As the rate of COVID-19 infections continues to drop post the devastating second wave of the pandemic in Karnataka, the state government will soon start a sero-survey targeting children as suggested by an expert committee. The committee led by Dr Devi Shetty was formed by the government to recommend measures in preparation for the third wave of infections, which is feared to impact children more compared to the previous two waves.
Unlike tests for individual infections, the sero-survey will check for the prevalence of antibodies in the population over and above those who clinically tested positive for the virus, suggesting a more accurate picture of the extent of the infection. This, as often people who are infected with the coronavirus may not get tested due to lack of symptoms while some may get false-negative results due to technical reasons. Further, those vaccinated will also test positive for the antibody test.
Karnataka has done two sero-surveys since the onset of the pandemic but none included children. Dr Srikanth, member of the COVID-19 expert committee for the third wave, also pointed out that multiple studies have shown that naturally acquired immunity against the virus lasts for an average of three months while the same from the vaccine lasts for six months.
Dr S Sachidananda, ex-Vice-Chancellor, Rajiv Gandhi University of Health Sciences and member of multiple state-level COVID-19 expert committees until recently, said the sero-survey will focus on children to ascertain if indeed children will be more susceptible to the third wave. “Further the extent of the infections across the population will also give us a fair estimate of the vulnerability and the potential extent of the third wave,” he added.
Speaking with TNM, Dr Srikanth JT, member of the third wave committee, said, “We have recommended that a sero-survey with a sample size of 35,000 or more including different subsets of rural, urban, slum population be done at the earliest. We have asked the government to take help from statisticians to design the sample.” He explained that raw results of the survey, which can be prepared within a week’s time will give a better idea of the situation based on which decisions can be made ahead of the feared third wave.
“For interpretation of the data which comes out of the survey, we have suggested that it is done in conjunction with a wider panel of experts rather than the committee alone. We also have to be mindful that even if a child has been exposed to a certain variant, it does not guarantee immune response to newer variants of the virus,” he said.
He added, “The sero-survey will give us a better idea of the number of cases that have been missed and give us a baseline to estimate the real numbers and make adequate preparations.” He suggested the committee is also trying to collate several already available sero-surveys among children, which have already been done at a hospital level.
Dr Anand Lakshman, a public health professional and CEO Address Health, said without seroprevalence studies in children at a population level and at a sentinel site level (like pediatric hospitals) it will be hard to track infection rates rising or existing prevalence of infections. “Without this current data , we will be guesstimating needs,” he added. He pointed to a Delhi government sero-survey done in August 2020 that suggested that seroprevalence in children was at 34.7% compared to 29.1% of adults. He added, “Studies across the world have so far suggested children are half as susceptible and one-third as likely to be symptomatic.”