The Centre on Monday revised the time window within which the 2nd dose of Covishield vaccine can be taken, asking all states and Union Territories to administer it between 4-8 weeks instead of 4-6 weeks.

"In view of the emerging scientific evidence, the interval between two doses of a specific COVID-19 vaccine i e. COVISHIELD , has been revisited by National Technical Advisory Group on Immunisation (NTAGI) and subsequently by NEGVAC in its 20th meeting during which the recommendation has been revised to provide 2nd dose of COVISHIELD at 4-8 weeks' interval after 1st dose instead of earlier practiced interval of 4-6 weeks," The Union Health Ministry Monday said.