Antibodies against SARSCoV-2 were found among 8 per cent of the the state’s population in a seroprevalence survey conducted in Haryana last month, with people in urban areas and districts in the National Capital Region found affected more, state Health Minister Anil Vij said on Friday.
According to the survey, Faridabad tops the list, with 25.8 per cent of people in the district having had the infection at some point, while Rohtak – at 1.1 per cent seroprevalence – was the lowest. Prevalence is more in urban areas (9.6 per cent) compared to rural areas (6.9 per cent), it reported.
The survey found seropositivity of 7.8 per cent in samples of women tested, and 8 per cent among samples of men. Prevalence was found higher among women in Bhiwani, Gurgaon, Jhajjar and Mahendragarh district, and higher among men in Hisar, Jind, Kurukshetra, Nuh, Panipat, and Yamunanagar districts.
Why seroprevalence survey is important
Due to the high proportion of asymptomatic or mild infections, data restricted to laboratory-confirmed cases do not capture the true extent of the spread or burden of SARS-CoV-2. A seroprevalence survey uses antibody tests to estimate the percentage of people in a population with antibodies against the virus. The survey helps monitor the exposure of the general population to SARS-Cov2 infection in a particular area. A small sample of people participating in the survey represents a larger population.
The sero survey was conducted by the state government in association with PGIMER, Chandigarh. In all, 18,905 samples were tested across the state’s 22 districts, Vij said.
On Friday, the Haryana Health Department reported 1,884 fresh Covid-19 cases and 19 deaths over the last 24 hours, taking the state’s total to 71,983 and death toll to 759 so far.
Stating that the sero survey was done in August, Vij, while releasing the findings, said, “It was carried out with the aim to identify penetration of Covid-19 at the community level, and to monitor its transmission trends…. It was conducted by taking 850 people from each district – from both urban and rural population. A nodal officer was designated in every district to monitor and supervise the sero survey.”
Haryana’s Additional Chief Secretary (Health) Rajeev Arora, said, “The findings will be a useful guide in designing strategies and implementation of appropriate containment measures. The sero survey is about testing a group of individuals for presence of antibodies, as it helps understand the number of people affected by the disease. The study helped us determine the burden of Covid-19 at the community level in the state, and monitor the trends of transmission of SARS-CoV-2 infection.”
ICMR/NCDC, in collaboration with key stakeholders and state health departments, had initiated a population-based sero survey in select districts across the country.
States such as Maharashtra, Delhi and Andhra Pradesh have completed the first round of the survey, and others are in the process of conducting it.
The first round’s findings for Delhi showed its seropositivity rate at 23.4 per cent, while for Mumbai it was 57 per cent in slums and 16 per cent in non-slum areas.
Arora said that serological detection of specific antibodies against SARS-CoV-2 can “better estimate the true number of infections”, and that district-wise seroprevalence surveillance is the “need of the hour”.