As winter approaches and Americans increasingly congregate indoors without masks or social distancing, a mix of new coronavirus variants is driving increased cases and hospitalizations in counties across the country.
The Biden administration’s plan to prevent a nationwide surge hinges heavily on persuading Americans to get updated booster shots of the Pfizer-BioNTech and Moderna vaccines. Now, some scientists are casting doubt on this strategy.
The elderly, immunocompromised people and pregnant women should get the booster shots because they provide extra protection against serious illness and death, said John Moore, a virologist at Weill Cornell Medicine in New York.
But the picture is less clear for healthy middle-aged and younger Americans. They are rarely at risk of serious illness or death from Covid, and by this point most have developed immunity through multiple doses of the vaccine, infections or both.
The newer variants, called BQ.1 and BQ.1.1, spread quickly, and boosters seem to do little to prevent infections with these viruses, as they are excellent immunity escapees.
“If you’re at medical risk, you should be boosted, or if you’re at psychological risk and you’re worried to death, go get boosted,” Dr Moore said. “But don’t think it’s going to give you some kind of incredible protection against infection, 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% of adults opted for the latest vaccine.
In an interview, Dr. Peter Marks, the Food and Drug Administration’s lead vaccine regulator, acknowledged the limitations of the data available on the updated recalls.
“It’s true, we don’t yet know how well these vaccines will prevent symptomatic disease,” he said, especially as newer variants spread.
But, Dr. Marks added, “Even modest improvements in vaccine response to bivalent boosters could have significant positive public health consequences. Since the downside is pretty low here, I think the answer is that we’re really advocating for people to go out and consider getting this booster.
Learn more about the coronavirus pandemic
- Changing attitudes: Most offices, restaurants and schools are back to business as usual, but the coronavirus has not gone away.
- Long Covid: People who took the antiviral drug Paxlovid days after being infected with the coronavirus were less likely to suffer long months of Covid later, a study has found.
- Updated boosters: New findings show that the updated boosters from Pfizer and Moderna are better than their predecessors at boosting antibody levels against the most common version of the virus currently circulating.
- Personality changes: New research suggests that Covid’s disruption of social rituals and rites of passage has made people less outgoing, creative, agreeable and conscientious.
Diminishing returns from tinkering with Pfizer-BioNTech and Moderna vaccines call for a new approach to protect Americans as a whole, Dr. 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 may be more effective at preventing infections than an injected vaccine.
“Variant hunting by modifying mRNA vaccines is not a sustainable strategy,” Dr Moore said. “There is a need for better vaccine designs, but that requires a change in attitude at government level.”
Recently, Pfizer-BioNTech and Moderna reported that their bivalent vaccines produced 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 fast-accelerating BQ.1 and BQ.1.1 variants. A flurry of preliminary research suggests the updated boosters, introduced in September, are only marginally better than the original vaccines at protecting against new variants — if at all.
The studies are small, based on laboratory tests, and have not yet been approved for publication in a scientific journal. But the results of several teams generally agree.
“Any vaccine or booster, no matter how many you receive, is unlikely to provide substantial and lasting protection against infection,” said Dr. Dan Barouch, director of the Beth Israel Deaconess’ Center for Virology and Vaccine Research, which helped develop the J.&J. vaccine.
Designing a vaccine against an evolving virus is a formidable challenge. Pfizer, Moderna and federal regulators had to choose which coronavirus variants to target earlier this year, so that enough vaccines could be made by fall.
But BA.4 has practically disappeared. BA.5 now accounts for less than 30% of cases and is falling rapidly. BQ.1, on the other hand, sent skyrocketing numbers in Europe. This virus and its close relative, BQ.1.1, now account for 44% of coronavirus infections in the United States.
In recent research, Dr. Barouch’s team found that BQ.1.1 is about seven times more resistant to the body’s immune defenses than BA.5, and 175 times more so than the original coronavirus. “It has the most striking immune evasion, and it also grows the fastest,” he said. BQ.1 should behave similarly.
Right now, most Americans have some degree of immunity to the coronavirus, and it’s no surprise to scientists that the variant that best evades the body’s immune response is likely to out-compete its rivals.
The new bivalent booster boosts antibody levels, as any booster should.
But the fact that the dose is bivalent may not mean much. In August, a modeling study by immunologists in Australia suggested that any booster would confer additional protection, but that a variant-specific vaccine was unlikely to be more effective than the original vaccine.
“The bulk of the benefit comes from providing a booster dose, whether it’s a monovalent or bivalent vaccine,” the World Health Organization warned last month.
Studies have shown that most antibodies produced by a vaccine targeting BA.5, for example, still only recognize the original virus.
This is because of a phenomenon called “immune fingerprinting”, in which the body preferentially repeats its immune response to the first variant it encountered, although it is alerted to a newer variant. Most of the antibodies people make after receiving the bivalent vaccine only recognize the original coronavirus.
“It’s easier for the immune system to revert to something it’s seen before,” said Florian Krammer, an immunologist at the Icahn School of Medicine at Mount Sinai in New York. (Dr. Krammer has been a consultant for Pfizer.)
He and other experts have suggested that booster shots should have been “monovalent”, simply targeting recent variants. Instead, the makers effectively cut the new booster’s crucial Omicron-specific component in half, undermining the effectiveness of the shot, they said.
Still, Dr. Krammer was more optimistic about boosters in general, despite recent research. The new studies looked at the immune response soon after vaccination, and the response may improve over time, he said.
“We’ll see later with larger studies and studies if there’s a good or significant benefit, but I think it’s definitely not worse,” he added. “I don’t see a lot of risk when you get the vaccine, so might as well benefit.”
There may be ways around the immune footprint – perhaps with a second dose of a bivalent vaccine that builds on the immune response after the first, just as the second dose of the initial vaccine series cemented protection.
“What we need to do now to get through the next few months as I think we’re in for another wave of incipient wave of Covid,” Dr Marks said. “And then we have to look ahead and look at how we’re going to do things differently in the future.”
The FDA has allowed boosters to be used at least two months after a previous dose or infection. But raising so early can backfire, according to some studies. Extending the interval between boosters to five or six months may be more effective, giving the immune system more time to fine-tune its response.
Regardless of when, adding another shot to the regimen seems unlikely to motivate Americans to opt for vaccination.
“Each new booster we deploy will have lower and lower absorption, and we’re already pretty close to the bottom,” said Gretchen Chapman, a health behavior expert at Carnegie Mellon University in Pittsburgh.
The Biden administration may have no choice but to promote recalls given the lifting of other precautions, Dr. Chapman said. But most people make decisions based on what others in their social network are doing or what their political and community leaders recommend, not esoteric scientific data, she noted.
“We shouldn’t spend a lot of political capital trying to get people to get this bivalent recall because the benefits are limited,” she added. “It’s more important to get people who have never had the first round vaccinated than to get people like me to get their fifth shot.”
The Biden administration might have a better chance of persuading people to get boosters if other vaccines, such as Novavax or J.&J., were available for that purpose, she added. This may be especially true for people who have been hesitant to get vaccinated because they had a strong reaction to an mRNA vaccine.
Even from a scientific perspective, it may make more sense to diversify the body’s antibody response with different vaccines than to keep rolling out versions of mRNA vaccines, some experts have said.
Dr. Marks said the FDA may recommend Novavax as a second booster after reviewing the data. Until then, this vaccine is only authorized as a first booster for people who are unwilling or unable to receive an mRNA vaccine.
This rule “is completely ridiculous,” said Dr. Moore. “If the FDA’s goal is to increase vaccine uptake and boost the immunity of the American population, why are they imposing restrictions like this?”
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