What did new studies show?

The studies focus on a small number of subjects and were reported on preprint servers, ahead of peer review. They follow a similar format: Researchers took blood from people after vaccination with the new booster or the old one, sometimes including people with previous infection. They compared the virus-fighting antibodies — a key line of immune defense — in those different groups against different variants. Two studies came to nearly identical conclusions. A group from Beth Israel Deaconess Medical Center in Boston and a team from Columbia University and the University of Michigan found that all boosters increased antibodies, but the benefit of the bivalent was similar to the older booster, even against BA.5, the strain that most closely matched the new vaccine. That’s disappointing, because there was hope that updating the vaccine would produce a much stronger response. “I think everyone had hoped that a BA.5-based boost would enhance that [immune] response. But that’s not what we saw,” said David D. Ho, a professor of microbiology and immunology at Columbia who led one of the studies . Studies from Emory University and the University of Texas Medical Branch made similar comparisons, but found that the antibodies generated by the bivalent booster had an advantage against BA.5, supporting the case for a bivalent booster. These differences lead scientists to debate the clinical relevance of those findings, the differences between the tests used in each experiment and the variations among blood samples tested. The important takeaway is that none of these studies undermine the case for a booster. They make a bit of an artificial comparison, pitting the new boosters against an additional shot of the old booster. They do not compare the new boosters to not getting boosted at all — a path that many Americans are now taking, sparking worry among public health officials. They also followed only a small number of subjects for a short period, and it is possible that larger studies or longer follow-up will help scientists understand if bivalent boosters help the immune system develop new memories.

What do we know about the new boosters and how well they will work against new variants?

Omicron spinoffs are threatening to dominate this winter, and the bottom line is that all of them look like a big challenge for the antibodies generated by vaccines and infections. Antibodies are a key line of immune defense, but not the only one, against the virus. The Emory study, for example, suggests that bivalent boosters may help broaden immunity in the right direction, so the drop-off in protection against these challenging new variants isn’t as steep as it would be if people got additional boosters of the original. “Bivalent vaccines and omicron infections are providing broader and greater breadth of immune response,” said Mehul Suthar, an associate professor at the Emory Vaccine Center. But all the studies show a major drop-off in antibodies’ ability to block the virus with the new vaccines. That’s not good news, but it’s probably not catastrophic, either. Vaccines teach the entire immune system to fight a virus, not just antibodies. Many scientists expect additional layers of immune defenses will still help prevent severe illness and hospitalization.

How does this change what we already knew about these boosters?

When Food and Drug Administration officials were debating what formula to use for boosters in June, the data was sparse. But it all pointed in the same direction, suggesting that updating the vaccine was probably not going to be a game changer in terms of the short-term immune response. Moderna and Pfizer and its German partner, BioNTech, presented data showing that when people were given boosters based on an earlier version of omicron, they mounted a slightly better immune response — at least in test-tube studies. But the difference was modest , and it was unclear whether it had any bearing on whether people would be better protected. The new studies, which looked at the actual bivalent boosters being used, found that the degree of benefit is in the same modest range as those initial studies suggested. Most important, these are all laboratory experiments that give hints about how well vaccines work but don’t allow scientists to make precise predictions about whether people will become infected or end up in the hospital. Scientists have debated whether the modest difference in antibody levels would lead to any meaningful difference in a person’s likelihood of getting infected or sick. This uncertainty is what motivated Paul A. Offit, a vaccine expert at Children’s Hospital of Philadelphia and member of an FDA advisory committee, to vote against changing the booster recipe this summer. But the committee voted overwhelmingly for a switch to a booster that contained an omicron component.

What does this mean for me — should I get the booster?

Even scientists who are critical about the choice of composition for the new booster believe there are benefits to getting boosted — particularly for people at high risk of severe illness because of age or underlying health conditions. John P. Moore, a professor of microbiology and immunology at Weill Cornell Medicine in New York, just got a booster of the Novavax vaccine . His main worry is that public health officials eager to get people vaccinated are overselling the benefits of the bivalent booster, potentially fueling the perception that these new vaccines will guard against any infection. “No one is saying don’t get boosted. The concern that I have is if you talk up these bivalent boosters as being some kind of super strong shield … that encourages people to believe they’ve got amazingly strong protection against infection,” Moore said. “My message for the general public is: Don’t drop your guard just because you’ve been boosted.”

Health

What you need to know about covid boosters and the latest research

By Carolyn Y. Johnson

Updated November 2, 2022 at 5:30 p.m. EDT|Published October 27, 2022 at 6:00 a.m. EDT

New studies are fueling debate about whether the booster shot targeting the BA.4 and BA.5 versions of omicron is superior to another shot of the original. (Hannah Beier/Reuters)

Each time a new coronavirus variant looms, scientists across the world race to perform laboratory tests to understand how a key line of human immunity will hold up.

These experiments can’t answer the questions most ordinary people have: How well will my booster protect me? But they provide essential clues to guide vaccine strategy.

Get the full experience.Choose your plan

A handful of small studies are out on the bivalent booster shots that were rolled out in September and are designed to better match the current phase of the pandemic by incorporating components from the original version of the virus and from the BA.4 and BA.5 omicron subvariants.

The new studies show a similar picture, though there are variations in how the experiments were conducted and even bigger differences in how scientists interpret them. The studies suggest, overall, that the short-term immune responses are similar whether from a new or old booster. Both shots boost immunity, with the bivalent shots having a bit of an advantage, depending on which data you review — but they aren’t transformative.

Getting boosted today is a good idea to top off immunity. With a swarm of immune-evading subvariants looming on the horizon, the available boosters remain the best tool to help fortify protection, particularly against severe illness and death. But it’s looking ever more likely that the immune-evading variants that are gaining a foothold will cause a wave of infections this winter, even in people who have been boosted.

Coronavirus: What you need to know

Vaccines: The CDC recommends that everyone age 5 and older get an updated covid booster shot. New federal data shows adults who received the updated shots cut their risk of being hospitalized with covid-19 by 50 percent. Here’s guidance on when you should get the omicron booster and how vaccine efficacy could be affected by your prior infections.

New covid variant: The XBB.1.5 variant is a highly transmissible descendant of omicron that is now estimated to cause about half of new infections in the country. We answered some frequently asked questions about the bivalent booster shots.

Guidance: CDC guidelines have been confusing — if you get covid, here’s how to tell when you’re no longer contagious. We’ve also created a guide to help you decide when to keep wearing face coverings.

Where do things stand? See the latest coronavirus numbers in the U.S. and across the world. In the U.S., pandemic trends have shifted and now White people are more likely to die from covid than Black people. Nearly nine out of 10 covid deaths are people over the age 65.

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