.

Lawmakers and invited witnesses – including Dr Peter McCullough, Dr Joel Wallskog and attorney Aaron Siri – shared heated exchanges around a wide range of topics related to Covid-19 and beyond, including what “the science” shows, whether federal health officially intentionally concealed Covid-19 vaccine adverse events data, how the vaccine-injured have been ignored and abandoned, why lockdowns harmed children and the potential impact of recent funding cuts to federal health agencies..

Also this week, the FDA unveiled plans to limit approvals for updated Covid-19 vaccines to people over age 65 and people with one or more health conditions that put them at high risk for the virus, and require new clinical trials for the vaccines for children and teens. Experts continue to debate the implications of this shift.

The FDA’s vaccine advisory committee is also meeting today to decide on the composition of the fall Covid-19 shots.

• A Tell Media report / By Brenda Baletti – a senior reporter for The Defender