New Delhi, Dec 14 (IANS): The Centre on Tuesday told the Delhi High Court that the appropriateness or necessity of a booster dose of Covid-19 vaccine is yet to be decided as the complete biological characteristics of the infectious disease, which impacted the country since 2020, are yet unknown.

The current priority of the National Covid-19 Vaccination Programme is to cover the entire eligible population with full vaccination and at present, there are no guidelines regarding administration of booster doses from the expert bodies, an affidavit filed by Central government's Standing Counsel Anurag Ahluwalia said.

Two expert bodies - the National Expert Group on Vaccine Administration for Covid-l9 (NEGVAC) and the National Technical Advisory Group on Immunisation (NTAGI)-- provide overall guidance and recommendations on all aspects of Covid-19 vaccination to the Ministry of Health and Family Welfare, the affidavit said, adding the two are deliberating and considering scientific evidence related to dose schedule of Covid-19 vaccines as well as the need and justification of booster doses.

It was submitted that the current knowledge about the duration of immunity offered by Covid-19 vaccines in India is limited and will clearly be known over a period of time only.

The Centre's response came after the HC had on November 25 sought it to file an affidavit on the aspects relating to the booster dose, and the timeline within which the same is proposed to be rolled out.

Stressing upon the efficacy of booster dose for those who have been fully vaccinated, the bench noted that the medical view indicates a fall of immunity against the disease after some time. This creates the need for a booster dose for people, particularly the elderly and those suffering from other diseases, it noted.