Renewed COVID-19 vaccines are poised to fight the super contagious omicron variant.
On September 1, US health officials greenlit the first major update to mRNA-based injections, reformulated to recognize both the original version of SARS-CoV-2 and recently circulating versions of omicron . Those mRNA vaccine boosters could start working in a matter of days.
“They can help restore protection that has diminished since previous vaccination and were designed to provide broader protection against newer variants,” said Rochelle Walensky, director of the US Centers for Disease Control and Prevention. , in a statement after support the approval of a vaccine advisory committee of the shots
Both Moderna and Pfizer and its German partner BioNTech boosters created containing instructions for making the spike protein from the BA.4 and BA.5 omicron subvariants, as well as the spike protein from the original virus (Serial number: 06/30/22). Those two variants now account for almost all new cases in the United States. The United States Food and Drug Administration granted emergency use authorization for injections on August 31. The CDC action means Pfizer’s booster is now approved for those 12 and older; The Moderna opportunity is for people over 18 years of age.
the European Medicines Agency Y Health Canada it also authorized the use of an updated booster vaccine on September 1. That one, made by Moderna, contains mRNA instructions for building the original coronavirus spike protein and the omicron BA.1 subvariant spike protein. The UK, Switzerland and Australia have already given the go-ahead for the use of that dual or bivalent booster.
Here’s what you should know about the new vaccines:
Should I get a booster shot?
Probably. The CDC now recommends that everyone over the age of 12 who is fully vaccinated receive the bivalent vaccine, as long as it has been at least two months since their last dose of vaccine. “If you are eligible, there is no bad time to get your COVID-19 booster and I strongly encourage you to get it,” Walensky said.
That recommendation comes regardless of how many boosters people have had.
“If you see this as a big change … you’re right,” Evelyn Twentyman, who heads the CDC’s vaccine policy unit, said Sept. 1 during the vaccine advisory committee meeting. “We want to emphasize that we are no longer looking at the total number of doses,” she said. Starting now, the agency hopes to transition to a more regular schedule for COVID-19 vaccinations, similar to annual flu shots.
The original vaccines will continue to be used for the first two doses, but the bivalent vaccines will replace the previous boosters for all children except those aged 5 to 11 years. Pfizer’s original vaccine booster is still available for that age group, but bivalent vaccines may arrive later this year for children up to 6 months of age.
This time there was another big difference: the decision to go ahead with the BA.4/5 boosters was made without data from human trials. These trials are underway, but the results will not be known until the end of the year.
By authorizing new boosters without clinical trial data, agencies are treating COVID-19 vaccines more like annual flu shots.
Data collected from people immunized with the BA.1 boosters and data from studies of mice inoculated with the BA.4/5 vaccine were used as evidence for the likely safety and efficacy of the new boosters. The European Medicines Agency said at a press conference on September 2 that also use the BA.1 booster to evaluate the new shots.
Why are the shots aimed at the BA.4 and BA.5 omicron sub-variants?
“We very deliberately chosen BA.4/5said Peter Marks, director of the FDA’s Center for Biological Evaluation and Research, which oversees vaccines, at a press conference on August 31.
Both companies have tested vaccines based on the omicron BA.1 variant in humans. But BA.1, which caused the massive surge earlier in the year, is no longer circulating in the United States. Beginning the week of August 21-27, BA.5 was projected to cause approximately 89 percent of COVID-19 caseswith BA.4 variants responsible for about 11 percent of cases.
“This gives us a variant that is more up-to-date and probably more like something that may evolve further in the fall,” Marks said. “The more up-to-date it is, the better chance we have of [the vaccine] working for what comes next.”
All omicron subvariants share common mutations. But the shape of the spike protein of BA.4/5 looks very different to the immune system than other omicron subvariants, the CDC’s Natalie Thornburg said at the advisory committee meeting. Those differences can train immune cells to build a wider variety of antibodies that can latch onto a wide range of variants.
Mice inoculated with a booster containing BA.4/5 had less virus in your lungs than mice that received BA.1 boosters, Moderna’s Jacqueline Miller said at the CDC meeting. The mice produce a human version of ACE2, the protein on the surface of cells that the coronavirus uses to enter. Mouse studies of earlier booster variants corresponded well to the levels of protection seen in human clinical trials, Miller said, so the company is hopeful that the BA.4/5 booster also provides good protection.
Bivalent vaccines work better (increasing antibody levels in people and animals) than those that contain only the original spike protein or only a variant spike protein, Miller said. The spike protein that attaches to human cells is a three-pronged claw. With the bivalent vaccine, each prong could be an original version or an omicron. Mixed clawing can expose parts of the spike to the immune system that are normally hidden, Miller suggested.
Because right now?
Although the mouse data suggests the BA.4/5 booster will work, some of the CDC advisers said they would feel more comfortable having data from ongoing human clinical trials before recommending the new injections. That data could be available in a couple of months, so why not wait?
The wait could cost lives and money, computer projections suggest. The COVID-19 Scenario Modeling Center, a consortium of pandemic forecasters predicting COVID-19 patterns over the next six months under varying conditions, considered what would happen in the United States if boosters were administered in September or not until November. Waiting would lead to 137,000 more hospitalizations and 9,700 more deathsthe researchers projected.
A booster campaign in early autumn could save more than $62 billion in direct medical costsan analysis of Commonwealth Fund projects.
It is safe?
According to studies with the BA.1 bivalent booster, yes. That shot produced similar secondary effects as the original shots.
And it is also safe to get flu shots and other vaccines, including those used against monkeypox, at the same time as the COVID-19 booster. In fact, doctors should offer all the vaccines a person is eligible for in the same visit, said Elisha Hall of the CDC.
Some data indicates that the potential for serious side effects, such as inflammation of the heart called myocarditis, occurs at similar or lower rates with boosters than with second doses of mRNA vaccines. The side effect is rare; CDC has verified 131 cases of myocarditis from more than 126 million booster doses given, reported Tom Shimabukuro of the CDC’s COVID-19 Vaccine Safety Unit. The rate of myocarditis is 1.8 to 5.6 times higher after COVID-19 infection that after vaccination for males ages 12 to 17, the group for which the condition is at highest risk, said Sara Oliver of the CDC. Spacing the booster at least two months after the last dose of the vaccine may help prevent any increase in myocarditis, Marks said at the FDA news conference.
“We have a great deal of experience with the original monovalent vaccine,” FDA’s Doran Fink said during the CDC advisory meeting. That experience made the FDA comfortable in extrapolating data from the BA.1 booster trials to decide that the new injections are also safe.
“We typically don’t have a lot of clinical information … when we think about changing flu vaccines,” said Sarah Long, an infectious disease pediatrician at Drexel University School of Medicine in Philadelphia. Much like the flu shot reshapes last season’s version, the updated COVID-19 booster is based on the same scaffolding as the original version. “It is part of the same roof. We’re just putting up some dormers and windows.”
Pablo Sánchez, a pediatric infectious disease physician at The Ohio State University and Nationwide Children’s Hospital in Columbus, cast the only vote against recommending the BA.4/5 boosters. Other committee members voted to recommend reinforcements but expressed reluctance to do so.
“I really don’t want to set a precedent of recommending a vaccine for which we don’t have clinical data,” Sánchez said. He added: “I’m sure the vaccine will probably be as safe as the others,” but having the human data can help counter any doubts about the vaccine.