The Indian Express spoke to several officials and experts at the Centre and the states and found that in state after state, serosurveys underlined that the second Covid wave was coming and yet little was done with the data or as follow-up.
Indeed, in January, when almost every state was reporting a decline in case numbers, Kerala was witnessing a surge — contributing almost half of all cases in the country. By mid- February, the confirmed cases in the state had crossed 10 lakh, second only to Maharashtra.
This “outlier” trend in Kerala was not very well understood until the state did a serosurvey in January-February in all its 14 districts. It revealed that only about 10% of the state’s population had been infected. In other words, a majority was still susceptible.
Importantly, the survey offered clues to the state’s high case count. For, Kerala had identified and tested at least one of every four infected individuals. In the country as whole, this number, estimated from a prior serosurvey, was just one in about 30.
Another insight the state gleaned from the serosurvey was that the risk of infection among those 70 years or above was significantly less, indicating that reverse quarantine – where the vulnerable are isolated – was effective.