As recently as last week, many public health experts fiercely 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 changed all that.
Scientists are not yet sure whether the virus is easier to spread or less vulnerable to the body’s immune response. But with dozens of new mutations, the variant appears likely to elude vaccine protection to some extent.
Booster shots clearly increase antibody levels, strengthening the body’s defenses against infection, and may help offset any benefits Omicron has gained over the course of life.
Many experts who used to oppose boosters now believe that shots may offer the best defense against the new variant. The extra doses can slow the spread, at least, allowing vaccine manufacturers to develop a formulation specific to Omicron, if needed.
“Based on what we know about the potential for immune evasion, I would lean towards the administration of the booster,” said Dr CÃ©line Gounder, an infectious disease specialist at Bellevue hospital who was opposed. to reminders for all of the Biden administration. to push.
The administration does not wait for scientific consensus. Alarmed by preliminary reports on Omicron, officials from the Centers for Disease Control and Prevention said Monday that all American adults should receive booster shots.
The first confirmed Omicron infection in the United States was reported in San Francisco on Wednesday in a traveler who returned from South Africa to California on November 22. The individual had been fully vaccinated – but had not received a booster – and was exhibiting mild symptoms which were said to be improving.
The Omicron variant, first identified in southern Africa, has been discovered in at least 20 countries, and the World Health Organization has warned that the risk posed by the virus is “very high”. After news of the variant’s spread in South Africa, countries around the world reduced air travel to and from southern Africa.
Omicron carries more than 50 genetic mutations, including more than 30 on the tip of the virus, a protein on its surface. Vaccines train the body’s immune defenses to target and attack these spikes.
Until now, experts like Dr Gounder had argued that even though the potency of vaccines against Delta variant infection appeared to be waning, they still protected most people from serious illness, hospitalization and death. Booster doses should only be recommended for adults over 65 and those in long-term care facilities or who have weakened immune systems, they said.
If Delta were the only threat, boosters still wouldn’t be justified, said Dr Gounder and other researchers. But Omicron can be a more formidable foe.
“If it’s very resistant to antibodies, which seems likely but unproven, then additional doses are appropriate,” said John Moore, a virologist at Weill Cornell Medicine in New York City.
âI would love to see more data, but it won’t hurt anyone to have extra protection. “
Even before Omicron arrived, some experts were turning to boosters for all adults, as cases in the United States have increased again in recent weeks.
âIt impacts things like elective procedures at several hospitals in Massachusetts and elsewhere,â said Dr. Camille Kotton, infectious disease physician at Massachusetts General Hospital and CDC advisor. “We really need to end this.”
“Now, more than ever, is the perfect time to get vaccinated for people who have not yet been vaccinated, or to go for boosters,” she said.
Dr. Kotton’s initial reluctance was partly rooted in a lack of research regarding the safety of booster injections in young adults. Given some rare heart problems in young men after receiving the second dose of an mRNA vaccine, it was not clear whether the benefits outweigh the risks.
But the data now available has allayed her concerns, she said – so much so that she urged her college-aged sons to receive booster doses.
âOh yeah, I changed,â she said. âWith the risks and benefits in mind, it’s a great idea to get booster doses for those who qualify. “
More support for boosters among scientists could eventually complicate efforts to provide limited supplies of coronavirus vaccines to poor countries. The World Health Organization said for months, long before Omicron emerged, that the clamor for extra doses in rich countries was depriving poorer nations of the first doses they desperately needed.
Despite the WHO designation of Omicron as a high risk, the organization has not changed its stance on boosters.
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“At this time, there is no evidence to my knowledge that suggests that strengthening the entire population is necessarily going to provide greater protection to otherwise healthy people from hospitalization or dead, “Dr Mike Ryan, director of WHO, said Wednesday at a press conference.
He and other scientists have said the uncontrolled spread of the coronavirus through largely unvaccinated populations, like those in Africa, is likely to give rise to variants like Omicron.
Not all experts are lining up to support the booster shots.
The push for extra doses is based on the idea that antibodies are the central aspect of immunity, a false perspective that overlooks the importance of other parts of the immune system in preventing serious illness and death said Dr Paul Offit, vaccine director. Education Center at the Children’s Hospital of Philadelphia and an advisor to the Food and Drug Administration.
He said he would be more worried if vaccinated people infected with the Omicron variant were hospitalized en masse. But limited evidence to date suggests vaccines still prevent serious illness, he said.
âIt’s always been true – it’s been true for the first three variations, and it’s probably true here,â he said. âIf you make it a goal to protect yourself from minor illnesses, we will increase until the day we die. “
Even if Omicron is found to be vaccine resistant, one more injection of the original vaccines may not be the best solution, said Dr Offit: âI just think it’s a detour from what’s really going on. be the way to gain the upper hand. of this pandemic, which consists of vaccinating the unvaccinated.
But waiting may not be an option.
If lab tests indicate Omicron is avoiding vaccines, manufacturers say they’re ready to adapt new versions. This process will take at least a few months, and booster shots of current vaccines may be needed to help keep the variant under control until then.
Even though the antibodies stimulated by these injections are not as effective in repelling Omicron as against previous variants, the increase in the amount alone could compensate, Dr Gounder said.
âYou can replace some of that lower affinity by having the higher numbers,â she said.
If needed, multiple booster doses – first with current vaccines, then with Omicron-specific versions – should be carefully timed, as boosting immunity too frequently can backfire, Dr Moore said. Some immune cells may stop responding to vaccines.
âThis is where it all gets complicated – certainly, no one should be sitting on dogma here,â he said. âWe are reacting in a low-information environment where the consequences are potentially quite serious. “