Some 67% of India’s population above the age of six has been exposed to Covid-19, according to the latest national sero survey.
The Indian Council of Medical Research (ICMR) surveyed 36,227 people across 21 states in June and July – and found that two out of three has antibodies.
As this still left 400 million people vulnerable to the infection, officials warned against lax Covid protocols.
India has reported more than 31 million Covid cases and 400,000 deaths so far.
Its daily case counts have been steadily falling – they are now under 40,000 a day. At the peak of devastating second wave in May, India was reporting around 380,000 cases on average daily.
But doctors and experts have warned of a third wave given the presence of new variants and reports of crowding at markets and popular tourist spots.
“The fourth sero survey shows there is a ray of hope, but there is no room for complacency. We must maintain Covid-appropriate behaviour,” ICMR chief Dr Balram Bhargava said.
Sero-prevalence means the presence of antibodies against Covid-19 in the population.
For the first time, the survey included children, between six and 17 years – and more than half of the 8,691 samples that were tested had antibodies.
The survey also included 7,252 healthcare workers – and 85% of them had antibodies.
The third sero survey showed that 21% of India’s adults had Covid antibodies.
Click here to see the BBC interactive