Rethink in India as UK cuts Covid-19 vaccine gap again
Government experts handling India’s coronavirus vaccination strategy have held meetings and are considering slashing the gap between the two doses of Covishield, at least for vulnerable groups, as more evidence poured in of the second shots being crucial for adequate protection from infection and hospitalisation arising from the Delta variant of the Sars-CoV-2 virus.
On May 13, India widened the gap for second doses from a minimum of six to 12 weeks for people who get the Covishield vaccine, citing better efficacy data from the UK. But, three days later, the UK itself reduced the gap to eight weeks from 12 for people over the age of 50, citing the more serious threat from the Delta variant which has become the predominant strain of the virus in the UK.
On Monday, UK released fresh data showing protection from hospitalisation was 92% for people who had both doses of the Oxford-AstraZeneca vaccine (Covishield is the made-in-India version of the dose). Those who had just one dose showed a much lower efficacy against hospitalisation at 71%. The same day, the country also reduced the gap between doses for those over the age of 40.
A number of experts in India have now urged the government to do the same; Delta is also believed to be the dominant strain here too.
“The 8 weeks gap is being considered in the technical groups. Once they come to a view, the matter will come to NEGVAC (the national expert group on vaccine administration for Covid-19) ,” said a top Indian government official familiar with the development, who asked not to be named.
In a study of 14,019 symptomatic Delta variant infections, including 166 who were hospitalised, Public Health England reported vaccine efficacy against symptomatic disease fell to 30% if only one dose of Oxford-AstraZeneca vaccine was given, compared to 67% when both shots were administered.
In the case of the Pfizer-BioNTech vaccine, the comparable numbers were 36% and 88%. These numbers are similar to findings last month, and have been the basis for the Boris Johnson government reducing the gap between the doses and delaying a planned lifting of remaining Covid-19 curbs (the current extension is till July 19)
In India, experts said they were looking at such findings and more. “While we are open to reviewing the gap, it’s a misconception that we blindly follow the West. The truth is we are more focused on looking at the data being generated within the country to make important vaccine-related decisions. We followed the four-week interval in India when UK was following the 12-week gap, so we may be looking at the evidence coming from the West, but our decisions pivot around the data that will tell us what’s best for our people. India data is crucial for us and we are closely watching it,” said Dr NK Arora, chairman, Covid working group on vaccines.
He added: “We already have results of two studies before us from north and south India— one from PGI Chandigarh and another from CMC Vellore— that clearly tells us that irrespective of the Covishield vaccine dose interval, people getting a single dose or both the doses are having similar protection against the Delta variant (B.1.617.2) and Alpha variant (B.1.1.7).”
News agency Reuters quoted three experts who were part of the technical group known as National Technical Advisory Group on Immunisation (NTAGI) as saying that they recommendation was to extend the gap between Covishield doses to 8-12 weeks. ”Eight to 12 weeks is something we all accepted, 12 to 16 weeks is something the government has come out with,” the Reuters report quoted MG Gupte, a former director of the state-run National Institute of Epidemiology, as saying.
This was echoed by his NTAGI colleague Mathew Varghese, who said the group’s recommendation was only for 8-12 weeks, the report added. A third member, JP Muliyil, said there had been discussions within the NTAGI on increasing the vaccine dosage interval but that the body had not recommended 12-16 weeks.
“That specific number was not quoted,” Reuters quoted him as saying.
In a statement later on Tuesday, Arora said there was no dissent within the NTAGI.
Arora also said results of at least three to four more studies are expected, and the expert panel will review these in detail before taking a decision. “Interval debate has to be seen in a contextual manner based on responses we are seeing in our country as adeno-vectored vaccines behave differently in different settings and we have to make decisions based on how they behave in our population,” he added.
But other experts said the data from UK should be taken into account in India.
“These data are what need to be considered for decision-making for India,” said Dr Gagandeep Kang, physician-scientist, Christian Medical College, Vellore, Tamil Nadu, in a tweet linking to the PHE report.
Another top government expert confirmed the variant prevalent now is more dangerous, and said further mutations are being studied.
“The virus in circulation is far cleverer than what we saw in 2020; therefore we need to be more alert while dealing with it as RNA viruses are particularly predisposed to errors in their replication that leads to the virus acquiring a new character to an extent.
“The intense second wave was a result of the highly transmissible Delta variant, B.1.617.2, that was circulating in India. On similar lines an additional mutation has been detected that has been sent to the global data system and is called delta plus variant,” said VK Paul, member (health), Niti Aayog, at the government’s routine press briefing on Covid-19.
(With Reuters inputs)