The gap between the second dose of Covid -19 vaccine and the third, which is being called a "precaution dose", is likely to be nine to 12 months, official sources said on Sunday.

The nitty-gritty of the gaps for the vaccines currently being used in India's inoculation programme Covishield and Covaxin is being worked out, and a final decision over this will be taken soon, they said.

Prime Minister Narendra Modi, in a televised address to the nation on Saturday night, announced that vaccination against Covid -19 for children between 15-18 years will start from January 3, while "precaution dose" for healthcare and frontline workers would be administered from January 10.

The decisions came amid rising Covid cases linked to the omicron variant of the virus.

Modi said the precaution dose will also be available for citizens above 60 years of age and with comorbidities on the advice of their doctor from January 10 next year as well.

The precaution dose denotes a third dose of the vaccine for the fully vaccinated but Modi refrained from using the term "booster dose", as it is generally referred.

"The gap between the second and the precautionary dose of Covid vaccine is likely to be nine to 12 months with the immunisation division and the National Technical Advisory Group on Immunisation (NTAGI) discussing on these lines," a source said.

More than 61 per cent of India's adult population has received both doses of the vaccine. Similarly, about 90 per cent of the adult population has received the first dose.

With the administration of 32,90,766 vaccine doses in the last 24 hours, the cumulative Covid -19 vaccine doses administered in the country has exceeded 141.37 crore, as per provisional reports till 7 am.

PTI