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It is time to update coronavirus vaccines to better match the options currently driving the pandemic, external experts told the Food and Drug Administration on Tuesday.
Independent scientists and doctors supported an updated omicron vaccine with 19-2 votes. Despite the overwhelming agreement that it was time to change the vaccine, many experts said they felt frustrated and embarrassed by the need to make a quick decision to prepare for the fall with limited data.
Companies need several months to produce a new vaccine, so the deadline for choosing a vaccine formula to be ready for release in October has come. The FDA is expected to issue a final decision in the coming days.
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But no one knows what options will be circulating this winter, and it’s reasonable to expect that any version of omicron included in the updated vaccine will be in the rearview mirror by the time the photos hit a weapon. Updated vaccines that include BA.1 have been in human trials for months, but this variant is spreading this winter and has already been overshadowed by other versions of omicron; sub-options BA.4 and BA.5 already account for half of the cases in the United States.
There is also uncertainty about whether updated vaccines will really protect people better. The companies have shown that they have been able to elicit moderately higher levels of antibodies that block the virus, but it remains unknown whether this will lead to better protection against hospitalization or infection. The hope is that the updated vaccine will expand the immune response.
“We more or less want to have a crystal ball today,” said Arnold Monto, acting chairman of the FDA’s advisory committee and honorary professor of public health at the University of Michigan School of Public Health.
During the discussion, many committee members said that the vaccine should be a multi-strain vaccine that includes the original version of the virus and a component of omicron. Many FDA members and staff preferred the BA.4 and BA.5 omicron sub-options, but some saw a promise to include the omicron BA.1 version.
“I think given the speed of evolution [of the virus] we’ll be behind the eighth if we wait longer, “said Mark Sawyer, a professor of clinical pediatrics at the University of California, San Diego School of Medicine. “Public opinion is that the FDA is already delaying approvals. I think we have enough data presented today to move forward with a change in tension. “
Vaccine companies, including Moderna, Novavax, Pfizer and its German partner BioNTech, provided sometimes conflicting data on potential enhancement strategies, leaving commission members to triangulate between overlapping, sometimes different, results.
Paul Ofit, a vaccine expert at Children’s Hospital of Philadelphia, called the data “uncomfortably scarce” and voted against changing the strain. He questioned whether the modest difference in the way modified vaccines elicit an immune response was a big enough difference to make it a benefit to humans.
“I don’t think it’s fair to ask people to take risks … if we don’t feel comfortable with the level of protection we are likely to get,” Ofit said.
Each of the companies presented data in support of their preferred strategy.
Moderna, for example, prefers a bivalent vaccine adapted to protect against the original version of the virus and the omicron BA.1 variant. The company said it could start delivering the vaccine this summer, but warned that a vaccine that includes BA.4 and BA.5 could take until late October or early November.
However, Pfizer and its German partner BioNTech have found that a vaccine that targets a single variant of the virus, BA.1, is better than a divalent formulation. The company also presented data on mice, suggesting that a vaccine adapted to control omicron subvariants, which is expected to dominate soon in the United States, BA.4 and BA.5, may provoke stronger and broader immune responses. The company will be ready to deliver each version of the vaccine by the first week of October.
The Novavax vaccine is not yet approved in the United States, but it uses a different technology – it delivers viral protein prepared in a laboratory. The company provided data suggesting that additional doses of its existing vaccine may be protective, even against omicron subvariants. Clinical trials of its omicron booster are ongoing, with results expected in September.
Adam Berger, director of clinical and health research at the National Institutes of Health, said the data presented at the meeting suggested that while the universal recommendation to change vaccines was preferred for simplicity, the result set suggested that “no No is a universal answer to whether a voltage change is needed.
Several experts have expressed concern that if the United States changes its vaccine composition, it could exacerbate global problems with vaccine fairness and perceptions of vaccines. It was also unclear whether the change in the vaccine would apply to adults or to children. Several experts said that if the vaccine is changed for children, they would like to see more tests.
But during the public consultation session, several parents passionately asked for the vaccines to be updated for all age groups, including the youngest children.
The wait for vaccines for children under 5 was “long and painful,” said Kate Schenk, a mother of three. “We cannot allow this to happen again. Children must be eligible to receive these updated boosters along with older cohorts – not lagging behind, unprotected. “
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Peter Marx, director of the FDA’s Center for Biological Substances Assessment and Research, said half of Americans had not received a booster, despite clear evidence that a third injection renewed and extended protection. Even those who have received boosters will become vulnerable again over time as their immunity declines.
“The better the matching of vaccines with the circulating strain, we believe it may correspond to improved vaccine efficacy and potentially better durability of protection,” Marx said.
But even an updated vaccine will not reset the pandemic and provide perfect protection against a rapidly evolving and highly transmissible virus. Omicron subvariants, which are already growing in frequency today, are unlikely to be the ones the world will face in the fall. How well vaccines based on them will protect against future iterations of the virus will not be fully known until they are used.
The process is compared to choosing a flu vaccine each year. For several years it has been a better match with circulating influenza strains than others.
But the flu is a different virus, and the meeting is an early step in the long-term challenge of trying to develop a vaccination strategy.
“I will remind you that the parallel path of influenza strain selection, which works very well, has been a process that has been perfected for many, many years. So we probably have a lot of work to do, “said Jerry Weir, director of viral products at the Vaccine Research and Review Service. “It’s a different virus. We have a lot of work to do in the process of selecting strains for covid vaccines. ”
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