Serum Institute CEO Adar Poonawalla tells NDTV that testing is underway to demonstrate the efficacy of the Oxford-AstraZeneca vaccine against the mutant strains of the coronavirus. Serum Institute is also looking to test the safety and immunogenicity of the vaccination among children. "Some of those vaccinated have been infected by the UK strain, but the cases are largely asymptomatic," says Adar Poonawalla. "90% effectiveness against hospitalisations has been validated," he adds.