This is the third increase in interval for Covishield. When India started the vaccination drive in January, the recommended gap was four to six weeks. In March, the gap period was revised and extended to four to eight weeks.

The Centre on Thursday approved the gap between the first dose and the second dose of a Covid-19 vaccine Covishield based on the recommendation of expert panel. The National Technical Advisory Group on Immunisation (NTAGI) had recommended that the gap between the two doses of Covishield can be further extended to 12 to 16 weeks.

The NTAGI recommendation was accepted by the Union health ministry on Thursday.

No such changes were recommend in the intervals of Bharat Biotech's Covaxin. Experts say that Covaxin has been developed using a "dead virus, which is incapable of infecting people but still able to instruct the immune system to mount a defensive action against an infection". There is no data on whether the effectiveness increases if the gap is widened as during the trial.

This is the third increase in interval for Covishield. When India started the vaccination drive in January, the recommended gap was four to six weeks. In March, the gap period was revised and extended to four to eight weeks.

A study published in medical journal The Lancet on February 19 claimed a 26.2 per cent increase - from 55.1 per cent to 81.3 per cent - if doses were spaced 12 or more weeks apart.

NTAGI comprises of government representatives from the Department of Women and Child Development, internal finance division in Ministry of Health and Family Welfare, Department of Biotechnology, Drug Controller General of India (DCGI) along with health experts.

India started the world's largest vaccination drive on January 16 this year in a phased manner with healthcare workers (HCWs) getting inoculated first. The vaccination of frontline workers (FLWs) started from February 2.

Also Read: Defer vaccination for 6 months after recovery from Covid-19, says govt panel

The next phase of Covid-19 vaccination commenced from March 1 for those over 60 years of age and for people aged 45 and above with specified co-morbid conditions. India launched vaccination for all people aged more than 45 from April 1.

India started the world's largest vaccination drive on January 16 this year in a phased manner with healthcare workers (HCWs) getting inoculated first. The vaccination of frontline workers (FLWs) started from February 2.

Also Read: Defer vaccination for 6 months after recovery from Covid-19, says govt panel

The next phase of Covid-19 vaccination commenced from March 1 for those over 60 years of age and for people aged 45 and above with specified co-morbid conditions. India launched vaccination for all people aged more than 45 from April 1.