COVID-19 vaccination | Centre extended gap between doses of Covishield, not Covaxin ― here's why

While the gap between inoculations of Covishield has been extended several times, it has remained unchanged for Covaxin – the COVID-19 vaccine developed by Bharat Biotech. (Representative image)

The Centre again revised the gap between the two doses of Oxford-AstraZeneca’s Covishield – a COVID-19 vaccine manufactured by the Serum Institute of India (SII) last week.

At the beginning of the vaccination drive in January, the two doses were meant to be administered with a gap of four-six weeks. Later, the Centre revised it to four-eight weeks. Last week, it said that the doses of the vaccine are to be administered 12-16 weeks apart, following a recommendation by a government panel, saying it was a "science-based decision".

While the gap between inoculations of Covishield has been extended several times, it has remained unchanged for Covaxin – developed by Bharat Biotech.

The reason behind the extension of the gap for Covishield but not for Covaxin, has been determined by the effectiveness of the first dose of the vaccine, the Hindustan Times reported citing Indian Council of Medical Research (ICMR) chief Dr Balram Bhargava.

According to Dr Bhargava, the administration of the first dose of the Serum Institute’s vaccine results in greater immunity, which remains effective for around 12 weeks. Therefore, it has been decided to delay its second dose. However, that is not the case with Bharat Biotech’s vaccine, the report cited the ICMR head as saying.

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"It has been seen that the first dose of Covishield results in a great deal of protection, which can stay around 12 weeks. But you do not achieve a similar kind of protection after the first dose of Covaxin. It is only after both the doses of Covaxin are administered, the protection reaches the optimum level," Dr Bhargava was quoted as saying.

He termed the extension of the time range between the jabs as “evolving science”.

More than 14.58 lakh COVID-19 vaccine doses were administered in India on May 21, the Union Health Ministry's latest provisional report suggested. A total of 12.71 lakh beneficiaries received their first shot and 1.87 lakh people were given their second dose on the day.

With that, the cumulative number of COVID-19 vaccine doses administered in the country reached 19.33 crore.

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