Several vaccine experts said Novavax’s vaccine would help diversify the federal portfolio by including another candidate that uses a protein-based vaccine that has worked against other pathogens, like hepatitis B. The Novavax vaccine uses microscopic particles that carry fragments of the coronavirus, prompting the body’s immune system to respond. Sanofi, which has received nearly $31 million in government funding, is also developing a vaccine that is based on viral proteins.
Other leading candidates are relying on less proven technologies. For example, Moderna is using genetic material from the coronavirus called mRNA to provoke an immune response, and AstraZeneca and Johnson & Johnson are both testing vaccines that use a harmless virus to deliver coronavirus genes into cells.
“This is a sort of diversification from other approaches, which makes a certain amount of sense,” said John P. Moore, a professor of microbiology and immunology at Weill Cornell Medical College in New York City. “You don’t want all of your eggs in one basket.”
Mr. Erck said the deal with the United States would allow Novavax to begin manufacturing the vaccines before the company concludes late-stage clinical trials, expected by the end of the year. The company would ensure that 100 million doses — enough for 50 million people to receive an initial shot and a booster — are delivered by the first quarter of 2021, if its coronavirus vaccine is proved safe and effective. In June, Novavax secured a $60 million contract from the Defense Department to guarantee the delivery of 10 million doses to vaccinate American troops for the coronavirus.
Novavax began early-stage safety trials in Australia in May, and the company has said it expects to make the results available this month. It said it planned to begin so-called Phase 3 efficacy trials by the fall of this year and could release interim data by the end of 2020.
There is no vaccine for the coronavirus, and many clinical trials fail when vaccines turn out to be ineffective or to cause serious side effects. Until now, new vaccines have taken years to develop, and many experts have said the aggressive timelines set by companies and government officials for a coronavirus vaccine are overly optimistic.
Through its deal with the Coalition for Epidemic Preparedness Innovations, Novavax is also setting up manufacturing in other sites around the world, including in Europe and Asia, to serve populations outside the United States. The company is using its own facilities to scale up manufacturing and will also contract with outside companies, Mr. Erck said.