A Haryana-based NGO worker, who received Covaxin as the first COVID-19 vaccine administered the Covishield vaccine as the second dose at a vaccination centre in Gurgaon. Harteerath Singh, who took to Twitter to report the authorities about the blunder claims that he had shown his vaccination certificate at the time of inoculation.

"Any leads to doctors who are experienced in such cases- would be really helpful," Singh further wrote.

The vaccination centre officials, however, claim that Singh failed to produce a vaccine certificate at the time and informed them about his previous dose only after the second dose was administered. Singh was administered Covaxin on June 8, according to his vaccination certificate.

Singh, on the other hand, denied any negligence on his part and gave a point by point answer to the vaccination centre head who blamed him for not showing the certificate.

In a response tweet, Singh wrote that the officials' claims were blatant lies and that he is educated enough to understand the difference between the two vaccine doses.

"Blatant lies by CMO- Gurgaon when they gave me second dose of CoviShield instead of Covaxin.

1. The centre had both types of vaccines.

2. I showed the certificate on the spot itself (attaching screenshot here)

3. I am educated enough to know the difference between two kinds of vaccine and won’t suddenly 'realise'

4. The doc who administered the vaccine to me clearly admits, it was a “human error” in the same article," wrote Singh.

Singh further informed that he was also kept under observation for two hours. 

Talking about any potential side effects or pain, Singh told NDTV that he is unable to feel his joints and has headaches and body pain.

Gurgaon Chief Medical Officer, Virendra Yadav, told NDTV that the matter is being investigated. 

Harteerath Singh is among those who worked day and night to help people arrange medicines, hospital beds and oxygen during the second, deadly wave of COVID-19 in India.

However, this is not the first instance of vaccine mix-up in India. In a different incident reported from Maharashtra, a 72-year-old Dattatraya Waghmare, a resident of a village in Maharashtra's Jalna district was given two different doses of COVID vaccines.

Just like Singh, the man was also given Covishield after Covaxin. The man complained of anxiety attacks with fever and skin rash.