BioNTech warned Tuesday there is no data backing the "safety and efficacy" of delaying the second shot of its Covid-19 vaccine beyond three weeks, as some countries push back the jab to give more people their first dose.BioNTech, which developed the vaccine with US giant Pfizer, said its clinical data showing 95% efficacy was based on a two-dose schedule separated by 21 days.Also Read | India’s hunt for the new Vision 2020"The safety and efficacy of the vaccine has not been evaluated on different dosing schedules," it said."Although data...
demonstrated that there is a partial protection from the vaccine as early as 12 days after the first dose, there is no data to demonstrate that protection after the first dose is sustained after 21.