Covid Vaccine Policy on Boosters and New Trials
In what is seen as a major shift in its Covid-19 vaccine strategy, FDA is announcing a more targeted regulatory framework for annual booster shots that focuses on protection for high-risk individuals and calling for new clinical trials to evaluate the vaccines’ benefits in healthy Americans. Since the pandemic, Covid-19 vaccine boosters have been recommended for all Americans over the age of six months, while less aggressive immunization policies have been implemented in other developed nations. A course change is now being charted in a 5/20 New England Journal of Medicine online commentary penned by FDA commissioner Marty Makary and CBER director Vinay Prasad due to what they say is declining public trust, poor booster uptake, and growing skepticism.
According to them, fewer than 25% of Americans received Covid-19 boosters in each of the past two seasons. Uptake among children under 12 dropped below 10% in the 2024–2025 season, and even among adults over 75, only about half received a booster. Hesitancy has extended to health care workers as well, with less than one-third participating in the 2023–2024 campaign. To make matters worse, they say this downturn has raised broader public health concerns and may be affecting other immunizations, including the measles–mumps–rubella vaccine.
Going forward, the officials say FDA will limit its current broad Covid vaccine approvals to two main groups — adults over 65 and people over six months old who are at high risk for severe disease, as defined by the CDC. This includes those with conditions such as obesity, diabetes, or even mental health disorders like depression. These groups, which could total around 200 million Americans, will continue to have access to updated vaccines based on their the ability to generate antibody responses (immunogenicity).
However, for healthy individuals aged six months to 64 years, the agency is raising the bar, requiring randomized, controlled trials that demonstrate meaningful clinical benefits — such as reduced symptomatic infection, hospitalizations, or deaths. “We simply don’t know whether a healthy 52-year-old who’s had Covid three times and six previous vaccine doses will benefit from a seventh,” the officials write. “We need gold-standard data.”
To fill this evidence void, the officials say vaccine makers will be encouraged to conduct robust trials in healthy populations — especially among people aged 50 to 64, where global expert opinion remains divided. The preferred trial design includes using placebo controls, including participants with prior infections, and tracking outcomes like symptomatic Covid-19 over at least six months. The trials should aim to show at least a 30% reduction in symptomatic disease, they say.
“Insofar as possible, when approving a Covid-19 vaccine for high-risk groups, the FDA will encourage manufacturers to conduct randomized, controlled trials in the population of healthy adults as part of their postmarketing commitment,” the officials say.