MANILA, Philippines — The Department of Health (DOH) said yesterday that it is waiting for an explanation from AstraZeneca regarding the reported errors during the trials of its vaccines against COVID-19.

At a press briefing, DOH Undersecretary Maria Rosario Vergeire noted they expect an official statement from the United Kingdom-based pharmaceutical firm.

“We are waiting for the manufacturer because they have that responsibility,” she added.

AstraZeneca had filed an application to conduct clinical trials in the Philippines for its COVID-19 vaccines.

“We have ongoing negotiations with them. So it is but right that they are responsible to provide us with the adequate information as to these allegations regarding their study,” she said.

Earlier, AstraZeneca had announced that its vaccine had achieved 90-percent efficacy rate against the novel coronavirus. But the firm eventually admitted that there were dosing errors during the trials.

Some patients reportedly got two full doses of the vaccine while others were administered half-dose in their first shot followed by a full dose in the second.

In London, AstraZeneca Plc is likely to run an additional global trial to assess the efficacy of its COVID-19 vaccine, according to the company’s chief executive Pascal Soriot, Bloomberg News reported on Thursday.

Instead of adding the trial arm to an ongoing US process, a new trial would be run to evaluate a lower dosage that performed better than a full amount in AstraZeneca’s studies, the report said.

AstraZeneca is facing tricky questions about its success rate that some experts say could hinder its chances of getting speedy US and EU regulatory approval.