India needs to shorten Covishield dose gap: Health experts

The government should reduce the gap between the two doses of Covid-19 vaccine Covishield to ensure a high immune response in the recipients, health experts told ET.

In May, the health ministry had announced that the gap between the two doses of Covishield — being administered in its nationwide vaccination drive — was being increased to 12 to 16 weeks from six to eight weeks after examining real-life evidence from the UK.

The Oxford-AstraZeneca vaccine is being produced in India by Serum Institute of India (SII).


“The current gap of 12 to 16 weeks has two problems: first, it leaves people with one dose exposed for that much time to the risk of severe Covid with the delta variant, and second, it promotes the development of further mutations and new variants,” said Arvinder Soin, a surgeon and leading liver transplant specialist at Medanta Medicity.

“That would defeat the very purpose of vaccination for individuals and for society.”

According to the experts cited earlier, an interval of four to eight weeks between two doses of Covishield is best for India.

“Based on the updated evidence, an interval of 4-8 weeks is best for eliciting maximum protection, especially to the vulnerable. This spacing is effective against the existing and emerging delta variant,” said Giridhara Babu, a senior epidemiologist.

“Therefore, it is time to revisit and reduce the dosing interval.”

Amid the concern over the inter-dose gap, health minister Harsh Vardhan wrote on Twitter that the decision to recommend a gap of 12-16 weeks between two doses of Covishield was taken in a transparent manner based on scientific data.

Experts believe that with the UK reducing the Covishield dose gap to eight weeks, it’s time for India to follow suit.

“There is clear data from the UK showing that the Delta variant is very likely to escape the protective effect of a single dose of the vaccine, while two doses of Covishield afford excellent protection against hospitalisation (even with the Delta variant),” Soin said.

Recently, Anthony Fauci, the top medical advisor to the United States president, had said that extending the interval between vaccine doses could leave people vulnerable to infection by one of the Covid-19 variants in circulation.