BENGALURU: Karnataka will conduct its third Covid sero survey in another week following advice from the Covid Technical Advisory Committee (TAC), confirmed state Health Commissioner Randeep D. Though the protocol will be the same as the last two sero surveys, children will be included this time, said Dr Pradeep Banandur, head of the epidemiology department at the National Institute of Mental Health and Neurosciences (NIMHANS) and member of TAC.
A sero survey is used to estimate the prevalence of antibodies against a specific infectious pathogen as an indicator of immunity. “The protocol has been laid out and a go-ahead has been given to the procurement committee as we need reagents. This time, some portion of the population to be sampled will have received the Covid vaccination, so we have to take that bias into account. Antibodies detected may be due to natural infection or vaccination,” Randeep said. Dr Banandur, however, said that there is no need to know if the immunity is derived from vaccination or natural infection.
Antibody prevalence after second survey in Karnataka just 15.6%
“We have suggested to the government that there be no exclusion of any age group this time. All districts will be part of the survey, where RT-PCR tests will be used for detection of active infection,” he said. In the state’s second Covid sero survey, lower levels of Immunoglobulin G (IgG) seroprevalence due to antibody waning were revealed.
The IgG is the most common type of antibody found in the blood. The estimated IgG prevalence at the end of the second survey was just 15.6 per cent and was markedly lower than the estimated total infection of 27.7 per cent at the end of the first serosurvey.
However, The New Indian Express exclusively reported in November 2020 that nearly half of Karnataka’s population was infected by Covid-19 by August 2020, not just in urban areas, but in the villages too, according to a private sero survey conducted between mid-June and August.