Manas Dasgupta
NEW DELHI, June 16: The centre has denied a report in a section of the media that the government increased the gap between two doses of vaccines unilaterally last month without the scientific advice because of the shortage of vaccines in the country at that stage. The report was based on a foreign news agency which quoted three scientist members of the high-level advisory committee constituted by the government for the massive vaccination programme.
The union health minister Harsh Vardhan on Wednesday said the decision to increase the gap between two doses of the Covishield vaccine was “transparent” and was “based on scientific data.”
“India has a robust mechanism to evaluate data. It is unfortunate that such an important issue is being politicised!” the Health Minister tweeted.
This is amid concern the intervals were widened – from six-eight weeks to 12-16 – without the support of the scientific group the government said had recommended the decision with “no dissenting voice”.
Vardhan attached a statement from the government that extensively quoted Dr NK Arora, the chief of the National Technical Advisory Group on Immunisation (NTAGI), on the subject.
In the statement Dr Arora was quoted citing a study by UK health regulator Public Health England that “showed vaccine efficacy varied between 65 per cent – 88 per cent when interval is 12 weeks.”
“This was the basis on which they overcame the outbreak due to the ‘alpha’ variant… because the interval they kept was 12 weeks. We also thought that this is a good idea… scientific reasons to show that when interval is increased adenovector vaccines give better response,” he was quoted.
“The COVID Working Group took that decision with no dissenting voice…. issue was then discussed threadbare at an NTAGI meeting, again with no dissenting notes. The recommendation was that the vaccine interval has to be 12 – 16 weeks,” he was further quoted.
The foreign agency report quoted three scientists, including MD Gupte – the former Director of the government-run National Institute of Epidemiology – as saying they only discussed increasing the interval to eight-12 weeks.
“Eight to 12 weeks is something we all accepted, 12 to 16 weeks is something the government has come out with,” he said, adding, “This may alright, may not be. We have no information.”
This was echoed by his NTAGI colleague Mathew Varghese, who said the group’s recommendation was only for 8-12 weeks.
The NTAGI did not specifically discuss a 12-16 week interval, JP Muliyil, another member, added.
The news agency had also claimed that Dr Arora declined to comment on their report, but said all decisions were collective.
In mid-May the government had cited “available real-life evidences particularly from the United Kingdom” to increase the gap between the two doses of vaccines for better effectiveness. It was the second time in as many months that the gap was increased and triggered speculation that the decision was to stall criticism on account of shortage of vaccines.
A release issued by the union health ministry quoted Dr Arora having told an interviewer on Doordarshan news channel that the increased gap in inoculating “Covishield” vaccines was decided on the scientific basis of behaviour of the vaccine.
“In the last week of April, 2021, data released by Public Health England, the United Kingdom’s executive agency of the Department of Health, showed that vaccine efficacy varied between 65% – 88% when the interval is 12 weeks. This was the basis on which they overcame their epidemic outbreak due to the Alpha variant,” he noted.
This issue was discussed and with no dissenting notes, the recommendation was that the vaccine interval had to be 12 – 16 weeks. The earlier decision of four weeks was based upon the bridging trial data available then.
“Two to three days after we took the decision to increase the dosage interval, there were reports from the U.K. that a single dose of AstraZeneca vaccine gives only 33% protection and two doses give about 60% protection; discussion has been going on since mid-May whether India should revert to four or eight weeks,” Dr Arora observed. It was decided to establish a tracking platform to assess the impact of the vaccination programme.
“When the NTAGI took this decision, we also decided that India will establish a vaccine tracking platform – to assess not only the impact of the vaccination programme, but also the type of vaccine and interval between doses, and what happens when someone is fully / partially immunised. This is very important in India, since around 17 – 18 crore people have received only one dose, while around 4 crore people have received two doses,” he stated.
Dr. Arora referred to a study by PGI Chandigarh that compared the effectiveness of partial vs full immnunisation. “A PGI Chandigarh study very clearly shows that vaccine effectiveness was 75% for both partially immunized and fully immunized. 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 a CMC Vellore study were similar, he pointed out. “Few days back, another important study by CMC Vellore, Tamil Nadu, which covers most of the current epidemic wave India experienced in April and May, 2021, shows that if somebody is partially immunised, vaccine effectiveness of Covishield is 61%, and with two doses, the effectiveness is 65% – and there is very little difference, especially since there is some degree of uncertainty involved in these calculations.”
Beside the PGI and CMC Vellore studies, two other studies were coming up from two different organisations within Delhi. “And both these studies show that breakthrough infection with one dose is around 4%, and around 5% with two doses, basically hardly any difference. And the other study shows that 1.5% – 2% breakthrough infections,” he said.
Data from various sources would be integrated to assess and report on the impact of various aspects of the vaccination programme. India had a robust system for monitoring Adverse Events Following Immunisation (AEFI), he stressed.
When asked about any proposal to reduce the Covishield gap, he said a decision would 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 emphasised that ultimately, “the health and protection given to our community is paramount. This is the most important thing which drives our discussions, generation of new scientific evidence and decision-making.”
