U.S. FDA vaccine advisers face thorny question: Are COVID-19 boosters needed?

The White House’s move usurped the normal process by which the Food and Drug Administration and the U.S. Centers for Disease Control and Prevention make these kind of science-based decisions, according to interviews with six current and former FDA scientists and members of the Centers for Disease Control and Prevention’s advisory committee.

On Wednesday, the FDA scheduled a meeting to consider a third booster dose of the Pfizer Inc-BioNTech SE vaccine and may discuss others. Moderna has submitted data to the FDA for consideration of its booster, and Johnson & Johnson said last week it was in discussions with the agency about one.

“The recommendation shouldn’t precede the data, which is what happened here. That’s why people are so upset,” said a source close to the FDA advisory committee who was not authorized to speak officially.

These experts took the FDA’s decision to hold a panel advisory meeting on boosters as a promising sign that their opinions would be taken into account, but said a positive outcome was not guaranteed.

Jesse Goodman, an infectious disease expert at Georgetown University in Washington and former chief scientist for the Food and Drug Administration, said the agency would need to review all relevant data before Sept. 17 to be ready for the committee meeting.

“We need to see that there is a meaningful increase in antibody levels and there are no red flags,” he said.

Norman Baylor, CEO of Biologics Consulting and former director of the FDA’s Office of Vaccine Research and Review, said this will be a challenge because scientists still do not agree on the level of antibodies in the blood that predicts vaccine protection.

Much of the drug company’s argument in favor of boosters hinges on data showing that antibodies diminish over time and that another shot increases them.

“One of the things that the committee members have to face is… what does this mean?” Baylor said. “You see an increase, but is this increase enough? And for how long?”

Who should get a booster dose?

An intense debate is to be expected about whether most Americans should get another dose rather than just those at risk of serious illness, such as the elderly and those with weakened immune systems.

“The data has to show — show me you’re solving an important public health problem,” said Dr. Greg Poland, a former member of the FDA Vaccine Advisory Committee and chair of the Mayo Clinic Vaccine Research Group.

The problem, according to Poland and others, is that the current crop of vaccines is designed to prevent hospitalization and death, which is what the CDC says they continue to do.

The Biden administration has received a signal from Israel, where early data shows that a booster campaign appears to reduce transmission of the malignant delta variant, which has begun to cause mostly mild and asymptomatic infections in fully vaccinated people.

Boosters increase levels of antibodies that fight infections. But it is immune memory from other components of the immune system that provides protection from severe illness and hospitalization, and this can last for years.

“No matter how many booster doses you give, you can’t convert a disease-reducing vaccine into a vaccine that prevents infection,” Poland said.

Whatever the US decides on is likely to influence decisions about boosters in other parts of the world, said Dr. Amesh Adalja, an infectious disease expert at the Johns Hopkins Center for Health Security.

“I think you’ll probably see a trend in high-income countries to increase subsidies if the FDA gives them,” he said.