pune public health experts citing emerging evidence have said that india could consider delaying the second dose of the covid vaccine to improve immunogenicitycurrently the followup shot is being given 28 days later experts toi spoke to said the country could look beyond that timelinedr gagandeep kang a member of strategic advisory group of experts sage which is advising the world health organization said the decision to delay was not just about supply constraints but improved efficacy too a recently published lancet study said the oxfordastrazeneca vaccine made in india by serum institute as covishield showed greater efficacy when its second dose was administered after a gap of 12 weeks instead of four the study was based on results from over 17000 trial participantsthe researchers found that efficacy of the shot had risen from an average of 551 after two doses were given fewer than six weeks apart to 813 when the interval was at least 12 weeksdr kang said results from the clinical trials with the oxfordastrazeneca vaccine show a longer interval between doses improves immune response and improves the efficacy of the shot for this vaccine then based on the data we now have it makes sense to have an interval of at least eight to 12 weeks between doses dr giridhara rao member of the national covid19 task force said there is now enough evidence to prove theres better efficacy after eight to 12 weeks i strongly urge the indian government committee to reconsider the timeframe for the second dose he said dr vijay natrajan ceo of the symbiosis university hospital and research centre said the lancet suggests a threemonth interval between doses is advisable it will boost immunity but in the indian context the risk of contracting covid in the 90 days between doses remains high thats why the government picked 28 days or four weeks however as a nation we can claim the best of both immunity and protection if we strictly follow covid precautions during the 3month period and beyonddr lalit kant former head of icmrs epidemiology and communicable diseases division said models have shown a delayed second dose offers better protection but realworld conditions can differ delayed doses can protect a higher number of people quickly when supplies are limited but in india we dont seem to have a shortage of vaccines so the benefit is in terms of improving the level of protection he saiddr kant added a closer look at the data in the lancet study shows the sample size was too small to draw a meaningful conclusion therefore studies with adequate sample sizes are needed before we can think of changing indias vaccination schedule for covishield