The government on Thursday increased the gap between the two doses of the Covishield vaccine to 12-16 weeks following a recommendation from a government panel, and said it is a "science-based decision" taken with confidence that there will be no extra risk.
The ministry said, "Based on the available real-life evidences, particularly from the UK, the COVID-19 Working Group agreed for increasing the dosing interval to 12-16 weeks between two doses of Covishield vaccine. No change in interval of Covaxin vaccine doses was recommended”.
However, the National Technical Advisory Group on Immunisation (NTAGI) has suggested no change for the dosage interval for Covaxin, the Union health ministry said.
The present gap between two doses of Covishield, manufactured by the Serum Institute of India, is 6-8 weeks.
The Hyderabad-based Bharat Biotech's indigenously developed Covaxin and Oxford-AstraZeneca's Covishield, being manufactured by the Pune-based SII, are currently being used in India's inoculation drive against coronavirus.
The Central government's move comes amid reports from several states about shortage of COVID-19 vaccines. Some states and UTs have also reported that they had to suspend its vaccination drive for 18-44 years in view of the scarcity.
While Maharashtra decided on Wednesday to suspend its drive to vaccinate people in the age group of 18 to 44 years in view of vaccine shortage, Delhi also temporarily shut Covaxin-administering centres for this age group as it has run out of stock.
Several states and UTs including Delhi, Maharashtra, Karnataka and Telangana have also decided to opt for global tenders for procurement of anti-coronavirus shots with the domestic supply falling short to meet the rising demand.
Asserting that it has been a "science based decision" taken based on the recommendations of the NTAGI, V K Paul, member (Health) NITI Aayog said as per studies, initially the dosage interval between two doses of covishield was 4 to 6 weeks but then as more data became available secondary analysis showed increasing the dosage interval to 4 to 8 weeks can have some "advantage".
NTAGI is a standing committee which was constituted much before COVID-19 had emerged and works on immunization for children, Paul said, and added that "it looks at scientific data and we must respect the decision of this institution. They make independent decision."
They had seen that the UK by that time had already extended it to 12 weeks and WHO also had said the same, but many nations had not changed the dosage pattern, Paul noted.
At that time our science based technical committee anchored by ICMR along with DBT by looking at the available data felt breakthrough infections may increase if the gap is increased beyond eight weeks, Paul said.
"So in good faith, based on science, without any pressures, they increased the dosage interval to 4 to 8 weeks. Now based on the available real-life evidences, particularly from the UK, the decision to extend it from 6-8 weeks to 12-16 weeks has been taken with confidence that there will not be an extra risk" he said.
"This is a dynamic decision and, part of periodic review," Pauladded .
Asked if the efficacy of the vaccine will be affected with this extension, Paul said, "The efficacy is so good even after the single dose...it's not a problem at all."
This is the second time in the past few months that the interval between the two doses of Covishield has been increased. In March, the Union health ministry had asked states and UTs to increase the gap from 28 days to 6-8 weeks.
"The recommendation of the COVID-19 Working Group was accepted by the National Expert Group on Vaccine Administration for COVID-19 (NEGVAC)....in its meeting on May 12, 2021," the ministry said.
The COVID-19 Working Group is chaired by Dr N K Arora, who is director at the INCLEN Trust.
Its members include Dr Rakesh Agarwal, Director and Dean, JIPMER, Puducherry; Dr Gagandeep Kang, professor, Christian Medical College, Vellore; Dr Naveen Khanna, Group Leader, International Centre For Genetic Engineering And Biotechnology (ICGEB), JNU, New Delhi; Dr Amulya Panda, Director, National Institute of Immunology, New Delhi; and Dr V G Somani, Drugs Controller General of India (DCGI).
(With PTI inputs.)