The Serum Institute of India, the world's biggest vaccine maker, has applied to local authorities to conduct a small domestic trial of American vaccine developer Novavax's COVID-19 jab, which was found to be 89.3 per cent effective in a UK trial. It was also found to be highly effective against a variant first identified in the UK. But the positive Phase 3 clinical trial data was partly offset by other results that showed it offered significantly less protection against a highly transmissible variant of the coronavirus first identified in South Africa, which is spreading rapidly around the world.