Covid-19 booster jabs will be limited to people over 65 or those at higher risk of serious illness, under new US government rules.
New placebo-controlled trials will be required to justify the booster vaccines for healthy individuals moving forward, a Food and Drug Administration (FDA) spokesman said.
In a letter to the New England Journal of Medicine, director of the FDA’s Centre for Biologics Evaluation and Research (CBER) Vinayak Prasad and Commissioner Martin Makary said the shift brought US policy more in line with Europe.
They described the initial rollout of Covid-19 vaccines as “a major scientific, medical, and regulatory accomplishment” – but said the benefits of repeated boosters in low-risk individuals remained uncertain.
They contrasted the US approach with that of countries such as the UK, France and Germany, which limit booster recommendations to the elderly and those with underlying conditions.
Benefit-risk balance
Going forward, the FDA said it believes it will continue to find the benefit-risk balance of continued boosters for people over 65, and people over the age of six months with one or more underlying conditions.
However, “for all healthy persons – those with no risk factors for severe Covid-19 – between the ages of six months and 64 years, the FDA anticipates the need for randomised, controlled trial data,” they said.
They identified adults aged 50 to 64 as an ideal study population, and said trials should assess whether boosters reduce symptomatic illness, severe disease, hospitalisation, and death.
The Centres for Disease Control and Prevention’s definition of risk factors is “vast, including obesity and even mental health conditions such as depression,” they wrote, adding that between 100 million and 200 million Americans would likely still qualify under this guidance.
Dr Prasad, a haematologist-oncologist who now leads the FDA’s Centre for Biologics Evaluation and Research (CBER), rose to prominence during the pandemic for publicly questioning the widespread use of boosters.