A doctor attached to a civic-run hospital who had received the first dose of coronavirus vaccine contracted the viral infection some days ago and has now recovered, a BMC official said on February 19.

An expert from the Maharashtra government's task force said this was not unusual as a recipient of COVID-19 vaccine does not develop immunity immediately. The 46-year-old doctor working at BYL Nair hospital tested positive for the virus nine days after he received the first dose of Covishield vaccine, said an official of the Brihanmumbai Municipal Corporation.

Dr Ramesh Bharmal, dean of the hospital, told PTI that the doctor tested positive last week but now he has recovered from the infection and is expected to join work soon. Dr Om Shrivastav, an infectious diseases expert who is also a member of the state government's task force on coronavirus, said a person can be infected with coronavirus even after getting a vaccine dose.

Immunity for the virus starts developing two weeks after getting the first jab and for optimum immunity, a booster (second) dose is necessary, Dr Shrivastav said. "Whenever you get a booster dose, that is the time when the immunity is going to be at its peak. Whether it will be 100 per cent or not it is difficult to say. It's too early. "But you will get the best immunity after the second dose," he added.

As of February 18, around 1.40 lakh healthcare workers and frontline workers had been administrated COVID-19 vaccine in Mumbai. A senior BMC official said it takes at least 45 days after the second dose to get full immunity, and therefore people should follow safety norms even after receiving the shots.