A Russian agency and an Indian pharma company announced on Wednesday their plans to conduct an efficacy trial of the Russian candidate vaccine against the coronavirus disease in India and distribute 100 million doses for mass vaccination campaigns.

The Russia Direct Investment Fund, the country’s sovereign wealth fund, and the Hyderabad-based Dr Reddy’s Laboratories have partnered for clinical trials and distribution of the vaccine after approval from the Indian drug regulatory authority, the two entities said.

“Upon regulatory approval in India, RDIF shall supply 100 million doses of the vaccine…. Deliveries could potentially begin in late 2020 subject to completion of successful trials and registration of the vaccine by regulatory authorities in India,” the RDIF and the DRL said in a statement.

Russia had approved the candidate vaccine, named Sputnik V, after phase 1 and phase 2 safety and immunogenicity studies. A critical round of phase 3 efficacy studies to test the vaccine’s capacity to protect people from the infection is under way in Russia with 40,000 healthy volunteers.

“The phase 1 and phase 2 results have shown promise. We will be conducting phase 3 trials in India to meet the requirements of Indian regulators,” DRL managing director G.V. Prasad said in the statement.

Vaccine researchers say a clinical trial in India, if approved by the regulatory authority, would likely involve a few thousand healthy volunteers. The proposal to distribute 100 million doses is intended to support a mass vaccination campaign, the researchers said.

“They are meant for population-wide general use — a mass vaccination campaign,” a spokesperson for the RDIF told The Telegraph, adding that an application for the clinical trials in India would be filed soon.

The application will need to be filed with the Central Drugs Standard Control Organisation (CDSCO), India’s regulatory authority for drugs and vaccines. Under standard procedures, any mass vaccination can only start after the results of phase 3 trials have been assessed as successful.

However, the CDSCO can under certain exceptional circumstances approve “emergency authorisation” use for either a drug or a vaccine ahead of standard trial requirements.

India’s health minister Harsh Vardhan had on Sunday hinted that the Centre might consider emergency authorisation of Covid-19 vaccination “especially in the case of senior citizens and people working in high-risk settings”.

Senior health officials had said earlier this week that the CDSCO had not yet received any proposal for emergency authorisation of a Covid-19 vaccine.

“We believe our human adenovirus dual vector platform will provide a safe and scientifically validated option to India in the battle against Covid-19,” Kirill Dmitriev, RDIF’s CEO, said.

Russia is also looking to use India as a source of mass production of the vaccine for which the RDIF is in talks with several vaccine makers, a spokesperson said.

The Russian agency said over 55,000 volunteers had applied to take part in post-registration trials. The first results of these trials are expected to be published in October or November.

“The data in their scientific paper look impressive,” said Sudanshu Vrati, a senior virologist and director of the Regional Centre for Biotechnology, Faridabad (Haryana).

“But the actual proof of protection from the infection will only come from phase 3 trials.”

The phase 1 trials primarily assess the safety of the vaccine while phase 2 trials are intended to find out whether a candidate vaccine will generate an immune response in the recipients. In the phase 3 trial, the candidate will be assessed for its capacity to protect the recipients from future infection.

India is also independently assessing two home-grown vaccines, currently in phase 2 trials, and an Oxford-made vaccine in phase 3 trials.