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Lauran Neergaard
U.S. health officials are critical about providing Faced with a decision. This fall, the new COVID-19 booster shots have been modified to better match recent changes in the shape-changing coronavirus.
Moderna and Pfizer tested updated shots against the hyperinfectious Omicron variant. The Food and Drug Administration adviser will discuss whether it is time to switch on Tuesday. Similar moves by other countries.
"This is the most difficult science," FDA Vaccine Director Dr. Peter Markes told The Associated Press that a final decision is expected within a few days of the advisory board's recommendations. I added.
The current COVID-19 vaccine has saved millions of lives worldwide in just one year of use. And the shots of Moderna and Pfizer provide the worst results, especially after booster administration, that is, strong protection against severe illness and death.
However, these vaccines target the original coronavirus strain, and their defense against infection is significantly reduced between weakened immunity and constant barrage of mutants. The challenge is to determine if a fine-tuned booster is likely to blunt another surge if there is no way to predict which mutant will be the main threat.
In an analysis prepared for Tuesday's meeting, FDA officials said last winter's version of Omicron had already been replaced by its more contagious relatives. I admitted that it was "slightly outdated".
"We obviously want to get it right enough," Marks said, so in another shot, "we get full-season protection."
Many experts say that updated boosters promise at least a little more profit.
Harvard T.H. epidemiologist William Hanage says it is "more likely to be useful" than simply adding today's vaccine. Chan School of Public Health.
This assumes that the virus will not throw another curve ball.
"We couldn't come up with a better antimutation vaccine because we're following rather than moving on to the very annoyances," said the Scripps Research Translational Institute. Dr. Eric Topol said. He urged major governments to promote the next generation of immunization.
In addition to concerns about the wave of COVID-19 in winter, about half of Americans subject to that very important first booster dose never receive it. It means that. The updated version may seduce some of them.
But "we need to change expectations," said Dr. William Moss of the Johns Hopkins Bloomberg School of Public Health. "Our strategy does not allow booster immunization every few months or even every six months to prevent infection."
The leading candidate is a scientist saying " This is what we call a "divalent" shot. This is a combination of the original vaccine and Omicron protection.
This promotes the production of antibodies that fight at least some viruses that are strong enough for the original vaccine to cross-reactive with new variants, in addition to the proven benefits for severe diseases. To do so, said E. John, an immunologist at the University of Pennsylvania, Wellie.
"It's very important to be able to push the boost response a bit in one or the other direction without losing the core," he said.
Moderna and Pfizer's combo shots significantly increase the level of antibodies that fight Omicron in adults who have already been vaccinated three times, not just three routine doses. I found that.
Recipients have also developed antibodies that can fight the latest relatives of Omicron named BA.4 and BA.5, but not many. It is not clear how much protection will be converted for how long.
Antibodies are an important first layer of defense formed after vaccination or prior infection. By recognizing the outer coating (peplomer) of the coronavirus and blocking its invasion into cells, infection can be prevented.
However, the antibodies spontaneously decline and each new variant comes with a different-looking peplomer, so it is likely that detection by the remaining antibodies can be avoided. Become. According to another study published this month in Nature and the New England Journal of Medicine, the latest Omicron relatives are even better at dodging antibodies, both in vaccinated and those who have recovered from the original Omicron. ..
The first booster people are supposed to strengthen immunological memory and help explain why hospitalization and death protection proves to be more durable. .. When the virus slips through the antibody, various defenders called T cells begin to work, attacking the infected cells and controlling the disease.
"T cells recognize the virus in a radically different way," looking for a portion of the virus that hasn't changed much, rather than a disguised peplomer. increase. Wherry.
Still, as people grow older, all parts of the immune system gradually weaken. There is little data on how long T cell protection against COVID-19 lasts, or how it is altered by various mutations and vaccines.
Wherry and dozens of other scientists recently asked the FDA to stop focusing solely on antibodies and start measuring T cells when deciding on a vaccination strategy. did.
The Biden administration needs Congress to provide more money if the FDA clears the updated boosters so that the government can buy enough for all Americans who want it. It was revealed that there is. Also, Dr. Anthony Fouch, the government's top infectious disease expert, told Congress last week that he was better off with a nasal version that could better block nasal infections and a more variability-resistant shot. He said more research funding was essential to create a generational vaccine.
"The virus is changing and we need to keep up with it," Fauci said.
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The Associated Press's Department of Health Sciences is supported by the Science Education Department of the Howard Hughes Medical Institute. AP is solely responsible for all content.
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