BENGALURU: The Union Government’s decision to extend the gap between two doses of the Covishield vaccine to 12-16 weeks from the existing 4-8 weeks, following the recommendation of the National Technical Advisory Group on Immunization (NTAGI), has sparked off a debate amongst the medical fraternity, public health experts and also those who are closely following the vaccine availability and shortage in the country.
Many of them felt that the decision, coming at a time when several states are battling a shortage of vaccines, may be viewed as the government inability to tide over the vaccine shortage and create further confusion among people who have already taken the first dose of vaccine and are planning to get the second dose after a gap of four weeks.
“As a vaccinologist I know about vaccine responses. The first dose is a sensitising one and it can be boosted anytime within one year. But what I fail to understand is why this shortage? Didn’t the government order enough vaccines earlier? Are they depending on the manufacturers? There has definitely been a mismatch in the government’s planning of the vaccine administration,” said Dr John Jacob, renowned virologist and former professor at CMC Vellore.
The experts, however, agree that there have been studies published in medical journals like The Lancet and real-life evidence, particularly from the UK, showing that the efficacy of the vaccine is higher when there is a gap of 90 days. A senior doctor said, “I agree that some countries like the UK and Canada have done this, but why is it that our government didn’t think of it earlier? Just a few days ago, they were speaking about the importance of taking the second dose.”
“Also, the Karnataka government has suspended vaccination for 18-44 year age group, claiming that all available vaccines will be used to inoculate those waiting for the second dose. Aren’t these SOPs from the government confusing,” asked the senior doctor.
Explaining that evidence from other countries that a delayed second dose, up to 12 weeks and beyond, is beneficial and showed higher efficacy was available since January, Dr Giridhara R Babu, a member of the state Technical Advisory Committee, pointed out that the National Expert Group on Vaccine Administration for Covid did not agree to it earlier. “I am happy that they have agreed now. It is a decision based on evidence,” he said.
Dr V Ravi, also part of the Mission Covid Suraksha -- set up by the Union Health Ministry to accelerate development of vaccines, explained that an individual’s immune system retains memory from three months to six months. “During this time, the maximum interval can be stretched and we have seen studies showing that even after one dose of vaccine, we can get 40 to 50 per cent protection and the severity of the infection will definitely be less,” he pointed out.
But the panel’s suggestion of Covid-recovered patients having to wait for six months was questioned by many. Dr Ravi said that for such patients, eight weeks should be the ideal time to take the jab. Six months may be too much and there could be a reinfection, he explained.Some doctors suggested that recovered patients can get an antibody test on the spike protein and decide when to take the vaccine. A senior doctor from a private hospital asked, “What if there is a new variant and immunity wanes.”