The coronavirus vaccine developed by AstraZeneca and the University of Oxford is unlikely to be authorized for use in the United States until April, a senior official in the Trump administration said on Wednesday.
“We project, if all goes well, that reading and emergency use authorization may be granted somewhere in early April,” said Moncef Slaoui, the government’s chief scientific advisor to Operation Warp Speed.
Slaoui’s April estimate is a change from earlier this month, when he told reporters he hoped an emergency clearance could arrive in February. The United States has already purchased 300 million doses of the vaccine.
On Wednesday, Britain became the first country in the world to authorize the vaccine for emergency use, but it was partly based on unpublished data due to the way the UK analyzes the trial.
In an effort to distribute as many doses of the vaccine as possible, British officials said they would not withhold doses. Instead, they will prioritize giving people the first dose and postponing the second injection for up to three months.
The vaccine has the potential to make a global difference in the fight against COVID-19. AstraZeneca has promised to make up to three billion doses available in 2021, which is much more than any other manufacturer. The company has also pledged not to profit from the vaccine, so the cost is also much cheaper.
The vaccine can also be transported and stored for months with normal refrigeration, unlike the two vaccines authorized by Pfizer and Moderna.
In the United States, however, health officials raised questions after the first promised results turned out to be the result of a dosing error.
The injection has an effective rate of 62% if administered in two complete doses 28 days apart, as it was for most participants. The company found that the drug was 90 percent effective when a small group in the trial mistakenly received half a dose initially, followed by a full dose.
Slaoui expressed some concern about the data, but indicated that the final decision would rest with the Food and Drug Administration (FDA).
“The biggest question mark, frankly, is effectiveness in the elderly population. This needs to be more documented just because there were not enough … of the individuals recruited for the trial,” said Saloui.
Slaoui also questioned the real effectiveness of the drug. AstraZeneca said that the combined “pooled” figures average 70% effectiveness, but Slaoui said he thinks the FDA would not be satisfied with that explanation.
“We need a clear and concrete number, rather than a number that is, you know, accumulated by assembling different tests with different schedules and different materials,” said Slaoui.