An FDA panel voted against recommending Pfizer-BioNTech booster shots for people 16 years of age and older.

The independent panel believes that two doses of the Pfizer vaccine can still safeguard Americans against the transmission of the very contagious COVID-19 Delta variant, and doesn’t think that a booster shot is necessary right now, The New York Times reports.

The panel was comprised of a number of experts, like infectious disease doctors and statisticians who questioned the need of another shot of the vaccine if the current two doses have protected Americans against serious illness and hospitalization. 

“It’s unclear that everyone needs to be boosted, other than a subset of the population that clearly would be at high risk for serious disease,” Dr. Michael G. Kurilla, a committee member and official at the National Institutes of Health, told the publication.

Some experts on the panel also said more data is needed before they can make a decision regarding booster shots. “In particular, there is a lack of data on effectiveness and duration,” Dr. Michael Carome, director of Public Citizen’s Health Research Group, told the New York Post. “Current evidence does not appear to show a need for boosting.”

The advisers did agree that people who are 65 years and older and/or at high risk of severe illness should receive a booster shot of Pfizer, six months after being fully vaccinated.

This has put a damper on Joe Biden’s plans. The president was hoping to approve a third shot of the vaccine, so that adults—who had already gotten their two doses of Pfizer or Moderna at least eight months ago—could begin getting their booster shots the week of Sept. 20.

While the FDA is not obligated to heed the independent advisory panel’s advice, it has followed its direction on COVID-19 vaccinations thus far.