The New York Times, veteran personal health columnist Jane E. Brody cited the original roll-out of the Salk polio vaccine in 1955 as a reminder of how the premature release of a vaccine can cause more damage than good. “A mishap in mass-producing the vaccine caused polio in 70,000 children, permanently crippling 164 of them and killing 10," she writes.We look at some key questions related to the development of Covaxin, and whether or not it is scientifically (and ethically) possible to achieve it in a short span.What is Covaxin?Bharat Biotech’s Covaxin is an indigenous, inactivated vaccine that is being developed in collaboration with ICMR’s National Institute of Virology (NIV), Pune.