Are the new boosters that target omicron better than the previous shots?
Even if the boosters aren't any better than the original vaccine, health experts say they should be effective at helping restore some of the immunity that has faded since people got their last shots or infections.
President Joe Biden rolled up his sleeve in front of reporters at the White House on Tuesday to get one of the new COVID-19 bivalent boosters. The event was part of the administration's campaign to encourage more people to get one of the shots before another possible surge.
The vaccines are the first to target the omicron variant and are being promoted as providing better protection than the original shots. But are they more effective? Two recent studies, the first with direct data from people, suggested the vaccines may work as well as the original but are not superior.
To save time, emergency use authorizations for these mRNA boosters from Moderna and Pfizer- BioNTech were based on how well the shots stimulated the immune system and on tests on mice.
So, researchers at Columbia and Harvard compared how the immune systems of volunteers responded.
About a month after being injected, the new boosters did not stimulate significantly higher levels of antibodies that could neutralize the BA.4 and BA.5 subvariants currently infecting most people.
“To disappointment, the bivalent vaccine did not show superiority over the original vaccine,” says Dr. David Ho, a professor of microbiology and immunology at Columbia.
The results follow announcements this month from Moderna and Pfizer-BioNTech suggesting the boosters would provide better protection.
Even if the boosters aren't any better than the original, health experts say they should be just as effective at helping restore some of the immunity that has faded since people got their last shots or infections. That could be lifesaving, especially for those who are most vulnerable, like the elderly.
Deepta Bhattacharya, a professor of immunobiology at the University of Arizona, says the new studies were too small and too short to reach any firm conclusions. Larger studies will be needed.
“For those who are saying, see, see, I told you so, I would say, let's stand down a little bit and wait for some cleaner data to come out because these studies can't be used to support, really, one argument or another,” Bhattacharya says.
Might larger and longer studies could show the boosters provide longer-lasting immunity or even help people fight off new variants? Immunologist John Wherry at the University of Pennsylvania says people have to be realistic.
“It's a little bit of a - sort of a reality check or a reset that the bivalent vaccines are not a magic bullet. They're not going to give us, you know, perfect protection from these new omicron variants that are circulating,” says Wherry.
Biden’s event on Tuesday was staged in hope of getting more people to receive the booster. Only about 20 million people have, even though more than 200 million have been eligible since Labor Day.