The results of a second serosurvey conducted in Karnataka have led to the revelation that the state is far from attaining natural immunity against Covid-19 in January this year and thus there is a need to step up vaccination coverage and laying out of rules to prevent the disease from spreading.
The second serosurvey conducted January-February this year bore results eight months later on a preprint server and found antibodies in 15.6 percent of the population and active Covid infection in just 0.5 percent.
The study of 41,228 participants across 290 healthcare facilities in all 30 districts of Karnataka was done among three groups of participants namely low, moderate, and high risk. This study found the Statewide infection fatality rate (IFR) to be 0.11 percent, and Covid-19 burden between 26.1 to 37.7 percent.
Reacting to the recent revelation, Epidemiologist and State Covid-19 Technical Advisory Committee (TAC) member Dr. Giridhar Babu took to Twitter stressed on antibody waning and noted that near-zero prevalence of active cases were found during mid-February 2021
Another TAC member Neurovirologist Dr V Ravi, a state nodal officer for genetic confirmation of SARS-CoV-2 virus, told the Deccan Chronicle that, “One should remember that this survey was done when the first wave ebbed. The people who participated in the second round were those who didn’t participate in the first round (in September last year). So, these infections are in addition found in the first survey."
He, therefore, suggested that to get the correct figure, one should add both results that come to 42.9 percent (27.3 percent prevalence found from first serosurvey + 15.6 percent from the second survey). He also attributed the occurrence of second wave of covid to these figures which meant more than half of the population was not exposed to the virus.
He pointed out that the gap between both the rounds of serosurveys was more than three months due to which antibodies waned.
As a solution, Dr Ravi noted that the state should conduct atleast 1.2 lakh vaccinations per day and sustain high levels of testing while they wait for the government clearance to do the third survey.
At present, Karnataka is witnessing a surge in cases due to a mix of alpha, and delta variants which have been picking up speed since April.