Hyderabad: About 12.2 per cent of Telangana’s roughly 3.5 crore population, or 42.70 lakh people, was exposed to the novel coronavirus until August, a sero survey report by Indian Council of Medical Research (ICMR)-National Institute of Nutrition (NIN) has showed.
The sero prevalence in the state rose by 20 times between May and August, according to the NIN report released Thursday. About 80 per cent of the people, found to have antibodies, were asymptomatic, the NIN scientists said.
“The same survey in May yielded very low results — that is also because there was lockdown back then, movement was less. But, the survey in August showed that the sero prevalence increased by 20 times,” Dr Avula Laxmaiah, scientist G and ICMR Nodal Officer, NIN, told ThePrint.
The latest report is from the second phase of the survey, conducted in the last week of August, done in three districts — Jangaon, Nalgonda and Kamareddy.
The baseline survey (first phase) was conducted in mid-May in the same districts. The compilation of both surveys showed exposure to 12.2 per cent of the population.
The study was carried out by NIN in association with the Ministry of Health and Family Welfare, Government of Telangana.
In the new phase, about 1,309 samples were tested in the three districts — 454 people in Jangaon, 433 in Kamareddy and 422 in Nalgonda.
According to the report, the highest sero prevalence was in Jangaon where 18.2 per cent of the tested population had IgG antibodies, compared to 0.5 per cent shown in May.
Next was Nalgonda district where 11.1 per cent populace developed IgG antibodies, much over 0.25 per cent in May. In Kamareddy, 6.9 per cent population developed IgG antibodies, as against 0.9 per cent earlier.
Sero surveys are meant to identify the level of exposure a population has to a disease.
Since the majority of Covid-19 cases are believed to be asymptomatic, the exercise helps yield a truer picture of the coronavirus prevalence by also taking into account people who may have recovered from the disease without even realising they had it.
As of Thursday, Telangana has reported a total of 1,95,609 Covid cases and 1,145 deaths, according to the state health bulletin. The fatality rate in the state was 0.58 per cent compared to the national average of 1.6 per cent.
The Greater Hyderabad Municipal Corporation limits still has the highest number of cases reported in the state.
What the scientists say
The three districts in Telangana were shortlisted based on ICMR’s four categories according to the incidence of reported Covid cases per million population (zero, low=0.1-<5, medium=5-10, high=>10).
About 10 villages/wards were selected in each district and from each selected village/ward, about 16 households were selected randomly for the study, according to the report.
“Although the parameters to decide for the entire state are different, but we can confidently say that the Covid exposure in the state is at least 12.2 percent and not below it. Another factor also taken into account was where RT-PCR tests conducted were very low,” Laxmaiah said.
The report also highlighted that the virus is spreading at a slow pace, which could be because of appropriate measures.
However, a large number of people are still susceptible to SARS-CoV2 infection, hence all appropriate personal protection measures like wearing of mask, personal hygiene and social distancing may be continued, the NIN report said.
“It is also a good thing if more people develop antibodies and are asymptomatic, this would mean there could be a possibility of herd immunity,” Laxmaiah said.
A proposal to conduct a survey in Hyderabad is also underway, subjected to approval. The institution plans to conduct another round of survey with four districts towards the end of this month.