WASHINGTON — A panel of independent experts advising the Food and Drug Administration will on Tuesday make its recommendation on whether to update existing COVID-19 vaccines to target a newer version of the coronavirus in a booster shot that could hit Americans in the fall . can get it
The federal government hopes to improve the vaccine to boost people’s immunity against a possible resurgence of the virus this winter. But for it to move faster, it may have to abandon the lengthy human trials that have been used to test coronavirus vaccines for the past two years in favor of a faster process that combines laboratory testing and animal testing. Depends more on testing.
Recent human volunteer trials have lasted five months, even when relatively small groups were used. But the virus is evolving so rapidly that new vaccine formulations are already out of date before such studies are complete.
Pfizer and Moderna, the two major vaccine makers, are both studying an updated vaccine targeting the Omicron variant that became dominant last winter. Both companies took a financial risk and began manufacturing this updated version, betting that the government would choose it as the fall amplifier.
But Omicron itself has been overtaken by a series of subtypes that began about three months ago, and many scientists argue it’s a chronic threat.
“Omicron is clearly in the rearview mirror,” says Dr. Peter J., vaccine specialist at Baylor College of Medicine. said Hotez. A booster targeting Omicron doesn’t make sense, he said, unless it also works against the latest subvariant, “I haven’t seen any evidence of that.”
In a Tuesday meeting, the FDA will ask the advisory panel whether a withdrawable vaccine should be a target for a variant of the Omicron-family virus. That would leave it up to federal regulators to decide which wording to use in the fall.
Scientists initially had high hopes for a so-called bivalent vaccine that would combine the existing formulation with a formulation targeting Omicron. Clinical trial results released this month by Moderna and Pfizer with their partner BioNTech found that it elicited higher levels of antibodies to Omicron than existing vaccines.
But when the companies released the results, outside scientists weren’t impressed with the less than doubled growth. A virologist at Beth Israel Deaconess Medical Center in Boston, Dr. Dan H. Barouch, described it as “relatively minor”. And the FDA said in a new briefing document for the Advisory Committee that Omicron’s bivalent targeting is “already a bit out of date.”
Federal authorities could instead push for a bivalent vaccine that targets BA.4 and BA.5, two subtypes of Omicron. They now account for more than a third of infections in the United States and could resemble any autumn incarnation of the virus.
But even a dichotomy aimed at these subtypes would be problematic. Neither Pfizer nor Moderna have focused on developing one, and no one knows for sure how well it will work. At the end of the year, the use of human trials for such a vaccine, followed by the two months it would take for dosage formulation, could release any new vaccine into the next wave of the virus.
This suggests officials will need to base their decisions largely on animal and laboratory testing.
dr Kelly L., President of Immunize.org, a nonprofit group dedicated to increasing immunization rates. Moore said such a rapid process is already being used to update the flu vaccine every year.
While this is the country’s first trial of next-generation Covid vaccines, he said, the existing ones have been safely administered to hundreds of millions of people. Updating them might require “very educated guesswork,” he said, but such conclusions are “reasonable in the circumstances.”
If the government wants a booster shot of the BA.4 and BA.5, they will still try to produce cans by the fall, despite accelerated testing. According to two people familiar with the company’s operations, Pfizer may be able to meet the October deadline.
But dr Paul Burton, Moderna’s medical director, said in an interview last week that the company is unlikely to be able to ship doses by the end of this year or early next year. “I don’t think we’ll be able to be ready to support the Fall Booster campaign,” he said.
There is also a possibility that the virus could evolve again and render the updated vaccine ineffective.
“Are we aiming for BA.4 and 5? They’ll likely peak somewhere in the next month or two,” said Dr. , a clinical research director at the National Institutes of Health. John Beigel, who has conducted multiple coronavirus vaccine trials. “They could be old news by the fall.”
dr Beigel said one option is to simply stick with existing vaccines, which offer strong protection against serious diseases but little against infection.
The Centers for Disease Control and Prevention estimated that by February, 60 percent of Americans had already been infected with the virus, giving them at least temporary immunity. While breakthrough infections are now common in vaccinated individuals, many cases are mild.
Still, the World Health Organization said this month that updated versions of vaccines should be investigated as protection against symptomatic disease is rapidly declining.
dr Beigel and other public health officials say the virus is more agile at evading antibodies, which are the first line of defense against infection. Studies show that current booster doses reduce levels of neutralizing antibodies to BA.4 and BA.5 significantly less than those to Omicron.
On average, 255 Americans still die from Covid every day, and about 4,400 are hospitalized. The FDA’s briefing document says the risk of another major COVID outbreak later this year will increase “due to a combination of weakened immunity, advancement of variants, and increased indoor activity.”
The advisory panel will likely be split between those who believe a fall booster will be necessary across the board and those who limit additional shots to high-risk individuals. dr Arnold Monto, a professor of public health at the University of Michigan and chair of the panel, predicted that booster shots would be offered to a broad segment of the population.
“We know something is going on,” he said in an interview. “We need to promote, and it’s better to promote something more relevant” than existing vaccines.
At the other end of the spectrum is Dr. Paul Offit, a vaccines specialist at Children’s Hospital of Philadelphia. “Hospital stays are less. Deaths have gone down as we are protected from serious diseases,” he said. “that’s what counts.”
He said only those over 70 and those over 50 with serious underlying conditions would need a booster shot, as COVID infection can have serious consequences in these groups.
Ultimately, the amount available to the government can determine the scope of a new booster campaign. Congress rejected a White House request for $22.5 billion in coronavirus emergency funds and a settlement plan to spend $10 billion from April has stalled. The government has transferred $5 billion in funds for coronavirus testing and protective gear to buy new vaccines.
“With the resources we can gather to get vaccines together for the fall, it’s very clear that we won’t have enough vaccines for every adult,” said Dr. Ashish Jha from the White House. That’s what the coordinator of the pandemic response said at a briefing last week.