One Covid patient in Karnataka was spreading the infection to around 12 others in January this year, the state’s serosurvey reports.
The findings of the second state serosurvey pertain to the beginning of the year (2021), but the data might help epidemiologists to chart out the future course of action amid the threat of a third wave.
Belagavi along with other districts Chamarajanagar, Mandya, Kodagu, Bagalkot Vijayapura, Ramanagara, Mysuru, Chitradurga reported a high transmission ratio.
The seroprevalence of Immunoglobulin G (IgG) antibodies against the novel coronavirus shows that 15.6 per cent of people in Karnataka have been exposed to covid.
Prevalence in is Belagavi 19.4 % while Mysuru saw 33.6% Bengaluru 18.7%.
cases-to-infection ratio (CIR) ratio higher in Belagavi
In the second round of a statewide sero survey in Karnataka conducted from 25 January to 18 February, before the second wave struck, the seroprevalence was found to be only at 15.6 per cent, which means that one in six people in the state had Covid-19 antibodies.
|Samples||%-IgG against SARS-CoV2||%-Active Infection of COVID-19||%-Prevalence of COVID-19|
|1110||19.4 (14.9–23.9)||0 (0–1.9)||19.4 (14.5–24.2)|
|Cases up to 18 February 2021||Estimated Infection||CIR – cases-to-infection ratio||IFR – infection fatality rate|
|26823||1038815||1 : 39||0.03%|
The low seroprevalence was due to antibody waning, a longitudinal substudy confirmed.
Before the second wave struck, at least 1 in 6 people had Covid antibodies as the second serosurvey has found 15.6 per cent seroprevalence in the state.
The study finds a near-0 prevalence of active cases during mid-February 2021, just before the second wave struck the state and the country.
The subsequent surge in Covid cases in Karnataka in April was due to a “mix of alpha, delta, and a huge susceptible population”, Dr Giridhara R Babu, state advisory committee member, said.