Speaking on a radio program, Nip – who oversees the city’s mass inoculation drive – said the government would consider using a new batch of the vaccines if they were safety concerns with the existing ones.

“We hope those who need to get a second dose will be able to take their shots before mid-April,” said Nip, who said officials would give priority to those who need their booster jab.

But he said that the arrangement can only be made once the findings are released.

His remarks came a few days after the government halted injections of BioNTech

on Wednesday, as frontline staff reported packaging problems with some of the vials.

Recipients of the BioNTech jabs are expected to get their booster shot 21 days after they received their initial dose, but those appointments have been cancelled.

Nip said health authorities had determined that the second dose of BioNTech can be administered anywhere from 19 to 42 days after the first injection, so there would still be time for officials’ investigation.

Vaccination workers had found 57 instances of vials with defects, such as cracks in containers, loose caps and stains on the glass exteriors.

However, the vaccines inside the problem vials had not been put to use yet, and the government has stressed the would not be any safety risks.

Nip added health authorities had been urging BioNTech’s mainland distribution agent Fosun Pharma to investigate the matter quickly.