Johnson & Johnson is also in preliminary talks with Merck, a major American pharmaceutical company, about using its production lines, one of several ideas that federal health officials discussed with the Biden transition team. Federal officials are interested in boosting the nation’s vaccine-making power long-term, and Merck’s facilities may be among the few with remaining manufacturing capability.
But Dr. McClellan, who sits on Johnson & Johnson’s board of directors, said it would take months to adapt Merck’s factory to produce Johnson & Johnson’s vaccine. A senior administration official predicted that it could take until the end of the year.
Other vaccine makers may also come through by midyear. Novavax has worked to iron out what were recently dire manufacturing problems that delayed its clinical trials. Moncef Slaoui, the chief scientific adviser for the Trump administration’s vaccine development program, said in a recent interview that Novavax could apply for emergency use authorization in late April. The government has already ordered 110 million doses of the Novavax vaccine, to be delivered by the end of June, and Novavax has said it believes it can meet that target.
Mr. Biden has surrounded himself with new health officials assigned to getting vaccines from factories to recipients, including Dr. Bechara Choucair, the former Chicago health commissioner who is the White House’s vaccinations coordinator, and Tim Manning, a former top official at the Federal Emergency Management Agency who is now the supply coordinator. Dr. David A. Kessler, the former F.D.A. commissioner, will help lead the federal government’s vaccine development program at the Department of Health and Human Services, with special attention to manufacturing.
After both the Pfizer-BioNTech and Moderna vaccines proved to be highly effective in clinical trials late last year, the Trump administration considered whether to rethink its strategy of backing six different vaccine makers and instead throw all of its weight behind the proven producers. One senior administration official described “countless hours of debate” over the issue.
In the end, officials decided it was critical to keep aiming for a broad portfolio of vaccines, in part because no one has figured out which vaccines might work best for children or be most effective against emerging variants. They recommended that the Biden administration do the same.
Katie Thomas and Donald G. McNeil Jr. contributed reporting.