India’s vaccination expert group is reviewing the decision to delay the second doses of Covishield, a top government expert said on Friday, as new scientific evidence from other countries suggest a single dose may not be adequately protective against the Delta variant of the coronavirus that has swept across the country.
Vaccine efficacy rates plummeted to under 35% in people who had only their first dose when exposed to the variant, data from the UK showed last month, prompting many experts to urge the government to reverse its decision to make a mandatory 12-week gap between doses. The latest among these was by Dr K Srinath Reddy, president, Public Health Foundation of India.
“His suggestion has been made based on data in the context of mutations in the virus; he has quoted two-three quality studies and suggested the interval should be reduced again to 8 weeks as was practised earlier. Let it be examined by our NTAGI (National Technical Advisory Group on Immunisation in India). It is a process. Even United Kingdom must have changed it after reviewing the data by scientific committees and experts,” said Dr VK Paul, member, Niti Aayog.
“Earlier they (UK officials) were giving it at 12 weeks and we were giving the second dose at a shorter interval because our experts felt it wasn’t safe to increase the interval. The decisions are made based on scientific evidences,” said Paul.
Serum Institute of India (SII) locally manufacturers Oxford-AstraZeneca Covid-19 AZD1222 vaccine under the brand name Covishield. The vaccine was tested using a four week prime-boost regimen but real world data from UK showed it led to a better protection when the second dose was delayed by 8-12 weeks.
“We will assign the responsibility to our scientific forum created in the country for the purpose. I am sure they are already addressing the issue, and will examine it keeping in mind the Indian context; the Indian disease pattern and the presence of variants circulating here. They need to take a comprehensive view and they will. We will abide by the decision made by the experts in this regard. Having said that, there is no need to panic, and switch rules overnight; these decisions must be taken carefully,” Paul added.
Experts said the four weeks is ideal in a pandemic situation to administer the second dose. “In the middle of the pandemic, postponing the second dose is not logical. For a vaccine like Covishield, 4 weeks gap is ideal, and if there is no hurry then for getting optimal immunity, 12 weeks’ time is good. However, part of the problem was short supply of vaccines which is why the gap was increased in the first place,” said Jacob John, former head, department of virology, Christian Medical College, Vellore, Tamil Nadu.
Earlier this week, the centre took a decision on reducing the period for a certain category of people who have to travel abroad either for studies or employment opportunities, and those who are part of the Indian contingent for Tokyo Olympic.
“In case of Covishield, we decreased the length of the period based on existing evidence for those who have taken their first dose and need to travel for specified reasons as the modifications will help them complete their vaccine dosage,” said Lav Agarwal, joint secretary, Union health ministry.
The vaccination process is picking pace in the country, said Paul, while adding that it was set to improve further in coming weeks with vaccine supplies increasing.
“It is obvious that as compared to the previous month, this month there were more vaccine doses available for use, and it will increase further. The process will further streamline under the Centre-state collaboration, especially vaccine procurement and distribution. Our request to people is make effort and take both the doses on time, particularly for health care and front line workers, and beneficiaries above 45 years of age.