AstraZeneca vaccine likely won’t be authorized in US until April

The coronavirus vaccine developed by AstraZeneca and Oxford University is not likely to be authorized for use in the U.S. until April, a top Trump administration health official said Wednesday.

“We project, if everything goes well, that the readout and emergency use authorization may be granted somewhere early in the month of April,” Moncef Slaoui, the chief science adviser for the administration’s Operation Warp Speed, told reporters.

The April estimate from Slaoui is a change from earlier this month, when he told reporters he expected an emergency authorization could come in February. The U.S. has already purchased 300 million doses of the vaccine.

Britain on Wednesday became the first country in the world to authorize the vaccine for emergency use, but it was partly based on unpublished data because of the way the U.K. reviews the trial.

In an effort to push out as many doses of the vaccine as possible, British officials said they would not hold back doses. Instead, they will prioritize giving people the first dose and delay the second shot for as long as three months. 

The vaccine has the potential to be a global difference-maker in the fight against COVID-19. AstraZeneca has promised to make as many as three billion doses available in 2021, which is far more than any other manufacturer. The company has also pledged not to make a profit on the vaccine, so the cost is also much cheaper.

The vaccine also can be transported and stored for months with normal refrigeration, unlike the two authorized vaccines from Pfizer and Moderna.

In the U.S. though, health officials have raised questions after promising early results turned out to be the result of a dosing error. 

The shot has a 62 percent effective rate if given in two full doses 28 days apart like it was for most participants. The company found the drug to be 90 percent effective when a small group in the trial was mistakenly given half a dose initially, followed by a full dose.

Slaoui expressed some concern with the data but indicated the ultimate decision would be up to the Food and Drug Administration (FDA).

“The biggest question mark, frankly, is efficacy in the elderly population. That needs to be further documented just because there were not enough … of the subjects recruited into trial,” Saloui said.

Slaoui also questioned the true efficacy of the drug. AstraZeneca has said that the combined “pooled” numbers amount to an average of 70 percent efficacy, but Slaoui said he thinks the FDA would not be satisfied with that explanation.

“We need a clear and concrete number, more than a number that is, you know, accumulated by putting together different trials with different schedules and different materials,” Slaoui said.