Nearly 70% people in Karnataka were exposed to Covid-19, suggest sero-survey

The Centre has directed states to carry out sero-prevalence surveys on their own in order to find out inter-district variations to guide actions on the ground

Nearly 70 per cent of people in Karnataka were exposed to SARS-CoV-2 in the last one and half years, the Union Health Ministry said on Wednesday, directing states to carry out sero-prevalence surveys on their own in order to find out inter-district variations to guide actions on the ground.

Releasing state-wise results from Indian Council of Medical Research’s fourth sero-prevalence survey, the Union Health Secretary Rajesh Bhushan asked the states to generate district-level data on sero-prevalence, which is essential in formulating localised public health response measures.

Carried out in June-July, the fourth ICMR survey found a sero-prevalence of 67.6 per cent for the nation, which means nearly two-thirds of the Indians were exposed to the Covid-19 virus. However, there is widespread variation between the states ranging from 79 per cent in Madhya Pradesh to 44 per cent in Kerala.

Also Read — Majority in big states have Covid-19 antibodies: Survey

The exposure, however, doesn’t mean 67 per cent Indians suffered from Covid-19 infections. It only signals the silent spread of the infection among the majority of the Indians, while only a small fraction of them fell sick.

In southern India, Covid-19 specific antibodies were detected in 70 per cent of people in Andhra Pradesh, Karnataka and Tamil Nadu, 63 per cent of individuals in Telangana and 44 per cent in Kerala. In the north, it is 79 per cent in Madhya Pradesh, 76 per cent in Rajasthan and Bihar, 75 per cent in Gujarat and 71 per cent in Uttar Pradesh. Maharashtra reported a sero-prevalence of 58 per cent.

"This means a lot of cases and deaths must have gone unreported in the northern states as Kerala and Maharashtra have better case detection rate. Compared to Bihar detecting one out every 134 cases and Uttar Pradesh’s one out of 100 infections, Kerala has a detection rate of one out of every six cases and Maharashtra one out of every 12 cases,” Rijo John, a health economist and a visiting professor at the Indian Institute of Management, Kozhikode told DH.

Also Read: No room for complacency in Covid fight, absolute case numbers still high: MHA to states

ICMR’s national sero-survey was designed to capture the extent of the spread of Covid-19 infection at the national level and not to reflect the heterogeneity of sero-prevalence between districts and even between the states, the ministry said in a statement.

"The ICMR survey was conducted in 70 districts and was not a truly representative one. District specific surveys, on the other hand, would provide a much better picture. Every state should carry out such surveys,” said John.

Some of the other states with high sero-prevalence are Chhattisgarh (74.6 per cent), Uttarakhand (73 per cent), Odisha (68 per cent) and Punjab (66.5 per cent).

The ministry advised the states to conduct sero-prevalence studies in consultation with ICMR, so that such studies follow a standardised protocol and the findings can be utilised to guide objective, transparent and evidence-based public health responses to the epidemic.