The Ministry of Health and Family Welfare on Monday decided to conduct a population-based sero-survey in select districts across the country, saying there is a need to establish systematic surveillance for SARS-CoV-2 infections across the country.
The Ministry said this surveillance will be in addition to the routine testing, as per current guidelines.
"Besides facility-based surveillance, ICMR/NCDC in collaboration with key stakeholders and state health departments is initiating a population-based sero-survey in selected districts representing case detection across the country," the ministry said.
A sero-survey involves testing of blood serum of a group of individuals to monitor trends in the prevalence of novel coronavirus or SARS-COV-2 infection at the district level. The surveillance unit will consist of 10 health facilities (including 6 public and 4 private) from each district. Among the low-risk population, outpatient attendees (non-ILI patients) and pregnant women will be tested while among the high-risk population healthcare workers will be surveyed.
At least 100 samples per week and 400 per month from selected districts among the high- risk population, 50 samples per week and 200 per month of outpatient attendees (Non-ILI patients), as well as pregnant women will be collected.
The survey will include a total of 200 samples per week and 800 samples per month for the purpose.
Throat and nasal swabs will be collected for RT-PCR tests and samples tested in a one time pool of 25.
However, the ministry said, results of this sample pooling are only for surveillance purposes. It should not be used for diagnosis of individual patients.
"In addition to throat/nasal swabs, blood samples should be collected for detecting IgG antibodies for ELISA testing. In subsequent rounds, IgG ELISA-based testing of serum samples will replace RT-PCR based testing for surveillance purposes," said the ministry.
In addition, the ministry said the data will be analyzed locally for action using standard indicator formats. Indicators for person, place, time and trend analysis will be made.
The method will be jointly implemented across the country by the district and state health administration, Integrated Disease Surveillance Programme, National Centre for Disease Control, Indian Council of Medical Research institutes, community medicine departments of medical colleges and public health institutes, said the ministry.
( With inputs from IANS )