Any vaccine maker, including Pfizer that has sought emergency-use authorisation for its Covid-19 shot in India, must conduct an additional local study to be considered for govt approval, news agency Reuters has reported quoting a senior government official. In December, Pfizer had sought govt approval to import and distribute its vaccine in India without doing local trials. Serum Institute of India, which is manufacturing the Oxford vaccine, did a months long local study on more than 1,500 people before seeking and receiving emergency approval on January 3.