Serum Institute of India (SII) may have to adjust the composition of AstraZeneca/Oxford vaccine that it is manufacturing, after the World Health Organisation’s (WHO) Strategic Advisory Group of Experts on Immunization (SAGE) on Monday and Tuesday showed concern over effectiveness of the vaccine against South African mutant coronavirus strain.The SAGE was reviewing the evidence on the vaccine’s effectiveness on new virus SARS CoV-2 variants and made significant recommendations in the backdrop of the decision of South Africa to halt the rollout of the Oxford-AstraZeneca vaccine after preliminary clinical trial findings of a study published by the Wits Vaccines and Infectious Diseases Analytics Research Unit indicated the vaccine offered.