Haryana Health Minister Anil Vij tweeted on Saturday that he tested positive for Covid-19, days after being administered with a shot of Covaxin. He has been admitted to the Civil Hospital, Ambala Cantt, he said.

"I have been tested Corona positive. I am admitted in Civil Hospital Ambala Cantt. All those who have come in close contact to me are advised to get themselves tested for corona (sic)," the 67-year-old, who is also the state home minister, tweeted on Saturday.

Vij had volunteered to be the first person to receive a dose of the Covaxin during its third phase of human trials, which began in Haryana on November 20.

The Union health ministry, however, said Covaxin is a two-dose anti-coronavirus vaccine and Vij had received just one.

“The antibodies against the infection build up in a human being only after a specific number of days pass after the second dose of the vaccine is taken. This is a two-dose vaccine. The minister in question has taken only one dose of the vaccine,” it said.

The minister, too, said antibodies start to develop after administration of the second dose, which is given 28 days after the first shot, and there is no protection during this period.

“I was told that antibodies start to develop after the second dose, which is administered after 28 days of getting the first shot. And full antibodies are developed 14 days after the second dose is given. So, the complete cycle takes 42 days. In between there is no protection,” he told PTI.

Covaxin is being indigenously developed by Bharat Biotech, which has collaborated with the Indian Council of Medical Research (ICMR).

In Bengal, urban development minister Firhad Hakim became the first volunteer to be administered with a dose of Covaxin.

Earlier, the vaccine makers said that the Phase III trials of Covaxin will involve 26,000 volunteers across 25 centres in India, making it the largest clinical trial conducted for a Covid-19 vaccine in the country.