2nd Sero Survey report: Urban slum & non-slum areas have higher prevalence of Corona infection.

Second sero-survey findings were released on September 29, 2020 by the Indian Council for Medical research (ICMR).

Key Findings

  • 6.6% of over 29 thousand people, aged 10 and above, surveyed from 17th August to 22nd September.
  • They showed evidence of past exposure to COVID-19.
  • 7.1% of the adult population, aged 18 and above, also showed evidence of past exposure to the virus.
  • Report says that, 1 in 15 individuals aged 10 years and above were estimated to be exposed to SARS-CoV2 by August.
  • Report shows that a considerable population is still susceptible to COVID-19.
  • As per the report, containment and behavioral change at the population level have effectively checked the potential spread of SARS-CoV2.
  • As per the report, risk in urban slums was twice than that in non-slum urban areas and four times the risk in rural areas.
  • The  second sero-survey was conducted in the same 700 villages and wards from 70 districts from 21 states as surveyed during the first survey but on different households and individuals.

Sero- Survey

Sero-survey tests the blood serum of a group of individuals to determine the presence of antibodies against that infection in them. People from different zones in a district are randomly tested for COVID-19 to check if they have developed antibodies against the infection even though they are asymptomatic or show mild symptoms. The survey involves collection of venous blood samples from random individuals in each selected district, divided into low risk and high-risk groups.

How does it survey?

While conducting the survey, Throat and nasal swabs are collected for RT-PCR tests, blood samples are collected for detecting Immunoglobulin G (IgG) antibodies for ELISA testing. Later, IgG ELISA-based testing of serum samples replaces RT-PCR based testing for surveillance purpose. After the survey, Data on demographic characteristics are collected on a specifically designed standard data collection form. The data are then analyzed locally for action using standard indicator formats.


Thus, the survey evaluates the trend of covid1-19 and establish systematic surveillance for SARS-CoV-2 infection in all districts, to determine the burden of infection at the community level, to monitor the transmission trends and help generate evidence on role of asymptomatic and mild infections in transmission and to Check for community transmission in any part of the country. The ICMR in the second sero survey report said that a large proportion of the population is still susceptible to the virus which can only be  prevented by adhering to the 5T strategy — test, track, trace, treat, technology.