As Covid-19 vaccine makers prepare vaccines specific to Omicron, federal health officials say there are signs they may not be needed.
Research continues, however, and industry and global health officials say doses targeting the new, highly transmissible variant may be needed in the longer term, especially if it eventually crowds out earlier strains around the world.
Differing opinions on the need for Omicron-targeted vaccines highlight continued uncertainty around the relative effectiveness of current vaccines against the variant weeks after it began sweeping the United States
Researchers designed existing Covid-19 vaccines to fight the original strain of coronavirus that predominated in 2020. Since then, the vaccines have remained effective against newer variants like Delta that have emerged and overtaken the original strain.
Omicron’s push in the US has raised concerns that vaccines may need to be modified to specifically target the strain, as existing vaccines don’t appear to work as well against it, leading to more breakthrough infections. .
Compared to the original coronavirus strain first identified in China, Omicron has a large number of mutations on the spike protein that could make it resistant to currently licensed vaccines, scientists say. In an effort to stay on the safe side, drugmakers including Pfizer Inc.,
its partner BioNTech SE and Moderna Inc.
prepare modified plans.
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US health officials say there are practical reasons why targeted Omicron injections might not be helpful and there’s a good chance they won’t be needed to deal with the current surge. of Covid-19.
“The reason for having an Omicron-specific vaccine is if you thought it would be the new normal – the new variant that will take over and keep circulating over time,” Peter Marks, Food’s Top Vaccine and Drug Administration regulator, said. “By the time we have made an Omicron-specific vaccine, this wave will be over.”
The researchers also want to see how the immune responses generated by a targeted injection of Omicron compare to those of the original vaccines. For now, according to some infectious disease experts, existing vaccines appear capable of protecting against serious illnesses caused by Omicron as long as people are given booster shots, although research is continuing.
“We have strong evidence that with a boost, current vaccines work well,” said John Mascola, director of the Center for Vaccine Research at the National Institute of Allergy and Infectious Diseases. He and other scientists collaborated with Moderna to evaluate its Omicron vaccine.
Dr. Marks said the next two months should show whether Omicron is likely to prevail over the long term, outperform other strains like Delta, or fall back quickly like previous variants. For now, that uncertainty means there are risks and costs to pushing new vaccines prematurely, he and Dr. Mascola said.
““We have strong evidence that with a boost, current vaccines work well.””
Pharmaceutical companies would have to start revamping their manufacturing processes and facilities to make new vaccines, which would disrupt the production of current vaccines needed to immunize people around the world, Dr Marks said.
“You don’t want to disrupt something unless you’re damn sure you actually need it,” he said.
However, industry executives and global health officials have indicated that an Omicron-specific vaccine or additional boosters will likely be needed eventually. While current mRNA-based vaccines like those from Pfizer and Moderna appear to protect against serious illness after a booster, the protection could wane over time.
A World Health Organization technical advisory group said on Tuesday that current vaccines may need to be updated to provide sufficient protection against infections and diseases caused by variants such as Omicron.
Pfizer CEO Albert Bourla said “the most likely scenario” is for the company to move to manufacturing a targeted shot at Omicron that is also effective against earlier variants.
“I think we’ll be almost ready to drop [for authorization] and launch, if successful and if we need it, in March,” Bourla said at the JPMorgan Healthcare conference on Monday.
An FDA spokeswoman declined to comment on Bourla’s remarks.
Moderna CEO Stephane Bancel has said at recent investor conferences that the current recall protection against Omicron may diminish over time. He said he expects people will need another dose of Moderna’s vaccine in the fall, and it’s possible he’ll target Omicron alone or more than one strain. The drugmaker said it plans to start a clinical trial of its Omicron-specific booster early this year.
““We’re in this kind of Sisyphean game of always advancing the variant of the day until it’s needed or not.””
the maker of a new vaccine that is not yet licensed in the United States, began manufacturing an experimental Omicron vaccine in December to test its use, in case the company decides to begin clinical trials in the first quarter, said said a spokeswoman.
Novavax medical director Filip Dubovsky said the company can prepare new variant-specific versions of its Covid-19 vaccine relatively easily and has done so before when new strains have emerged, although none have emerged. has been necessary so far.
“We’re in this kind of Sisyphean game of always advancing the variant of the day until it’s needed or not,” Dr. Dubovsky said.
Government health officials say they would like to know if new Omicron vaccines are as effective as current vaccines against other variants, as strains like Delta continue to circulate and could rise again or evolve into even more variants. recent later.
It would take companies about three months to complete the studies needed to assess the potency of their vaccines against other variants and support an FDA clearance, Dr. Marks said. He added that the risk of a new vaccine not being as effective as current vaccines is a matter “that could keep me up all night for a long time”.
In the longer term, the search for variants highlights the need for a next-generation vaccine that could combat various SARS coronaviruses and several variants, including known strains and those to come, according to some health experts.
Still, some infectious disease doctors doubt that any “pan-coronavirus” vaccine will prove effective in the near future, citing researchers’ difficulties in developing pan-influenza vaccines.
The US military’s Walter Reed Army Institute of Research is developing an experimental Covid-19 vaccine that could potentially work against multiple variants. It began a small, early-stage clinical trial of the vaccine last year, and the results are awaited.
For biotechnology Inc.
and GlaxoSmithKline PLC are collaborating to develop a pan-coronavirus vaccine targeting multiple variants of the current coronavirus as well as future coronaviruses that may emerge.
The companies’ scientists aim to make a vaccine that would not only work against all variants of the virus, but provide protection for up to years, compared to months for current vaccines, said Skip Virgin, chief scientific officer of Vir.
“If we could get three to five years [of protection], that would be a big step forward,” he said.
—Jared S. Hopkins contributed to this article.
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