Just last week, many public health experts strongly opposed the Biden administration’s campaign to roll out booster shots of the coronavirus vaccines to all American adults. There was little scientific evidence to support additional doses for most people, the researchers said.
The Omicron variant has changed all that.
Scientists are not yet sure whether the virus spreads more easily or whether it is less vulnerable to the body’s immune response. But with dozens of new mutations, the variant seems likely to evade vaccine protection to some degree.
Booster shots clearly increase antibody levels, boost the body’s defenses against infection, and can help negate the benefits Omicron has gained through evolution.
Many of the experts who opposed boosters now believe that the shots can provide the best defense against the new variant. The extra doses could slow the spread, at the very least buying time for vaccine makers to develop an Omicron-specific formulation, if needed.
“Based on what we know about the potential for immune evasion, I would make the mistake of giving the booster,” said Dr. Celine Gounder, an infectious disease specialist at Bellevue Hospital Center, who had resisted the Biden administration’s boosters-for-all push.
The administration does not wait for scientific consensus. Alarmed by the preliminary reports on Omicron, officials at the Centers for Disease Control and Prevention said Monday that all U.S. adults should be getting booster shots.
The first confirmed Omicron infection in the United States was reported Wednesday in San Francisco, in a traveler who returned to California from South Africa on Nov. 22. The person had been fully vaccinated – but had not received a booster – and showed mild symptoms that were said to be getting better.
The Omicron variant, which was first identified in southern Africa, has been discovered in at least 20 countries and the World Health Organization has warned that the risk of the virus is “very high”. Following news of the variant’s spread in South Africa, countries around the world have restricted air traffic to and from southern Africa.
Omicron carries more than 50 genetic mutations, more than 30 of which are at the peak of the virus, a protein on its surface. Vaccines train the body’s immune defenses to attack and attack these spikes.
Until now, experts such as Dr. Gounder argued that while the vaccines’ potency against infection with the Delta variant seemed to wane, they still protected most people from serious illness, hospitalization and death. Booster doses should only be recommended for adults over age 65 and people who stay in long-term care facilities or have weak immune systems, they said.
If Delta were the only threat, boosters still wouldn’t be warranted, according to Dr. Gounder and other researchers. But Omicron may be a more formidable foe.
“If it’s highly resistant to antibodies, which seems likely but hasn’t been proven, then additional doses are appropriate,” said John Moore, a virologist at Weill Cornell Medicine in New York.
“I’d love to see more data, but it wouldn’t hurt anyone to have extra protection.”
Even before the arrival of Omicron, some experts came along to give boosters to all adults as cases in the United States have risen again in recent weeks.
“It affects things like elective procedures at multiple hospitals in Massachusetts and elsewhere,” says Dr. Camille Kotton, Massachusetts General Hospital infectious disease physician and advisor to the CDC. “We really need to put an end to this.”
“Now, more than ever, is a good time to get vaccinated for people who have not yet been vaccinated, or to get boosters,” she said.
The initial hesitation of Dr. Kotton was partly rooted in a lack of research on the safety of booster shots in young adults. Given certain rare heart problems in young men after receiving the second dose of an mRNA vaccine, it was not clear that the benefits outweighed the risks.
But the data now available has allayed her concerns, she said — so much so that she has urged her college-age sons to get booster doses.
“Oh yes, I’ve changed,” she said. “When we think about risks and benefits, it’s a really good idea to get booster doses for people who qualify.”
Greater support for boosters among scientists could eventually complicate efforts to provide limited supplies of the coronavirus vaccines to poor countries. The World Health Organization has been saying for months, long before Omicron appeared, that calls for extra doses in rich countries robbed poorer countries of the first doses they desperately needed.
Despite the WHO’s designation of Omicron as high-risk, the organization has not changed its stance on boosters.
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“At this point, there is no evidence that I know of to indicate that boosting the entire population will necessarily provide better protection for otherwise healthy individuals from hospitalization or death,” Dr. Mike Ryan, a director at the WHO, said at a news conference on Wednesday.
He and other scientists have said the uncontrolled spread of the coronavirus through largely unvaccinated populations, such as those in Africa, will likely lead to variants such as Omicron.
Not all experts line up to support booster shots.
The push for extra doses is based on the idea that antibodies are the central aspect of immunity, a misguided perspective that overlooks the importance of other parts of the immune system in preventing serious illness and death, said Dr. Paul Offit, director of the Vaccine Education Center at the Children’s Hospital of Philadelphia and a consultant to the Food and Drug Administration.
He said he would be more concerned if vaccinated people infected with the Omicron variant were hospitalized en masse. But so far, there’s limited evidence to suggest the vaccines still prevent serious illness, he said.
“It’s always been that way — it was true for the first three variants, and it probably will be here too,” he said. “If you set the goal of protecting against mild disease, we’ll keep going until the day we die.”
Even if Omicron proves resistant to vaccines, an additional injection of the original vaccines may not be the best solution, said Dr. Offit: “I just think this is a roundabout way of what will really be the way to get to the top of this pandemic, which is to vaccinate the unvaccinated.”
But waiting may not be an option.
If lab tests show that Omicron is bypassing the vaccines, manufacturers say they’re ready to tailor new versions. That process will take at least a few months, and booster shots of current vaccines may be needed to keep the variant under control until then.
Even if the antibodies stimulated by those injections aren’t as effective at fighting off Omicron as they were against previous variants, the increase in the amount alone could compensate, said Dr. gounder.
“You’re able to negate some of that lower affinity by using the higher numbers,” she said.
If needed, multiple booster doses — first with current vaccines, then with Omicron-specific versions — should be timed at excellent timing, because boosting immunity too often can backfire, said Dr. Moore. Certain immune cells may stop responding to the vaccines.
“This is where it all gets complicated — sure, nobody should be sitting on dogma here,” he said. “We are responding in a low-information environment where the consequences could be quite severe.”
