The Ministry of Health and Family Welfare has extended the duration for taking the second dose of Covishield to 12-16 weeks from the current 6-8 weeks. This change has only been recommended for Covishield while the second dose of indigenously produced Covaxin has to be taken in 28 days after the first dose.
This recommendation to increase the dose was given by the COVID-19 working group headed by Dr. N.K. Arora, also called the National Technical Advisory Group on Immunization along with five other members. After analysing a study published in the Lancet, which suggests that the vaccine's efficacy- its ability to fight the virus- is better if the duration between the two doses should be close to three months, the group recommended this change. This recommendation has been accepted by the Ministry as well as the National Expert Group on Vaccine Administration headed by Dr. V. K. Paul, member, NITI Aayog.
The study suggests that the vaccine efficacy after the first dose stayed at 76% between 26 to 90 days and the antibodies started waning after the 90th day. Vaccine efficacy increased to 81% when the second dose was given after 90 days. This same efficacy after a period of six weeks hinged around 55%. "A 3-month dose interval might have advantages over a programme with a short dose interval for roll-out of a pandemic vaccine to protect the largest number of individuals in the population as early as possible when supplies are scarce, while also improving protection after receiving a second dose," reads the study.
Other Recommendations By The NTAGI
The working group has also made two other recommendations to the NEGVA along with extending the duration of the second dose of Covishield.
One of the recommendations is related to vaccinating pregnant and lactating women in the country. Currently, India considers pregnancy and lactation as a contraindication for both the vaccines. The Oxford-AstraZeneca as well as the Covaxin trials did not include these categories of women. The NTAGI has recommended that pregnant and lactating women be given the vaccine.
The other recommendation is about vaccinating individuals who have been diagnosed with COVID-19. The government recommends those who have tested positive to register for the vaccine after a period of 4-8 weeks. The NTAGI committee, however, has asked the ministry to review and change this to 6 months post testing positive.
The Ministry is yet to make any decisions or announcement on the other two recommendations.