Biden Plan Prods Scientists to Back Boosters Despite Murky Data
Signs of pressure are already starting to gather around a meeting of vaccine advisers to the Centers for Disease Control and Prevention that forms a key step in the Biden administration’s plan to give booster shots to most U.S. adults.
The discussion, originally scheduled to take place Tuesday, has been delayed to start Aug. 30 and last two days, according to a spokesperson. With the controversial plan slated to roll out third shots as soon as Sept. 20, the CDC’s Advisory Committee on Immunization Practices is under the gun.
The administration has already signaled that it doesn’t have all the scientific data on boosters that it would like, and that it’s responding out of caution. White House Covid adviser Anthony Fauci said earlier this week that it wasn’t clear whether booster shots would curb transmission of the virus among the vaccinated.
“This is what is really concerning to many of us,” said Celine Gounder, an infectious disease specialist at Bellevue Hospital in New York. “Because it feels like the scientific process is being short circuited by political concerns... It is almost science by popular demand.”
The Food and Drug Administration is working to give full approval to Pfizer Inc.’s vaccine as soon as early next week, according to a person familiar with the matter who asked not to be identified because the information isn’t public. The agency didn’t immediately respond to a request for comment late in the day.
But it’s uncertain whether or when the FDA will authorize the extra shots. The CDC’s ACIP meeting, a public discussion by doctors and academics from outside the government of the latest research -- some of which may not yet be published -- is likely to be a pivotal moment in the booster debate.
Whipped by the highly contagious delta strain, Covid cases are surging in this country to levels not seen in months. But the increases in hospitalizations and deaths are largely due to unvaccinated people -- not to those who have already had shots and would be eligible for boosters.
Two real-world studies published in CDC’s Morbidity and Mortality Weekly Report show that, in the U.S., vaccine protection against hospitalization is holding up well, with little to no decline seen. Other data published in the same journal shows some decline in vaccine effectiveness against preventing infections as delta took over, but involves many complex variables, making it hard to tell what’s driving the change.
A broad booster shot plan is undeniably appealing on the surface. They may help bolster individual protection a bit, especially against mild breakthrough infections. The administration has already begun offering third shots of mRNA vaccines to people with weakened immune systems, who don’t respond well to the initial two shots.
But whether rushing them to relatively healthy, vaccinated people is a good use of money and government resources is a far different matter. Boosters from Moderna Inc. and the partnership of Pfizer and BioNTech SE have been shown to raise bloodstream levels of coronavirus antibodies, but not to improve prevention. The administration says it’s still gathering data on Johnson & Johnson’s Covid shot, and will make a determination for recipients later.
While the U.S. has vaccinated just over half its population, the virus has been gaining in infectiousness. The two trends essentially cancel one another out, putting the country’s virus control efforts back to where they were in March 2020, according to Ellie Murray, a Boston University School of Public Health epidemiologist who said she has reviewed the data and is skeptical of the current need for boosters.
Without much higher vaccination rates, it’s unlikely the country can bring down transmission to a level where society can go back to normal. Giving boosters doesn’t change the calculus much.
“From a population level it, it doesn’t help us in controlling the pandemic,” she said. “The math doesn’t work.”
Meanwhile, rushing out a booster plan could set up the country for an endless treadmill of one after another -- a potentially futile effort that will prevent mild cases rather than eradicate the virus. The increased infectiousness of the delta variant means that far higher national vaccination rates are now needed to return society to normal, Murray said.
Giving boosters in states where vaccination rates are high will make no difference in the more hesitant states, said Amesh Adalja, an infectious disease doctor at the Johns Hopkins Center for Health Security. The focus should lowering hospitalizations, which vaccines still do quite well, not in preventing every last mild breakthrough case, he said.
“If we give everybody third doses now,” he said, “Mississippi will still be hellish.”
Then there is the question of what is really behind the waning efficacy seen in some studies: Several other factors besides declining immunity over time may be driving the change. For example, the delta variant itself may reduce vaccine protection against mild disease, as it multiplies in the nose much faster, even as protection remains strong against severe disease.
Changes in public behavior and the opening of society may have exposed more people to higher doses of virus. And some people who got vaccinated early on, such as health-care workers, may be more likely to have heavier viral exposures through their jobs, further muddling comparisons.
“My worry is that all a booster might do is just prevent asymptomatic or mild symptomatic breakthrough cases in people whose immune systems would get the disease under control in a few days anyway,” said Jeffrey Morris, a biostatistician at the University of Pennsylvania’s Perelman School of Medicine, “thus not affecting health outcomes in a meaningful way.”
One of the studies the CDC published, an analysis of real-world data from New York, showed vaccine efficacy against infections declining from 92% to 80% from the beginning of May to the end of July as delta took over. But by far the biggest decline occurred in 18- to 49-year-olds, not elderly people who public health authorities are most worried about.
That raises the possibility that it was really changes in behavior, like more nights in restaurants and at ballgames, that drove the decline, not an waning of vaccine-induced protection, said David Dowdy, an epidemiologist at Johns Hopkins Bloomberg School of Public Health.
Booster shots for nursing home residents and the very elderly may make sense, Gounder said, but the data supporting a broad rollout is “very thin.”
“There is a bit of looking into a crystal ball and jumping to conclusions that we just don’t have the data for yet,” she said.
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