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The US Food and Drug Administration is expected to authorize the first updated versions of the COVID-19 booster since the pandemic began this week.
The new shots are modern and improved versions of the Pfizer-BioNTech vaccines. They are known as “bivalent” vaccines because they are designed to protect against the original strain and the highly infectious Omicron variant.
Specifically, vaccines are programmed to target the BA.4 and BA.5 omicron subtypes, which are the major strains that infect people and are most efficient at sneaking around the immune system.
It is expected that the shots will strengthen people’s weakened immunity and provide strong protection against catching the virus, spreading it and getting sick from COVID and prolonged COVID.
The Biden administration plans to make new shots available after Labor Day to help cushion the impact of another surge of infections this fall and winter.
“This is a really important moment in this pandemic,” Dr. Ashish Jha, the White House COVID-19 response coordinator told NPR. “This is the first major upgrade to vaccines — the first major change in vaccines — in the last two and a half years.”
But the process of manufacturing and authorizing the boosters has sparked debate among scientists.
For the first time, the FDA is deciding how well vaccines work without the results of tests done directly in people. To save time, the FDA is initially evaluating the vaccines with tests in mice, along with results from trials that were done on people from an older version of a bivalent vaccine.
Some experts worry that mouse studies not very reliable in predicting how well vaccines work in people.
“This could be problematic if the public felt that the new divalent boosters are a super-strong shield against infection, and therefore increased their behavioral risk and exposed themselves to more viruses,” he says. john moorean immunologist at Weill Cornell Medicine.
But federal officials defend the decision.
Mouse studies suggest that the new vaccines can be about 20 times more protective against Omicron than the original shots, and about five times more protective than the first attempt at creating an Omicron-specific bivalent vaccine, Dr. Peter MarxThe director of the Center for Biologics Evaluation and Research at the FDA told NPR in an interview.
“This gives us confidence that they will do what they intended to do, which is to generate a good immune response against the BA.4/5 variant, as well as improve our overall response given the vaccine’s core component.” It’s refreshing,” says Marks.
The decision to rely on mouse studies became necessary after the FDA in June rejected a new booster targeting the original strain of Omicron, known as BA.1, and instead asked vaccine companies to use those strains. Said to develop new shots targeting that had replaced it.
Some scientists believe that there is a possibility that the new shots may also give people immunity that lasts longer than the original shots, and perhaps even protect against new variants being exposed. But more research is needed to confirm this.
Some experts say that data from the BA.1 booster indicates that any potential improvement may be quite minor.
“We want a silver bullet. And the booster has become the silver bullet. And we’re putting all our eggs in the vaccine basket,” Dr. Celine GounderSenior Fellow of the Kaiser Family Foundation. “I highly doubt how much these vaccines will improve population immunity and serious disease prevention.”
Gounder also worries that the country has given up doing little to protect people, such as wearing masks and improving ventilation.
But others are more optimistic about the new booster.
“I’m personally very excited about bivalent vaccines,” says Jenna GuthmillerAssistant Professor of Immunology at the University of Colorado.
“We need an updated vaccine to provide protection against current Omicron lineage viruses as well as potentially any future Omicron variants,” says Guthmiller. “I think it’s going to be good.”
After the FDA authorizes the vaccines, advisors from the Centers for Disease Control and Prevention will meet on Thursday and Friday to decide whether to recommend it and who should receive it. CDC Director Dr. Rochelle Valensky must sign off on that recommendation.
Some experts say that only people who are at high risk because of their age or underlyingYes Health problems need to get another booster because the first shots are still protecting most people from serious illness. Others say that everyone age 12 and older who hasn’t been infected or boosted recently should get a new shot.
“I would say that anyone who has been on more than six months since their last boost or last transition should get a boost,” says E. John Varyan immunologist at the University of Pennsylvania.
“Any opportunity to get more boosters into the population to scale up the vaccine is going to be a positive thing to do to help us tackle this pandemic,” says Veri.
The Biden administration has purchased more than 170 million doses of the new booster, which should begin to become available after Labor Day.
It’s not clear how much demand for the new boosters will be, given that many eligible people still haven’t received their first or second booster.