AstraZeneca plc’s covid-19 vaccine, the company on Monday said the jab showed an efficacy of 79% in phase 3 trial in the US, Chile and Peru, much higher than the results from the UK trial announced in November.Interestingly, the US trial data showed that the vaccine’s efficacy of 79% was achieved when two standard doses were given at an interval of four weeks, while data from UK trials showed an efficacy of 53% for interval of less than six weeks.Also Read | The invisible hand in India’s stock marketIn UK and Brazil, the efficacy was an average of 62%.
Due to some errors by Oxford researchers in the US, the actual efficacy varied between 53% and 90%, depending on the amount of dosage given and the interval between two doses.