ICMR, NCDC to start serosurvey to monitor COVID-19 prevalence at district level

Two government research bodies at the forefront of the fight against the coronavirus are in the process of initiating a population-based serosurvey to monitor the trend in prevalence of the infection at the district level, the Union Health Ministry said on Monday.

The Indian Council of Medical Research and the National Centre for Disease Control will collaborate with key stakeholders for the survey at 10 health facilities (6 public and 4 private).

A serosurvey involves testing of blood serum of a group of individuals to determine the presence of antibodies against that infection.

The ministry said in a document uploaded on its website that there is a need to establish systematic surveillance for SARS-CoV-2 infection in all districts of the country.

"This surveillance will be in addition to the routine testing as per current testing guidelines," it stated.

The survey will include 200 samples a week and 800 samples per month, it said.

It would test outpatient attendees (non-ILI patients) and pregnant women among the low-risk group, and health care workers among the high-risk population.

At least 100 samples per week and 400 per month of healthcare workers from selected districts would be tested.

The document stated that throat/nasal swabs will be collected for RT-PCR tests and samples would be tested in a one-time pool of 25.

"Results of this sample pooling is 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 RTPCR based testing for surveillance purpose," it said.

Data on demographic characteristics will be collected on a specifically designed standard data collection form.

The data will be analyzed locally for action using standard indicator formats. Indicators for person, place, time and trend analysis will be made. Data collation and dissemination will take place as decided jointly by ICMR and department of health and family welfare, it said.