Merck & Co Inc will help make rival Johnson & Johnson's single-shot Covid-19 vaccine in a partnership set to be announced on Tuesday by US President Joe Biden, a White House official said.
J&J's vaccine production has been slower than promised. Under its contract, the company was supposed to deliver 12 million doses by the end of February, but had less than 4 million ready to ship when the vaccine was authorized on Saturday.
It expects to be able to deliver another 16 million doses by the end of the month - still well short of its previous commitments - but will not ship any next week. The company has said it will be able to provide the full 100 million doses it has agreed to supply by its original midyear deadline.
The next shipments are waiting on regulatory approval of new manufacturing operations run by its partner, contract drugmaker Catalent Inc, J&J Chief Scientific Officer Paul Stoffels said in an interview on Monday.
Stoffels also said the company was looking for more partners to expand its production capacity. More doses sooner could speed the US vaccination effort considerably, because as a one-dose vaccine it is possible to inoculate twice as many people with the same number of shots. The other two US-approved vaccines - from Pfizer Inc and BioNTech and Moderna Inc - require two doses.
J&J's vaccine substance is made in the United States at a plant operated by Emergent BioSolutions Inc, as well as in facilities in the Netherlands and India.
There are two US factories - run by Catalent and Grand River Asceptic Manufacturing - where the vaccine is finished and put in vials. The company also has partners with fill-finish capacity in Spain, Italy, India and South Africa.
Merck's collaboration with J&J comes after Merck scrapped development of its own Covid-19 vaccine candidates in January, Merck last month said it was working on a deal to open up its manufacturing capacity to other vaccine makers.
The partnership is the latest example of large drugmakers working together to help produce Covid-19 vaccines to meet the global demand. Swiss drugmaker Novartis signed an agreement in January to fill vials for Pfizer and BioNTech's shot, while French drugmaker Sanofi SA will help fill and pack millions of doses of Pfizer's vaccine starting in July.
Merck will dedicate two US facilities to J&J's vaccine, according to a report in the Washington Post, which first reported the news of the arrangement on Tuesday.
"Merck remains steadfast in our commitment to contribute to the global response to the pandemic," the company said.
Biden is scheduled to speak on Covid-19 at 4:15 pm (2115 GMT)
J&J did not immediately respond to a request for comment.