NEW DELHI: The government has accepted the COVID-19 Working Group's recommendation for extending the gap between the two doses of the Covishield vaccine from 6-8 weeks to 12-16 weeks, the Union health ministry said, while announcing the extension on Thursday.
However, no change has been suggested for the dosage interval for Covaxin, it 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," the ministry said.
The present gap between two doses of Covishield, manufactured by the Serum Institute of India, is 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), headed by Dr V K Paul, Member (Health), Niti Aayog, in its meeting on May 12, 2021," the ministry said.
It has accepted this recommendation of the COVID-19 Working Group of extension of the gap between the first and second doses of Covishield to 12-16 weeks, the health ministry added.
The health ministry has now advised states and union territories to ensure second dose of Covishield to beneficiaries within this stipulated time interval of 12-16 weeks after first dose.
Paul at a press conference said that extending the gap between the vaccine's two doses was a science-based decision taken on the recommendations of the National Technical Advisory Group on Immunisation (NTAGI).
Explaining the reasons behind the extension, he said according to studies, initially the interval between two doses of Covishield was 4-6 weeks but then as more data became available, secondary analysis showed increasing the dosage interval to 4-8 weeks can have some advantage.
The UK by that time had already extended it to 12 weeks and the World Health Organisation (WHO) also had said the same, but many nations still did not change the dosage pattern, Paul said.
"At that time, our science-based technical committee anchored by ICMR (Indian Council of Medical Research) along with the DBT (Department of Biotechnology) by looking at the data available felt breakthrough infections may increase if the gap is increased (to 12 weeks). So, in good faith, based on their capability, without any pressures, they increased the dosage interval to 4 to 8 weeks," he said.
The issue was reviewed periodically again and again, Paul said.
Now, based on the available real-life evidence, 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, adding that this is a dynamic decision and part of a periodic review.
Underlining that NTAGI is a standing committee which was constituted much before COVID-19 had emerged and works on immunisation for children, Paul said, "It looks at scientific data and we must respect the decision of this institution."
"They make independent decisions. Have faith in our scientific processes. NTAGI is a group of individuals of high integrity," he said.
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 is not a problem at all."
On ensuring the extension of the gap between the two doses of Covishield, Union Health Secretary Rajesh Bhushan in a letter to states and union territories said, "I request you to kindly instruct the concerned officials to undertake necessary steps to widely disseminate the message of revised dosing interval amongst programme managers, vaccinators and recipients of Covishield vaccine and ensure adherence of revised dosing interval."
"Requisite changes are being carried out in the Co-WIN platform and would be separately communicated to the States/UTs. You are also requested to note that this decision of revised time interval between two doses is applicable only to Covishield and not to Covaxin vaccine," he said.
The COVID-19 Working Group is chaired by Dr N K Arora, who is director at the INCLEN Trust.
Its members comprise Dr Rakesh Agarwal, Director and Dean, JIPMER, Puducherry; Dr Gagandeep Kang, professor, Christian Medical College, Vellore; Dr J P Mulliyal, former 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).