India, April 7 -- Hyderabad-based Bharat Biotech announced last week that it is working on developing a nasal drop vaccine for Covid-19. Animal testing has begun in the US in collaboration with virologists at the University of Wisconsin-Madison and vaccine developer FluGen. Bharat Biotech's chairman and managing director Krishna Ella spoke to Rhythma Kaul about trials for the new vaccine, how the animal testing phase will be crucial, the delivery mechanism, and the challenges that vaccine manufacturers face in India....