Indian gave nod to emergency use authorization approval of Serum Institute of India (SII) and Bharat Biotech's Covid-19 vaccine last week. It is now being learned that any vaccine maker, including Pfizer, must conduct an additional local study to be considered for country's immunization programme.

According to news agency Reuters, Pfizer without conducting trials is looking forward to distribute its vaccine by importing in India. In December 2020, the American drug giant became the first firm in India to seek emergency approval by the Central Drugs Standard Control Organization (CDSCO).

"As of now, the pre-condition for any vaccine to be implemented in India is that you have to do a bridging trial," Vinod K. Paul, who heads a government panel on vaccine strategy told media.

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Indian health officials say the reason for so-called bridging trials is to determine if a vaccine is safe and generates an immune response in Indian citizens whose genetic makeup is different from people in western nations. There are, however, provisions under India's New Drugs and Clinical Trial Rules, 2019, to waive such trials in certain conditions.

The Pfizer vaccine which has been developed in partnership with Germany's BioNTech SE, is being administered to people in countries such as the United States and Britain.

Even though it was not immediately clear if any other countries had asked for similar smaller local trials before approving vaccines developed and tested abroad.

Dr Paul said Indian officials have had discussions with Pfizer and Moderna Inc – both US companies have reported more than 90% efficacy for their vaccines – to make the shots in India given its large pharmaceutical capacity.

Dr Paul who is a member of Niti Aayog also said that Russia's Sputnik V, which is now undergoing last-stage trials in India after completing a Phase 2 study there, will soon apply for emergency-use approval in the country.

No vaccine maker will be given indemnity by the government should something go wrong, Paul further said.

India with 10.5 million cases of total infections ranks second in the world after the United States.