Just over 24 per cent cent population has been infected by novel coronavirus and nearly 96 per cent of them are asymptomatic cases, a second serosurvey conducted in Punjab’s 12 districts has found.
The survey involving a sample of 4,678 people was conducted among randomly selected districts and population of the state, Health Secretary Hussan Lal said. Of these, 1201 (or 24.19 per cent) tested IgG reactive, of which only 4.03 per cent were symptomatic and 95.9 per cent asymptomatic, Lal said.
The urban areas showed 30.5 per cent seroprevalence, while it was 21 per cent in the rural areas. Ludhiana, with 54.6 per cent total positivity and 71.7 per cent urban positivity was found to be the worst hit, followed by Ferozepur, Jalandhar and SAS Nagar (Mohali). Female positivity was found to be higher in both urban and rural areas.
Each district was assigned the task of completing a sample size of 400, with 200 samples each from rural and urban areas, it said.
A serosurvey involves testing the blood serum of a group of individuals for the presence of antibodies against the infection to know who has been infected in the past and has now recovered.
Last month, Chief Minister Amarinder Singh gave the go-ahead for the second serosurvey to be conducted across a larger sampling area to assess the spread of coronavirus in the state. At a virtual Covid-19 review meeting last month, the CM had agreed with health experts on the need to find the extent of spread of SARS CoV-2 outside the containment zones, in contrast with the first serosurvey that was conducted in August in five containment zones across five districts.
The first survey conducted in one containment zone each in Patiala, SAS Nagar, Ludhiana, Jalandhar and Amritsar had found 27.8 per cent seroprevalence.