The Health Ministry on Monday revised the interval between the first and second dose of Covishield vaccine to 4-8 weeks from the existing 4-6 weeks in its ongoing vaccination drive against the coronavirus.<\/p>\n\n\n\n
The Central government has written to States and Union Territories stating that in view of the emerging scientific evidence, the interval between two doses of a specific Covid-19 vaccine, Covishield, has been revisited by the National Technical Advisory Group on Immunization (NTAGI) and subsequently by National Expert Group on Vaccine Administration for Covid-19.<\/p>\n\n\n\n
The revised interval between two doses of Covid-19 vaccine is only applicable to Serum Institute of India\u2019s Covishield not to Bharat Biotech\u2019s Covaxin. The instruction has gone out after the evidence showed that protection was enhanced if the second dose of Covishield was administered between six and eight weeks but not later than that.<\/p>\n\n\n\n
According to data from trials of AZD1222 in other countries, the efficacy of the vaccine increased when the second dose was given more than six weeks after the first Its efficacy was around 54.9% when the second dose was given after less than six weeks of the first dose. It increased to 59.9% when the second dose was given after 6-8 weeks and increased to 63.7% when the second dose was at 9-11 weeks. The efficacy further jumped to 82.4% when the dosing interval stretched to 12 weeks or more. <\/p>\n\n\n\n
The government has taken up the step to partly address the concerns that vaccinations, despite the increase in sessions are not proceeding fast enough. The longer window between the two shots could potentially mean that more doses are freed up for a larger number of people to get their first dose of the vaccine sooner. <\/p>\n\n\n\n
The move came in the middle of the nationwide second phase of vaccination, in which people above 60 and those over 45 with comorbidities are being inoculated.The increase in intervals between the shot will also make it easier for the priority group population, which mostly consists of the elderly, to be vaccinated.<\/p>\n\n\n\n