Covishield vaccine: India will revisit dosage interval based on emerging data

NEW DELHI, 16 Jun: India will revisit the dosage interval for Covishield vaccine and take appropriate action based on emerging data, NK Arora, the chairperson of the working group of immunization advisory body NTAGI, said.

Describing Covid and the vaccination situation as “very dynamic,” he said in a statement that the emerging evidence and reports regarding efficacy of partial versus full immunization are also under consideration.

On the decision to increase the gap between two doses of Covishield from four-six weeks to 12-16 weeks, he said the move was based on scientific decision and there was no dissenting voice among the National Technical Advisory Group on Immunization (NTAGI) members.

“Covid-19 and the vaccination are very dynamic. Tomorrow, if the vaccine platform tells us that a narrower interval is better for our people, even if the benefit is 5-10 percent, the committee will take the decision on the basis of merit and its wisdom. On the other hand, if it turns out that the current decision is fine, we will continue with it,” Arora said.

The decision to increase the gap lay in the fundamental scientific reason regarding behaviour of adenovector vaccines, a union health ministry statement quoted him as telling DD News.

On why the NTAGI did not increase the gap earlier to 12 weeks, he said, “We decided we should wait for ground-level data from the UK (the other biggest user of AstraZeneca vaccine).”

He also said that there were other examples like Canada, Sri Lanka and a few other countries which are using 12-16 weeks interval for AstraZeneca vaccine which is the same as Covishield vaccine, the statement said.

On the protection from single-dose versus two doses, Arora explained how emerging evidence and reports regarding efficacy of partial versus full immunization were being considered by the NTAGI.

“Two-three days after we took the decision to increase the dosage interval, there were reports from UK that single dose of AstraZeneca vaccine gives only 33 percent protection and two doses give about 60 percent protection; discussion has been going on since mid-May whether India should revert to four or eight weeks,” he said.

He also said that it was decided to establish a tracking platform to assess the impact of the vaccination programme. (PTI)