Sero-survey will be conducted in December and March again

Bengaluru: Health and Medical Education Minister Dr. K. Sudhakar said that sero-survey has revealed that around 16 per cent of the State has developed antibodies against COVID-19 virus. Out of 7.07 crore estimated population of Karnataka, the study estimated that 1.93 crore (27.3 per cent) of the people are either currently infected or already had the infection in the past.

He was sharing details of the sero-survey done by various agencies from Sept. 3 to 16 at all 30 districts in Karnataka, at a news conference here yesterday. He said the survey included the proportion of people who had COVID-19 infection recently and those currently having active SARS-CoV-2 infection. The sampled population surveyed were all adults aged 18 years and above.  It was held in three groups — Low-risk group, moderate-risk group and high risk. The study used Rapid Antigen Test (RAT) and RT-PCR for the diagnosis of acute infection. At the same time, serum testing for IgG antibodies was conducted to know the protection offered by the immune response. The standard ICMR protocols were used, and ICMR approved laboratory network in the State was utilised.

The Minister said of the 16,585 persons surveyed covering the three risk categories, the analysis was done on results for 15,624 individuals whose RAT plus RT-PCR and COVID Kavach ELISA antibody test results were matched in the line list. The survey revealed that, 16.4 per cent of the people were infected in the past and found to have antibodies against Covid-19 in the surveyed population.

Dr. Sudhakar said districts with high cases infections ratio (more than 40) such as Vijayapura, Belagavi, Chitradurga, Tumakuru, Raichur, Ramanagar, Haveri, Chamarajanagar, Bidar, Davangere, Yadgir, Kalaburagi, Kolar, Mandya, Chikmagalur, Ballari, Bengaluru Rural and Hassan need to improve detection of cases actively through syndromic approach, improve testing, and ensure other public health actions are implemented efficiently. Likewise, districts with a low case to infection ratio such as BBMP Bommanahalli, BBMP East, BBMP West, BBMP South and Mysuru suggest that the strategy employed for testing is reasonable and can be replicated in other districts.

Highlights of survey

• The Infection Fatality Rate (IFR) due to COVID-19 in Karnataka is 0.05 per cent. 

• The districts with a high infection fatality rate suggest that clinical care needs to be improved in these places. The present IFR is likely an underestimate. 

• The State is passing through different stages of COVID-19 pandemic in different districts. The surge in cases is yet to occur in the districts with the lowest estimated prevalence of COVID-19 (Dharwad, Gadag, Chikkaballapur, Bagalkot, and BBMP Mahadevapura).

• The study recommends establishing the district-level facility-based sentinel sero-surveillance to monitor the trend of infection in the long-term systematically. This can inform local decision-making at the district level to mount necessary public health response towards COVID-19 epidemic in Karnataka.