WASHINGTON — The Biden administration now expects to launch a Covid-19 booster campaign with modified vaccines in September, as Pfizer and Moderna have promised to deliver doses by then, according to people familiar with the deliberations.
With updated formulations apparently close at hand, federal officials have decided not to qualify for second boosters of the existing vaccines this summer. The new versions are expected to outperform the now dominant Omicron sub-variant BA.5, although the data available so far is preliminary.
Until now, only Americans over 50 and those over 12 with certain immune deficiencies were eligible for second booster doses. While some federal officials have urged strengthening protections for younger Americans now, officials agreed on the goal of boosting everyone’s immunity in the fall with what it hopes will be a more effective booster, ahead of a possible winter wave of the virus. .
During internal deliberations, some senior health officials argued that eligibility for a second booster should be expanded before the reformulated version is ready as coronavirus infections rise again. dr. Anthony S. Fauci, the president’s chief medical adviser, and Dr. Ashish K. Jha, the White House Pandemic Response Coordinator, both advocated that position.
“I think there has to be flexibility and permissiveness to allow at least a second booster for younger Americans,” said Dr. Fauci in an interview this month. An alternative discussed was offering the shots only to a subset of younger, high-risk individuals, such as pregnant women.
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But officials from the Food and Drug Administration and the Centers for Disease Control and Prevention argued that the government should instead focus on the fall campaign with updated doses — if the campaign could start soon enough. After both Pfizer and Moderna recently assured the FDA that they would be able to deliver millions of doses by mid-September, regulators decided it was better to wait for those shots.
All adults are expected to qualify for the updated booster shots. Children could also be considered, according to people familiar with the deliberations.
The federal government also plans to continue to emphasize that anyone eligible for additional shots should get them now and not wait until the fall. By mid-week, health officials were still working out their specific advice on the reformulated shots.
One concern was making sure people didn’t get a booster too soon followed by another with the updated formulation. Officials feared that, especially for young men, two boosters in quick succession could increase the risk of a rare heart-related side effect, myocarditis, which has been linked to both Pfizer’s and Moderna’s vaccines.
For other reasons, immunologists warn against receiving booster shots at short intervals.
“You can’t get a vaccine on August 1 and get another vaccine on September 15 and expect the second shot to do something,” said Shane Crotty, a virologist at the La Jolla Institute for Immunology. “You have so many antibodies around, if you get another dose, it won’t do anything.”
“The antibodies make that next dose stop working” if the next dose is given too early, he added — a pattern that also applies to other vaccines, such as tetanus or flu shots.
Federal officials were also concerned about the public’s patience with additional shots. The number of recipients has decreased with each new one offered. While nearly half of those eligible for the first booster chose to get it, less than 30 percent of eligible Americans chose to receive the second booster — their fourth shot in all.
The Biden administration has been busy contracting the newly designed doses. The Department of Health and Human Services recently has bought an advance of 105 million doses of Pfizer-BioNTech’s $3.2 billion vaccine, timed for possible fall implementation. The administration is expected to finalize a similar arrangement with Moderna soon.
The government’s decision comes as the number of cases of the highly contagious BA.5 variant remains high across the country. Deaths and hospitalizations has arisen the past weeks. The number of new cases announced each day has hovered near 130,000 — probably a significant undercount due to the number of home tests that go unreported — and President Biden just had his own battle with the variant.
Deaths from Covid-19 are still highly concentrated among older age groups, while hospital admissions remain well below the peak of last winter’s Omicron wave.
At a meeting of an FDA advisory committee in late June, independent vaccine experts overwhelmingly agreed with the need to update the coronavirus vaccines, as the virus is now more adept at evading their protection. But both Pfizer and Moderna were reluctant to commit to delivering doses of a revised formulation at the beginning of the fall.
Kathrin Jansen, head of vaccine research for Pfizer, said at the meeting that her company was willing to provide doses in early October. dr. Stephen Hoge, the president of Moderna, said his company wouldn’t be able to deliver reformulated shots until late October or early November.
But recently, both companies assured federal officials they could speed up their schedules and be ready by early September, according to people familiar with the discussions.