84-Days Gap Give Best Protection: Centre To Court On Covishield

A few days ago, Kochi’s Kitex Garments Ltd filed a writ petition in the court, urging the government to allow the company to administer the second dose of Covishield vaccine to its workers before the completion of the 84-day gap. The central government said in a counter-affidavit filed in the Kerala High Court that the duration of 84 days between first and second doses of the Covishield COVID-19 vaccine gives the best protection against the coronavirus.

After the first dose, there are both protective and blocking antibodies against the S protein produced. And if you get the next shot way sooner, the blocking antibody neutralizes the second dose antigen. This causes a decrease to even no effect of the second dose. Thereby only the first dose is there and the expected heightened immune response against COVID is absent.

The Centre said that the gap was built on scientific and epidemiological evidence under World Health Organization (WHO) guidelines, and global best practices. The interval between the two doses of Covisheild had undergone a series of revisions on the basis of available and emerging scientific evidence, it said. Widening of Covishield dosage intervals has been linked to increased efficacy.

Centre in the affidavit said, “Based on the recommendations by NEGVAC, the schedule of the Covishield vaccine under the National Covid-19 Vaccination Programme is to administer the second dose at 12-16 weeks interval after administration of the first dose. This is based on the technical opinion that the duration of 84 days between 1st and 2nd doses of Covishield is providing the best protection against COVID-19.”

It further added that the second dose before the prescribed time period of 12-16 weeks was decided to provide full vaccination coverage and facilitate international travel for genuine reasons. The immunity provided by two doses of the Covishield vaccine with intervals less than 12-16 weeks would be better than partial vaccination.

“‘The decision to increase the Dose interval of the Covishield vaccine was based on scientific evidence and expert opinion as per available efficacy data,” it further said.