Results have been released from 20 rounds of seroprevalence studies that have been conducted across the country by state governments to calculate the spread of Sars-CoV-2 — the virus that causes Covid-19.
On Tuesday, Chennai became the latest city to release the results of a serological survey. It showed that 21.5% of the city’s population has been exposed to Sars-CoV-2.
A look at what other serosurveys across the country have revealed about the spread of the virus:
ICMR conducted its first nationwide survey in May, while a second one is underway
WHAT THE FIRST ROUND FOUND
The first sero survey, which was conducted by Indian Council of Medical Research (ICMR) alog with National Centre for Disease Control, state health departments and the World Health Organisation (WHO) had shown pan-India prevalence of Sars-Cov-2, the virus that causes Covid-19, at 0.73%
ROUND TWO CURRENTLY UNDERWAY
ICMR is now conducting second round of a nationwide seroprevalence survey, it said on August 28
The sampling has already started for the ICMR’s second serosurvey, with many states finishing sample collection and the others in various stages of completing the process.
Who will be surveyed?
Like in the previous exercise, this survey is designed as a cross-sectional survey of adults aged 18 years or more from 21 states, wherein the districts were categorised into four strata according to the reported Covid-19 cases per million population (zero, low: 0.1-4.7, medium: 4.8-10 and high: >10).
“We have from ICMR embarked on the second national serosurvey, and it is also a work in progress, and should be completed, hopefully, by the first week of September.” - Dr Balram Bhargava, ICMR director general