Scientists unsure boosters will prevent another wave
As winter looms and Americans increasingly gather indoors without masks or social distancing, a medley of new coronavirus variants is seeding a rise in cases and hospitalizations in counties across the nation.
The Biden administration’s plan for preventing a national surge depends heavily on persuading Americans to get updated booster shots of the Pfizer-BioNTech and Moderna vaccines. Now some scientists are raising doubts about this strategy.
Older adults, immunocompromised people and pregnant women should get the booster shots, because they offer extra protection against severe disease and death, said John Moore, a virus expert at Weill Cornell Medicine in New York.
But the picture is less clear for healthy Americans who are middle-aged and younger. They are rarely at risk of severe illness or death from COVID, and at this point most have built immunity through multiple vaccine doses, infections or both.
The newer variants, called BQ.1 and BQ.1.1, are spreading quickly, and boosters seem to do little to prevent infections with these viruses, as they are excellent evaders of immunity.
“If you’re at medical risk, you should get boosted, or if you’re at psychological risk and worrying yourself to death, go and get boosted,” Moore said. “But don’t believe that will give you some kind of amazing protection against infection, and then go out and party like there’s no tomorrow.”
The most recent boosters are “bivalent,” targeting both the original version of the coronavirus and the omicron variants circulating earlier this year, BA.4 and BA.5. Only about 12 percent of adults have opted for the latest shot.
In an interview, Dr. Peter Marks, the Food and Drug Administration’s top vaccine regulator, acknowledged the limitations of the available data on the updated boosters.
“It’s true, we’re not sure how well these vaccines will do yet against preventing symptomatic disease,” he said, particularly as the newer variants spread.
But, Marks added, “even modest improvements in vaccine response to the bivalent boosters could have important positive consequences on public health. Given the downside is pretty low here, I think the answer is we really advocate people going out and consider getting that booster.”
Diminishing returns from tinkering with the Pfizer-BioNTech and Moderna vaccines call for a new approach to protecting Americans altogether, Moore and other experts said. A universal vaccine that targets parts of the coronavirus that do not mutate would be ideal, for example. A nasal vaccine might be better at preventing infections than an injected one.
“Chasing variants by tweaking the mRNA vaccines is not a sustainable strategy,” Moore said. “There’s a need for better vaccine designs, but that needs a change of attitude at the government level.”
Recently, Pfizer-BioNTech and Moderna reported that their bivalent shots yielded antibody levels in study participants that were four to six times higher than those produced by the original vaccine.
But the companies were measuring antibodies against BA.4 and BA.5, not the rapidly accelerating BQ.1 and BQ.1.1 variants.
A spate of preliminary research suggests that the updated boosters, introduced in September, are only marginally better than the original vaccines at protecting against the newer variants — if at all.
The studies are small, based on laboratory tests, and have not yet been vetted for publication in a scientific journal. But results from several teams generally agree.
“It’s not likely that any of the vaccines or boosters, no matter how many you get, will provide substantial and sustained protection against acquisition of infection,” said Dr. Dan Barouch, head of Beth Israel Deaconess’ Center for Virology and Vaccine Research, who helped develop the Johnson & Johnson vaccine.
Designing a vaccine for an evolving virus is a formidable challenge. Pfizer, Moderna and federal regulators had to choose which coronavirus variants to target earlier this year, so enough vaccine could be manufactured by the fall.
But BA.4 has all but disappeared. BA.5 now accounts for less than 30 percent of cases and is swiftly receding. BQ.1, on the other hand, has sent numbers soaring in Europe.
That virus and its close relative, BQ.1.1, now account for 44 percent of U.S. coronavirus infections.
In recent research, Barouch’s team found that BQ.1.1 is roughly seven times as resistant to the body’s immune defenses as BA.5, and 175 times more so than the original coronavirus.
“It has the most striking immune escape, and it’s also growing the most rapidly,” he said.
BQ.1 is expected to behave similarly.