FDA experts are still puzzled over who should get which covid shots and when

Reviewed by Emily Henderson, B.Sc.Jan 27 2023

At a meeting to simplify the nation's covid vaccination policy, the FDA's panel of experts could agree on only one thing: Information is woefully lacking about how often different groups of Americans need to be vaccinated. That data gap has contributed to widespread skepticism, undervaccination, and ultimately unnecessary deaths from covid-19.

The committee voted unanimously Thursday to support the FDA's proposal for all vaccine-makers to adopt the same strain of the virus when making changes in their vaccines, and suggested they might meet in May or June to select a strain for the vaccines that would be rolled out this fall.

However, the panel members disagreed with the FDA's proposal that everyone get at least one shot a year, saying more information was needed to make such a declaration. Several panelists noted that in recent studies, only about a third of people hospitalized with a positive covid test actually were there because of covid illness. That's because everyone entering a hospital is tested for covid, so deaths of patients with incidental infections are counted as covid deaths even when it isn't the cause.

The experts questioned the rationale for annual shots for everyone, given that current vaccines do not seem to protect against infection for more than a few months. Yet even a single booster seems to prevent death and hospitalization in most people, except for the very old and people with certain medical conditions.

"We need the CDC to tell us exactly who is getting hospitalized and dying of this virus — the ages, vulnerability, the type of immune compromise, and whether they were treated with antivirals. And we need immunological data to indicate who's at risk," said Dr. Paul Offit, director of the Vaccine Education Center and a pediatrician at Children's Hospital of Philadelphia. "Only then can we decide who gets vaccinated with what and when."

Offit and others have expressed frustration over the lack of clear government messaging on what the public can expect from covid vaccines. While regular boosters might be important for keeping the elderly and medically frail out of the hospital, he said, the annual boosters suggested by the FDA and the drug companies may not be necessary for everyone.

"The goal is to keep people out of the hospital," he said. "For the vulnerable, it would be important for vaccines to keep up with circulating strains. But for the general population, we already have a vaccine that prevents hospitalization."

Other panelists said the government needs to push research harder to get better vaccines. Pamela McGinnis, a retired official of the National Institutes of Health, said she had trouble explaining to her two young-adult sons why they promptly got sick after venturing out to bars one night only weeks after getting their bivalent booster.

"'Think how sick you would have gotten if you weren't fully vaccinated' is not a great message," she said. "I'm not sure 'You would have landed in the hospital' resonates with recipients of the disease."

Members of the FDA's advisory committee have been irked in recent months, saying the agency didn't present them with all the data it had on the bivalent vaccine before it was released in September. And some critics have said the FDA should have instructed drug companies to include only the newer strains of the virus in the shot.

Asked about that Thursday, Jerry Weir, a senior FDA vaccine officer, said his "gut feeling" was that a vaccine matched to a single omicron strain would have performed better than the bivalent shot, which also contains the original covid strain. "But the real question is where we're headed," he said, "and I don't know the answer."

Perhaps the most important presentation Thursday was from Heather Scobie, who keeps tabs on covid at the Centers for Disease Control and Prevention. She reported that fewer than half of Americans 65 and older had gotten the latest booster, and that only two-thirds of that age group had gotten even a single booster.

Yet evidence continues to mount that it's mostly the elderly who are at serious risk from covid. Death rates from the disease have declined in every age group except those over 75 since April, despite the uptick in new strains. Except for the very old, the death rate has hovered around 1 in 100,000 since April. Earlier in 2022, babies 6 months old and younger were hospitalized and died at relatively high rates. Vaccination levels in the 4-and-under group hover at about 10%.

While acknowledging the FDA's desire to regularize its covid vaccine policy, panel members said it's still too early to know for sure whether covid will surge only in the winter, like flu, respiratory syncytial virus, and other respiratory infections.

"For the next few years we may not know how often we need to make a strain change in the vaccine," said Dr. Steven Pergam, medical director of infection prevention at the Seattle Cancer Care Alliance. Or even if people who are not in poor health or elderly need additional boosters.

One vaccine-maker represented at the meeting, Novavax, said it would need to know by the end of March which strain to include in its vaccine for fall. Companies with mRNA vaccines like Pfizer and Moderna can change their formulas faster, but their products aren't clearly better than Novavax's.

All three of those vaccine-makers revealed at the meeting that they are developing single-dose vials or prefilled syringes. Up to now, they've delivered their vaccines in multidose vials, but since the government has run out of money to buy vaccines, individual pediatricians may order them in the future. Since the vaccine must be used quickly once a vial is open, doctors are leery of wasting vaccine and losing money.