The new COVID-19 booster with protection for Omicron at AltaMed Health Services in South Gate on Thursday October 6, 2022.
Sarah Reingewirtz MediaNews Group | Los Angeles Daily News via Getty Images
Two studies raise doubts as to whether the new omicron BA.5 booster will really offer better protection against Covid than the first-generation vaccine.
Scientists at Columbia University in New York City found that the new boosters did not elicit a better antibody response to BA.5 in humans than the first-generation vaccines. A separate study by researchers at Harvard came to essentially the same conclusion.
“It is important to note that the two studies were conducted independently. They’re small studies, but there are two of them – it’s not just a coincidence,” said Dr. Dan Barouch, the lead author of the Harvard study. Barouch’s laboratory played a crucial role in the development of the Johnson&Johnson Covid vaccination.
Both studies were published as preprints, meaning neither of them were peer-reviewed by others in the field. They analyzed samples from small groups, 21 people in the Columbia study and 18 in the Harvard study, who received the new boosters and compared them to people who received the old vaccine as a fourth shot.
dr Peter Marks, who heads the Food and Drug Administration’s vaccines division, said the preliminary studies have limitations because of their size. Data from larger, well-controlled trials are expected soon, Marks said. Pfizer and Moderna are currently conducting clinical trials of the new boosters, which are expected to read data later this year.
Marks said the Harvard and Columbia studies also showed that the new boosters are generally at least as good as the original vaccines at generating an immune response to omicron BA.5. If the boosters are even marginally better than old recordings, there would still be positive public health implications, Marks said.
“As such, the FDA continues to encourage eligible individuals to consider an updated vaccine to help protect against the COVID-19 variants currently circulating and the COVID-19 wave that appears to be coming,” Marks said.
dr Paul Offit, a member of the FDA’s independent Vaccine Advisory Committee, said public health officials should be cautious about selling the shots as a major upgrade.
“We have to be careful when we go before the American public and try to sell this vaccine as something significantly better when all the evidence we have so far doesn’t support it,” said Offit, an infectious disease expert at Children’s Hospital of Philadelphia , who worked on the team that developed the rotavirus vaccine.
Offit said the boosters work, they’re probably just no better than the old shots. In other words, vaccine recipients are likely to get the same level of protection that a fourth dose would receive with the first-generation vaccines, he said.
“The takeaway lesson is the people who have been in high-risk groups and will benefit from booster doses as we enter this late autumn and early winter – those who are immunocompromised, who have high-risk conditions, who are older – they should get that booster.” get dose,” said Offit, who is not involved in either study.
The Columbia and Harvard studies are well done and come from two of the top virology labs in the country, said Dr. Peter Hotez, co-director of vaccine development at Texas Children’s Hospital. But he described the results as preliminary.
“We have to be careful not to draw too many conclusions from this,” said Hotez, who also led a team developing an off-patent vaccine called Corbevax, which India approved for use last December.
Hotez said research should also be done on how the boosters stack up against emerging Omicron subvariants like XBB and BQ.1. subdued, since the currently dominant BA.5 is in circulation. It could be that the new boosters perform better against these new variants than the first-gen shots, Hotez said.
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The White House, the FDA, and the Centers for Disease Control and Prevention have repeatedly expressed confidence that the new boosters offer better protection than the old vaccines. This is because they are bivalent shots that directly target the dominant variant, omicron BA.5, as well as the original Covid strain that emerged in China in 2019.
The first-generation vaccines, on the other hand, are monovalent vaccines that only target the original Covid strain, which scientists call wild-type. Since the virus has evolved away from the wild type, the monovalent vaccines no longer offer any meaningful protection against infections and minor illnesses.
They still generally prevent hospitalization, although this protection also decreases over time.
“Based on what we know about the immunology and science of this virus, it is expected that these new vaccines will provide better protection against infection, better protection against transmission, and sustained and better protection against serious disease,” dr Ashish Jha, head of the White House Covid task force, told reporters in September.
Senior White House medical adviser Anthony Fauci also said at the time that the boosters should offer better protection than the old shots, although he said it was difficult to predict how much more effective they would be. This is because the Food and Drug Administration approved the bivalent vaccines in September with no direct human immune response or efficacy data on the BA.5 boosters.
Instead, the FDA relied on human data from a similar vaccine targeting the first version of Omicron, BA.1. Pfizer and Moderna originally developed their new boosters against BA.1, but the FDA urged the companies to change gears and target BA.5 as this subvariant became dominant over the summer.
As a result, Pfizer and Moderna didn’t have time to start clinical trials and submit data on the BA.5 boosters before approval. The FDA also relied on animal studies that looked directly at the immune response induced by the BA.5 shots.
The agency acted with urgency to get the new boosters out by autumn in hopes they would help stave off a major Covid surge.
The Columbia and Harvard scientists said their studies suggest a phenomenon called “imprinting” could pose a challenge for new boosters. This means your immune system is already primed by the monovalent vaccines to recognize wild-type Covid, which can make it difficult to train your body to recognize and attack new strains.
Hotez said it may be possible to overcome immune imprinting, if it is indeed a problem, by giving a second dose of the BA.5 shot at some point. In other words, the booster might not push a stubborn immune system trained to recognize the wild-type to shift gears and attack a new variant the first time. But a second dose might convince it to produce antibodies against BA.5.
But Offit said the antibodies that protect against mild disease are inherently short-lived. The real focus should be on preventing serious illness and hospitalization, which vaccines are successfully doing.
“You’re likely to keep getting mild illnesses with this virus, as is true for all short-incubation respiratory viruses — live with it,” Offit said. “We have to learn to live with that because that’s the only thing that’s achievable – keeping people out of the hospital.”
