The expert said that such viruses, by their very nature tend to become less virulent over time, but there is no set timeframe for how long that would take.
Three weeks after people had been given a single dose of either of the vaccine, the rates of all COVID-19 infections fell by 65%.
No specific risk factors, including age, have been identified for thrombosis with the AstraZeneca shot, which could stem from an immune response, the European Medicines Agency (EMA) said.
Under IAVI's agreement with Merck KGaA and Serum Institute, the partners will conduct an accelerated, integrated program of preclinical and clinical research to evaluate the antibodies.
Three COVID-19 vaccine candidates, including two indigenous ones, are in different phases of development in India.