Dive Brief:

• The U.S. government has reached a deal to acquire 100 million more doses of Pfizer and BioNTech’s coronavirus vaccine, giving the U.S. enough of a stockpile to vaccinate 100 million total residents. The vaccine is administered via two shots.

• Under the deal, Pfizer will deliver 70 million doses by the end of June and another 30 million by July 31 The U.S. also retains an option to acquire an additional 400 million doses of the vaccine. As with the original supply deal the two struck in July, Pfizer will receive $1.95 billion, suggesting a per-dose price of about $20.

• Pfizer and BioNTech’s shot is one of two to have received emergency clearance in the U.S., and has proven strongly effective at preventing COVID-19. But supplies in the U.S. are extremely limited, in part because the Trump administration and Pfizer were reportedly at odds over an expansion to their original deal.

Dive Insight:

The development and clearance of two highly protective vaccines in less than a year is a historic scientific achievement and a hopeful sign of the pandemic’s eventual end. That will only happen, however, if enough people are vaccinated.

In the U.S., a country with about 330 million people, that means making hundreds of millions of doses widely available. Getting there will likely require the success of several vaccines, not just the ones from Pfizer and Moderna. Until then, the speed at which Pfizer and Moderna can produce doses of their shots will be the limiting factor of a nascent immunization campaign.

Vaccine developers have worked feverishly to pre-produce as many doses as possible and cut deals to sell those doses before knowing whether their shots worked. Pfizer, for example, agreed in July to sell the U.S. 100 million doses of its vaccine, and gave the Trump administration an option to buy another 400 million.

But months went by without the U.S. agreeing to buy more doses from Pfizer, even after the company said in early November that its shot was 95% effective in preventing COVID-19. The New York Times later wrote that tensions had emerged between the Trump administration and the company, which reportedly offered to sell more but was turned down.

Unlike Moderna and several other vaccine developers, Pfizer didn’t accept U.S. funding for testing and manufacturing, a decision CEO Albert Bourla has said he made out of concern there’d be “strings attached.” Pfizer then announced the study data showing its shot worked shortly after the November presidential election, rather than in October, as it had originally projected. President Trump later accused the company of purposely delaying the data to damage his reelection bid.

The delay in negotiating for more doses appears to have cost the U.S. a chance at obtaining them sooner, as Pfizer agreed to deals with other governments that laid claim to supplies the drugmaker expects to produce in the first quarter of 2021.

The New York Times, which first broke news of the pending deal, reported Pfizer had asked the U.S. government to force its suppliers to prioritize its orders to help ramp up production. According to the Times, the administration initially balked at the request out of concern such a move would hurt developers that had accepted U.S. funding under the “Operation Warp Speed” program.

Pfizer expects to produce 50 million doses by the end of the year and as many as 1.3 billion in 2021. The pharma had initially set out to make 100 million doses this year, but was hampered by delays in getting raw materials, The Wall Street Journal reported.

Moderna, by comparison, anticipates making 20 million doses for the U.S. this month, with between 500 million and 1 billion manufactured for use globally next year.

Even if both companies meet their production goals, the U.S. and the world will need more developers to succeed. Vaccines from Johnson & Johnson and AstraZeneca, in particular, could deliver a crucial boost. Results from a Phase 3 trial of J&J’s shot are expected by the end of next month, while data from a similar study of AstraZeneca’s could come in February.

AstraZeneca, which licensed its vaccine from the University of Oxford, already has positive data from two late-stage trials in Brazil and the U.K., which could convince some regulators to clear the candidate for use.

But the data showed the vaccine’s efficacy differed across two dosing regimens, one of which was given mistakenly before the error was detected. As a result, it’s not clear which dose would be recommended for use, if any regulators chose to approve the shot. The large trial still underway and due to read out in February is testing the dosing regimen that appeared less effective.