A healthcare worker administers a dose of the Pfizer-BioNTech Covid-19 vaccine at a vaccination clinic in the Peabody Institute Library in Peabody, Massachusetts, U.S., on Wednesday, January 26, 2022.
Vanessa Leroy | Bloomberg | beautiful pictures
The new Covid omicron boosters may not be very effective at preventing Covid infections and mild illness, experts say, but they will likely help the elderly and other vulnerable groups stay out of hospital during this time. this winter.
Centers for Disease Control and Prevention, in a real-world study published this weekfound boosters to be 50% less effective for mild disease in most adult age groups when compared with unvaccinated individuals.
For the elderly, the booster dose was 19% effective in preventing mild illness when the fourth dose was given, compared with those who were not vaccinated. It was 23% effective for mild disease when the fifth dose was taken.
Although the vaccine’s effectiveness for mild illness is low, those who get the booster do better than those who don’t. Boosters increase people’s protection from mild illness by 28% to 56% compared with people who just had the old shot, depending on their age and when they got their last dose.
The Food and Drug Administration approved the booster shots at the end of August with the goal of restoring the high level of protection the vaccine demonstrated in late 2020 and early 2021. At that time, The injections are more than 90% effective against infections. But the first real data from the CDC indicates that the boosters don’t live up to those high expectations.
“The booster gives you some extra protection but it’s not that strong and you shouldn’t rely on it,” said John Moore, professor of microbiology and immunology at Weill Cornell Medical College. into it as the only defense against infection.”
Moore said people at higher risk from Covid have every reason to get a booster shot because it modestly increases protection. But he said common sense measures such as wearing masks and avoiding large crowds remain important tools for vulnerable groups because boosters are not highly effective at fighting infection.
The CDC study looked at more than 360,000 adults with healthy immune systems who were tested for Covid at retail pharmacies between September and November when omicron BA.5 prevailed. Participants received a booster shot, received two or more doses of the old vaccine, or they were not vaccinated. It then compares people who test positive for Covid with those who don’t.
The study did not evaluate how effective booster shots are for serious illness, so it’s not clear whether they offer better protection from hospitalization than older shots. The CDC in a statement said it will make data on more severe outcomes available when available.
Andrew Pekosz, a virologist at Johns Hopkins University, said the fact that the shots are providing some protection against infection in an age of highly immunogenic omicron sub-variants is a good indication that they will provide strong protection from hospitalization. Vaccines always work better for severe disease than for mild disease, he said.
“It’s better than nothing. Sure, it doesn’t show extremely high protection against infection,” Pekosz said. “I hope that then you’ll see even greater protection from hospitalization or death.”
Dr. Paul Offit, a member of the FDA’s vaccine advisory committee, said trying to prevent mild illness is not a viable public health strategy because the antibodies that stop the infection will wane. by the time.
“The protection against mild disease is no longer good in the age of the omicron sub-variant,” said Offit, an infectious disease specialist at Children’s Hospital of Philadelphia who helped develop the rotavirus vaccine. goal is to protect against serious illness”.
Dr Celine Gounder, a senior public health fellow at the Kaiser Family Foundation, said she is not worried about the data. Reducing risk even by a modest amount at the individual level can have a significant positive impact on public health at the population level.
“If you can reduce the risk in the elderly by 30 percent, maybe even 20 percent, it makes a lot of sense when 90 percent of COVID deaths occur in that group,” says Gounder. “For me, it’s really important that you keep that 65-year-old out of the hospital.”
The booster shots, called bivalent vaccines, target both omicron BA.5 and the original Covid strain that first appeared in Wuhan, China in 2019. The initial shots, called is a monovalent vaccine that covers only the first strain of Covid.
It is not yet clear how the enhancers will work against more immune-evasive omicron sub-variants, such as BQ.1 and BQ.1.1, which are currently dominant in the US Pfizer and Moderna last week says initial clinical trial data suggest that enhancers induce an immune response against these side variables.
About 11% of those eligible for the new booster, or 35 million people, have received the drug to date, according to CDC data. About 30% of seniors have been vaccinated.
