The gap between two doses of the Covishield vaccine can be increased to 12-16 weeks, the Centre said on Thursday. Currently, the recommended gap is six to eight weeks.
The Centre said its decision was based on the recommendations by the COVID Working Group chaired by Dr NK Arora. However, no changes were made to the dosage regimen of Covaxin, whose recommended gap period is four to six weeks.
The National Technical Advisory Group on Immunisation also recommended deferring vaccination by six months after recovery for those who have been infected by coronavirus. The panel also said that pregnant women may be offered the choice to take any of the Covid-19 vaccines and lactating women are eligible for the shot any time after delivery, PTI reported.
The revised guidelines come even as several states experience a shortage of vaccine doses.
Serum Institute of India chief Adar Poonawalla welcomed the move and called it “a good scientific decision”, reported NDTV. “This is beneficial both from the efficacy and the immunogenicity standpoint,” he told the news channel. “This is a very good move because this is based on data that the government received on the basis of which they made a good scientific decision to increase the gap.”
Gap between Covishield doses
The revision in Covishield vaccine dosage is the third change in the regimen.
In March, the Centre had advised states and Union Territories to increase the interval between two doses to four to eight weeks, from the then prescribed gap of four to six weeks. Then in April, the Centre advised that the second Covishield dose could be taken 6-8 weeks after the first, according to The Indian Express.
A study published in medical journal Lancet in March, showed that the efficacy of the Covishield vaccine, initially developed by pharmaceutical company AstraZeneca rose to 81.3% when the two doses were given at a gap of 12 weeks, from 55.1% when administered less than six weeks apart.
However, there is no study available yet on the effect on efficacy when the gap is more than 12 weeks.
Vaccine after being infected
The Centre has so far not issued any official guideline on how long a person infected by coronavirus should wait before taking the vaccine.
However, the United States’ Centers for Disease Control and Prevention suggests waiting for 90 days from the day of getting infected, The Indian Express reported. Virologist Gagandeep Kang said that data from the United Kingdom showed that an infected person’s body could offer up to 80% protection and he/she could wait till six months before taking the shot. She said it was in line with recommendations from the World Health Organization, which said natural antibodies are likely to persist in the body until then.
Meanwhile, the recommendations from the National Technical Advisory Group on Immunisation came amid reports of shortages of vaccine from several parts of the country and the lagged dosage regimen may help in dealing with that aspect.
At least eight states have decided to float global tenders for procuring the doses as they struggle to inoculate those in the age group of 18-44, who became eligible for the shots in third phase of vaccination that rolled out on May 1. Under the new vaccination policy, states and private hospitals have the onus of procuring vaccines for those in the 18-44 age group, from the manufacturers directly. But the policy leaves only 50% of the vaccines manufactured by Bharat Biotech and Serum Institute of India to be used to inoculate nearly 60 crore beneficiaries in this age group. The remaining half of the stock is earmarked for the Centre to vaccinate priority groups.
So far, over 17.66 crore doses of the vaccine have been administered, while nearly 3.85 crore beneficiaries have received both the doses, according to government data.