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WASHINGTON — Federal officials said Wednesday that although some clinical trials have just begun, researchers trying to design an updated coronavirus vaccine for use this fall will have to agree on a formula by June to reach that deadline.
The assessment came during a day-long meeting of Food and Drug Administration external advisors, who came together to strategize on what the country’s coronavirus vaccine policy should look like going forward. The session underlined how deeply uncertain the road ahead is.
Among the most fundamental questions being debated: At what point will authorities decide that current vaccines are not working well enough? And if better vaccines are deemed necessary, when can clinical trials answer about suitable substitutes?
The meeting caught a crossing point for the Biden administration as it worked to craft a vaccine strategy for the remainder of this year. Some federal health officials believe existing vaccines need to be redesigned to provide better protection than they do now. They hope to have a revised version in the fall, when they fear a resurgence of the virus.
A senior federal official said the modified vaccine doses could cost the federal government about $5 to $12 billion. Congress has moved to roughly halve the administration’s demand for the new Covid budget, and it may not leave enough money to cover that cost, the official said.
At the same time, vaccine manufacturers and federal researchers are trying to figure out what a revised vaccine should look like. For example, a new study by the National Institutes of Health analyzes how Moderna’s vaccine works when revised to target three different variants, either alone or in combination. However, it has only just begun recruiting volunteers, with results expected this summer.
Robert Johnson, director of the infectious disease division within the Department of Health and Human Services, told the panel that even after regulators decide on a reconstituted vaccine, manufacturers will still need several months to produce a dose.
“If you don’t go to this clinical trial by early May, it’s very difficult to have enough products among manufacturers to collectively meet this demand,” he said. Overseeing vaccine regulation at the FDA, Dr. Peter Marks also described the timeframe as highly compressed, saying that regulators may need to agree on a new vaccine formula by May or June if they want to move on from existing vaccines.
The trials run are too small to provide efficacy data of the kind that have led to the approval of current vaccines. But they may produce enough data for federal health officials to determine whether a reconstituted vaccine will elicit a stronger or more sustained immune response—a metric used to understand efficacy.
At the meeting, expert after expert explained how predictive this effort was. No one knows what strain of the virus will dominate in the fall, when federal officials think a new surge is likely. Before then, there is a possibility that another variant, like the Omicron, will emerge and redraw the coronavirus picture in a completely unexpected way. “It’s unlikely, but it’s there,” said Dr. Marks about this possibility.
Trevor Bedford, biostatistician at Fred Hutchinson The Cancer Research Center said the coronavirus mutates at several times the rate of the flu virus, for which vaccines are redesigned each year. While that pace is slowing, the virus’ resilience means it is “likely to continue to evolve.”
How exactly he will do this, no one can predict. An immunologist at the University of Virginia School of Medicine, Dr. “There is no guarantee that every emerging variant will be the basis for the next,” warned Michael Nelson.
Meanwhile, federal officials and their outside advisers continue to grapple with what the threshold is to determine if current vaccines are not doing a good enough job. Dr. Marks said the consensus of the committee appeared to be that Covid vaccines should prevent serious illness, not necessarily infection or mild illness.
The question was particularly relevant because last week, the FDA, along with others, authorized a second booster for Americans age 50 and older. But the CDC director is outright recommended these shots only for anyone aged 65 or over and 50 to 64 years old with serious underlying health problems.
Some immunologists and vaccine experts said the FDA did not have the data necessary to authorize second supplements, while other health officials argued that people should have another vaccine option.
A committee member and president of Meharry Medical College in Tennessee, Dr. James EK Hildreth, Dr. He asked Marks why he didn’t seek the panel’s advice before deciding whether to allow a second booster.
Dr. Marks said the FDA does not consider recommending a second booster as “a major expansion or a major change.” Jerry Weir, another senior agency official, said he expects the FDA to ask the advisory panel to review any reconfigurations of existing vaccines before moving forward with emergency clearance.
Sharon Alroy-Preis, director of public health services at the Israeli Ministry of Health, told the panel: Applying a second booster for those 60 and older saved lives earlier this year. The Israeli submission seemed to support the FDA’s decision.
However, European Union regulators concluded on Wednesday He said it was “too early” to administer second booster vaccines to the general population, but that it was reasonable to recommend them to people aged 80 and over.
A senior CDC official, Dr. Amanda Cohn said her agency’s data show that current vaccines are more than 80 percent effective at preventing hospitalization in non-immune-deficient Americans, including the elderly and those with chronic medical conditions. He suggested that Covid treatments after infection may be more effective at protecting Americans from serious illness than supplemental vaccine shots.
University of Washington professor Dr. Christopher Murray predicted that antiviral therapies, such as pills recently developed by Pfizer, would reduce mortality rates even if a new variant emerges, as contagious as Omicron and as deadly as Delta. .
As director of clinical research at the NIH, Dr. John Beigel described his agency’s research comparing how well Moderna’s current vaccine worked against modified versions that target known variants, both alone and in combination.
In the first phase, the researchers hope to quickly enroll 600 volunteers who have already been vaccinated and have received boosters. Some will be given the current vaccine. Others will receive experimental vaccines targeting only the Omicron variant and three other variations: the Omicron plus Beta variant, the Delta variant, and the prototype virus that first emerged in the pandemic.
In an interview on Tuesday, Dr. Beigel said current vaccines may still be the best. He said he hoped the results of his trials could be ready by mid-summer, although some federal officials hoped it would be sooner.
“It will be tough,” he told the panel when deciding on the next step.
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