NEW DELHI (AP) — The Serum Institute of India said Tuesday that it hopes to start delivering coronavirus vaccine doses to the U.N-backed effort known as COVAX and to other countries by the end of the year, a delay that will significantly set back global efforts to immunize people against COVID-19.

India’s Serum Institute, the world’s biggest vaccine-maker and the main supplier of COVID-19 vaccine doses to COVAX, said in March that it was postponing all exports of coronavirus vaccines to deal with the explosive surge of cases on the subcontinent.

At the time, the World Health Organization and Gavi, one of the partners in COVAX, said they expected COVID-19 vaccine deliveries from India to resume by June and the interruption would affect about 90 million doses.

“SII has delivered more than 200 million doses,” the Serum Institute said Tuesday in a statement posted to its Twitter account. The company said that in the past few days, there had been “intense discussion” on the decision of the Indian government and vaccine manufacturers about the possible export of vaccines.

“We continue to scale up and prioritize India,” the company said. “We also hope to start delivering to COVAX and other countries by the end of the year.”

In April, as many as 60 countries had their immunization plans stalled because postponed supplies from COVAX meant most had no other source of COVID-19 vaccines.

Serum Institute CEO Adar Poonawalla previously warned that if the coronavirus crisis in India did not subside, “I am scared of what...we will have to do, and what will happen.”