The centre 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 that is 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 practised interval of 4-6 weeks, The Union Health Ministry said on March 22.

In a letter written to the chief secretaries of states and UTs on Monday, Union Health Secretary said the ministry has accepted the recommendations of NTAGI and NEGVAC. It has thereafter advised the states and UTs to ensure the administration of 2nd dose of Covishield to beneficiaries within this stipulated time interval of 4-8 weeks after the 1st dose", he said.

Keeping the existing scientific evidence in view, it appears that protection is enhanced if the second dose of Covishield is administered between 6 to 8 weeks, but not later than the stipulated period of eight weeks, he said. This decision of revised time interval between two doses is applicable only to Covishield and not to Covaxin vaccine, the ministry said.

The Union Health Secretary has urged states and UTs to instruct the officials concerned accordingly to undertake necessary steps to widely disseminate the message of revised dosing interval amongst programme managers, vaccinators and recipients of the Covishield vaccine and ensure adherence to the revised dosing interval, the ministry stated.