The US Department of Health and Human Services (HHS) has confirmed that the Food and Drug Administration (FDA) is investigating deaths that may be associated with COVID-19 vaccines across multiple age groups. The agency has not yet clarified which age groups are included in the expanded probe.

The announcement follows earlier comments from FDA Commissioner Marty Makary, who indicated that the agency was examining deaths in younger populations potentially linked to post-vaccination myocarditis, a rare form of heart inflammation.

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Internal memo cited possible paediatric cases

Last month, FDA Chief Medical and Scientific Officer Vinay Prasad told staff in an internal memo that COVID-19 vaccines had likely contributed to the deaths of at least 10 children who experienced heart inflammation following vaccination.

The statement was based on an initial review of 96 deaths reported between 2021 and 2024, though the analysis has not been published in a peer-reviewed journal. The memo did not detail the underlying medical conditions of the children, nor did it specify which vaccine manufacturers’ products were involved.

Myocarditis, although rare, has been previously observed in young males following mRNA vaccination.

Vaccine makers reaffirm safety

mRNA vaccine developers responded to the news by reiterating confidence in their products:

  • Moderna stated there were no new or undisclosed safety concerns regarding its Spikevax vaccine in children or pregnant women.
  • Pfizer and BioNTech, manufacturers of another widely used mRNA vaccine, similarly reaffirmed the safety and efficacy of their COVID-19 shot.

Both companies noted that myocarditis cases associated with vaccines remain extremely rare and typically resolve with treatment.

Shifts in US vaccine policy under new administration

The probe comes as US Health Secretary Robert F. Kennedy Jr. has instituted sweeping changes to national vaccination policy. Kennedy, a long-time vaccine sceptic, has limited access to COVID-19 vaccines to adults aged 65 and older and those with underlying health conditions.

Other major policy changes include:

  • Dropping the longstanding recommendation for the hepatitis B birth dose
  • Cutting federal funding for mRNA vaccine programmes
  • Publicly linking vaccines to autism — views that run counter to established scientific research and consensus

These policy shifts have sparked concern among public health experts, who warn that reduced vaccination rates may increase vulnerability to infectious diseases.

What happens next

The FDA’s ongoing investigation is expected to review medical records, autopsy findings, vaccine lot information and reporting trends from the US Vaccine Adverse Event Reporting System (VAERS). Regulators emphasise that identifying a temporal association does not imply causation, and that thorough analysis is required before drawing conclusions.

The HHS has said updates will be provided once the FDA completes its assessment.