WASHINGTON — A federal health advisory panel wrestled Friday with whether to widely authorize a booster dose of Pfizer’s two-shot COVID-19 vaccine for most Americans, ultimately recommending that a third dose be offered only to older or higher-risk individuals.
The Biden administration had hoped that states could begin rolling out a wide national booster shot campaign as soon as Monday, and the Food and Drug Administration advisory committee’s decision threw up a roadblock for that goal.
Medical experts on the FDA panel debated the question for hours and expressed skepticism about whether the available data on effectiveness and safety warrant urging every vaccinated American to get another shot.
All but two of the panel’s 18 voting members rejected Pfizer’s request that the company be allowed to offer extra doses to anyone 16 and older, six months after their second dose.
The revised recommendation instead calls on the FDA to allow booster shots for those 65 and older, or at high risk of a severe COVID-19 infection.
The panel’s recommendation is non-binding, but typically followed by top agency officials.
Still, questions remain to be answered, including what happens next for Americans who got shots produced by the other authorized COVID-19 manufacturers, Moderna and Johnson & Johnson.
Interpreting who exactly is at high risk of severe COVID-19 — such as health care or other front-line workers — will be up to an advisory panel for the Centers for Disease Control and Prevention, which is set to meet Wednesday and Thursday.
That panel’s recommendation will come after the Sept. 20 date that the Biden administration targeted for a national booster shot campaign.
President Joe Biden and his pandemic advisers announced the administration plan for boosters in mid-August, leapfrogging the federal regulatory panels as the administration sought to tamp down another rise in infections and hospitalizations.
Administration officials said the booster plan was announced early to give states time to prepare for another round of shots. But the public announcement appeared to irritate FDA officials involved in the approval process.
Two of the agency’s top vaccine scientists have said they will retire this fall — with the booster process a contributing factor in that decision, according to multiple news reports.
As federal health officials have scrambled to assess data on whether booster shots are needed, the country has been facing a fourth wave of cases, with an average of 145,000 infections and 1,300 deaths per day.
The overwhelming majority of current COVID-19 cases, hospitalizations and deaths are among people who have not received a vaccine against the disease.
But a series of studies have suggested that while the protection offered by the three COVID-19 vaccines has remained strong against severe infections, that protection has waned when it comes to asymptomatic or mild infections.
Federal health officials already approved a third COVID-19 shot last month for some immunocompromised individuals, who may not have received strong protection from the initial doses of the vaccine.
Officials with Pfizer presented their own data Friday in arguing that a third dose also will provide a significant improvement in protection for the broader population.
Dr. Sara Oliver, with the CDC’s National Center for Immunization and Respiratory Diseases, told the panel that it is difficult to assess from the available data whether the waning efficacy is due to the time elapsed since vaccination, or the intense level of contagiousness from the delta variant.
Several panel members expressed frustration with the limited data available.
Dr. Paul Offitt, director of the Vaccine Education Center at Children’s Hospital of Philadelphia, said there was too little information on the value of a third dose for younger individuals, who have been at a slightly higher risk of myocarditis, an inflammation of the heart.
Offitt said the data does suggest a booster could reduce asymptomatic or mild infections, but questioned how much that reduction could shift infection rates.
“The question becomes, what will be the impact of that on the arch of the pandemic? Which may not be all that much,” Offitt said. “Certainly we all agree that if we really want to impact this pandemic, that means to vaccinate the unvaccinated.”
Several on the panel, including Dr. Steven Pergam, with the Seattle Cancer Care Alliance, urged the need for including health care workers in the booster doses.
He also argued that reducing even mild infections could lift some strain on deeply overburdened health care systems.
“Do we want to wait until more previously vaccinated people get sick before we prevent them from getting sick?” asked Dr. Jay Portnoy, an allergist at Children’s Mercy Hospital in Kansas City, Mo., who serves on the FDA advisory panel—and said he plans to get his third dose as soon as possible.