New Delhi: Union Health Minister Dr Harsh Vardhan on Sunday said that Serum Institute of India and Bharat Biotech are expected to begin late-stage clinical trials of intranasal Covid-19 vaccines in the coming months once they receive regulatory approval.

The late-stage trial usually involves thousands of participants, sometimes 30-40,000, Harsh Vardhan said.

According to the World Health Organization (WHO), all the vaccines which are currently in phase-3 trials are administered by injection.

On Saturday Dr Reddy’s Laboratories Ltd and Russian Direct Investment Fund (RDIF) said they received renewed approval to conduct late-stage clinical trials in India of Russia’s coronavirus vaccine ‘Sputnik V’.

Covid-19 cases increased by another 61,871 in India over the past 24 hours, data released on Sunday showed, although the health ministry said it is seeing a trend of steadily declining active cases.

The Indian Council of Medical Research (ICMR) reportedly said it will revisit its protocol for Covid-19 treatment after the WHO found some of the commonly used drugs, including remdesivir, had little or no impact on a patient’s chances of surviving.