WASHINGTON, United States (AFP) — President Donald Trump plans to issue a decree Tuesday aimed at granting Americans priority access to certain vaccines, but faced questions over whether the White House missed an opportunity to shore up sufficient doses in the months ahead.

President-elect Joe Biden will meanwhile announce his appointments and nominations for his health team as he continues to push ahead with the transition process despite Trump’s refusal to concede.

With COVID-19 inoculations expected to begin within days in the United States, the outgoing president will host what the White House is calling a “vaccine summit” to hail their rapid development and spell out details of the process.

The event follows a raft of positive news related to vaccines, including US regulators calling the Pfizer-BioNTech immunization — which Britain began rolling out on Tuesday — safe and effective in a briefing document.

The document further raised expectations that Pfizer will soon be granted emergency approval in the United States, with a meeting on the topic set for Thursday.

A meeting on emergency approval for US firm Moderna’s vaccine candidate is scheduled for December 17.

As coronavirus cases soar across the United States and states reinstitute varying levels of closures in response, the vaccines have provided hope to a country weary and grieving over the world’s highest pandemic death toll.

On Monday, an overwhelming majority of California’s residents went into lockdown, putting 33 million people under stay-at-home orders.

In the meantime, complex preparations are being made across the supply chain to be able to quickly deliver vaccines at the frigid temperatures required.

But while Trump has sought to take credit for vaccine development and eventual availability, The New York Times reported Monday that the White House had missed a chance to lock in the purchase of more Pfizer doses over the summer.

The US government has purchased 100 million doses of Pfizer’s vaccine in advance, with two doses required per person.

With the White House unwilling to extend that over the summer — before late-stage trials showed it was 95 percent effective — Pfizer sealed deals with other nations, the Times reported.

– ‘Sufficient number’ –

The report raised the question of whether the United States as a result will have enough doses for the entire population by the end of the second quarter of 2021 as the administration hopes.

Senior administration officials have called the report false and note other promising vaccines are also in development, particularly from Moderna.

Negotiations with Pfizer are also ongoing, and on Tuesday Oxford University and AstraZeneca became the first COVID vaccine makers to publish final-stage clinical trial results in a scientific journal.

“But we feel absolutely confident we will get the vaccine doses for which we’ve contracted, and we’ll have sufficient number of doses to vaccinate all Americans who desire one before the end of the second quarter of 2021,” a senior administration official said on condition of anonymity.

Pfizer and Moderna are not planning to attend Tuesday afternoon’s “vaccine summit,” but the White House says that’s because a top regulatory official will be there, which could pose a conflict of interest.

It is unclear what effect if any the executive order prioritizing Americans that Trump is planning to sign at the event will have.

Another part of the order may prove more practical as it is expected to address a process for how to assist other countries in need of vaccines.

A senior administration official described the executive order as “ensuring access to US government COVID-19 vaccines” and a “reaffirmation of the president’s commitment to America first.”

While Britain has moved ahead quickly on approving and distributing the Pfizer vaccine, the United States is likely to be close behind.

US health secretary Alex Azar has said he expects distribution could be possible within days after Thursday’s regulatory meeting, with priority populations receiving the first doses.

He expects the United States to have 40 million doses of both the Pfizer and Moderna vaccines available in December — enough for 20 million people.

Distribution will however be taking place as the country changes leadership, with Biden to be sworn-in on January 20 even though Trump, who has repeatedly downplayed the seriousness of the virus, continues to make baseless claims of electoral fraud.