Serum Institute of India, the world's largest vaccine producer, said on Thursday it has made 40 million doses of AstraZeneca's potential Covid-19 vaccine, and would soon begin making Novavax's rival shot, as they both seek regulatory approval.

Serum said it had enrolled 1,600 participants in India for late-stage trials of AstraZeneca's candidate, and also plan s to seek regulatory approval to run late-stage trials for the Novavax vaccine.

The AstraZeneca vaccine, co-developed by Oxford University, is the most advanced in human testing in India, Serum said, adding that the company and the Indian Council of Medical Research (ICMR) will pursue ‘early availability’ of the shot in India.

Representatives for both Serum and the ICMR declined to comment on whether the 40 million doses of the AstraZeneca vaccine were meant for supply only in India.

The ICMR, a federal government body, had funded the clinical trial site fees for the AstraZeneca vaccine, Serum said. The company and the ICMR are currently conducting mid-stage clinical trials of the shot at 15 centres across India.

The news came as coronavirus infections in India, the world's second-worst hit country, reached 8.68 million on Thursday and the death toll increased to more than 128,000.

India also has at least two home-grown Covid-19 vaccine candidates in development, while local drugmaker Dr Reddy's Labs is carrying out a trial in the country for Russia's vaccine candidate.

Earlier this week, Pfizer and its partner BioNTech said their vaccine candidate had proven more than 90% effective based on initial trial results. Pfizer said it was committed to advancing its engagement with India's government to supply its potential vaccine in the country.