Gap between jabs stirs row again
Centre says decision to increase gap was ‘transparent and backed by scientific data’
India on Wednesday reported 62,224 new cases of Covid-19 and 2,542 deaths. Country’s active caseload for the first time in 70 days came down below 9 lakh. The Recovery Rate has increased to 95.80 per cent while daily positivity rate stands at 3.22%. The positivity rate has been less than 5% for nine consecutive days. With the pace of vaccination picking up, the Centre hopes to check the daily cases and blunt the possible third wave.
However, a controversy has re-erupted over the gap between two doses of Covishield vaccine. The Centre had increased the gap between the two doses for Covishield from 8-12 weeks to 12-14 weeks in
May raising questions if that was done based on scientific evidence or due to shortage of the vaccines. The doses of the vaccines remain unchanged now even after the United Kingdom, which was quoted by Central government officials as an example, has decided to reduce the gap.
Union health minister Dr Harsh Vardhan on Wednesday clarified that the decision to increase the gap between the two doses was ‘transparent and backed by scientific data’. The clarification came after some members of the National Technical Advisory Group on Immunisation (NTAGI) said they had recommended only 8-12 weeks but the government on its own came out with a 12 to 16 weeks gap. It was initially
THE CLARIFICATION came after some members of the NTAGI said they had recommended only 8-12 weeks but the government on its own came out with 12 to 16 weeks gap.
ON ANY fresh proposal to reduce Covishield dosage gap, Dr Arora said decision will be taken scientifically, giving paramount importance to the health.
4-6 weeks.
Chairman of NTAGI Dr N.K. Arora explained that the decision to increase the gap between two Covishield doses from 4-6 weeks to 12-16 weeks lay in the fundamental scientific reason regarding behaviour of adenovector vaccines.
“In the last week of April
2021 the data released by Public Health England, United Kingdom’s executive agency of the Department of Health, showed that vaccine efficacy varied between 65%
and 88% when interval is
12 weeks. This was the basis on which they overcame their epidemic outbreak due to the Alpha variant. The UK was able to come out of it because the interval they kept was
12 weeks. We also thought that this is a good idea, since there are fundamental scientific reasons to show that when interval is increased, adenovector vaccines give better response. Hence, the decision was taken on May 13, to increase the interval to
12-16 weeks. This also gives flexibility to the community, since everyone cannot come at precisely
12 weeks or so,” said Dr Arora.
Dr Arora said that the earlier decision of four weeks was based upon the bridging trial data available then. He referred to studies by PGI Chandigarh and CMC Vellore which compared effectiveness of partial versus full immunisation. “A PGI Chandigarh study very clearly shows that vaccine effectiveness was
75% for both partially immunised and fully immunised. So at least in the short run, effectiveness was similar whether you are partially or fully vaccinated. This was in relation to the Alpha variant which had swept Punjab, Northern India and came to Delhi. This also meant that even if you received only one dose, still you are protected.” Results from the CMC Vellore study were similar.
On any fresh proposal to reduce Covishield dosage gap, Dr Arora said the decision will be taken scientifically, giving paramount importance to the health and protection of the community. “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%, 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,” he added.