Issues related to the ramp-up of the AstraZeneca COVID-19 shot outside India for supplies to the COVAX vaccine-sharing facility have been resolved, UNICEF told Reuters on Tuesday, saying it should receive 65 million doses by end-May.

"The initial challenges related to release of vaccines due to ramping up a new supply chain and production across different continents have now been resolved," said the UN agency responsible for distributing vaccines through the programme.

"At this point, UNICEF expects around 65 million doses of COVID-19 vaccines from suppliers outside of India will be available for supply through the end of May to 80 countries."

It also expects to receive 50 million doses of the shot from the Serum Institute of India in May, compared with almost none this month as the company tries to meet demand in its home country that is battling a huge jump in infections.