The Fourth National Sero Survey has delivered what may well be the best news on Covid yet: two-thirds of Indians have antibodies to SARS-CoV-2. These Indians have some immunity, therefore, to the virus. That can’t be bad.
Happily, the Covid vaccines have significantly raised the antibody prevalence in those who have taken them.
The bad news is that an estimated 40 crore Indians — more than the population of US and Canada put together — have not yet developed the antibodies that an infection results in, and remain vulnerable.
There is no reason to let our guard down, however, for mutations may cause reinfections and antibodies don’t last forever.