BENGALURU: A sero survey conducted in DJ Halli, a densely populated, slum-like locality in east Bengaluru, in early September suggested that 58 per cent of the residents had been exposed to coronavirus.
An estimated 1 lakh people live in the 1.5-sqkm locality, one of the two areas which witnessed riots on August 11. The sero survey was carried out by Bangalore Baptist Hospital, which has been providing primary healthcare in DJ Halli for a decade now.
“We took up the study in DJ Halli as it is one of the most tightly packed areas in the city. The surveyed area is a typical slum, where the likelihood of rapid spread of disease is high. According to the government’s Covid-19 data, the slum had reported only 295 positive cases and 17 deaths till early September. The official data sounded unrealistic,” said Dr Carolin Elizabeth George, the head of community health and research division at Bangalore Baptist Hospital. She led the study.
Though a challenging task, investigating the seroprevalence of Covid-19 in DJ Halli was critical for the researchers as they planned health and social interventions. Infections were peaking in Bengaluru at the time.
The researchers designed a cross-sectional seroepidemiological survey based on the recommendations of the World Health Organization (WHO). The locality comes under two BBMP wards and they took this fact into account while selecting 499 respondents for the study.
Blood samples were collected at a kiosk set up in the area. About 5ml of blood was taken from each participant and the samples were sent for tests to the hospital’s lab within five hours.
Of the 499 participants, 289 (nearly 58 per cent) tested positive for IgG antibodies for Covid-19, which suggested past infection. The researchers said that the majority of the seropositive individuals
(95.2 per cent) didn’t report any Covid-19 symptoms at the time of the study or earlier.
The study found that the area’s case-to-undetected-infections ratio (CIR) was 1:195, meaning that there were 195 undetected infections for every diagnosed case.
The findings of high Covid-19 seroprevalence in DJ Halli are consistent with the results of surveys conducted in Mumbai slums, where prevalence of 57.9 per cent was noted three months past index case. “If we extrapolate our findings to the entire DJ Halli slum, 57,900 people would have contracted the infection as against 295 cases that had been officially reported,” said Dr George. “According to researchers, this is not surprising, given the hazardous physical environment, overcrowding, poor sanitation and the impracticability of social distancing, hand washing and face coverings in the area.”
The study has been sent to a peer-reviewed international journal for publication.
An estimated 1 lakh people live in the 1.5-sqkm locality, one of the two areas which witnessed riots on August 11. The sero survey was carried out by Bangalore Baptist Hospital, which has been providing primary healthcare in DJ Halli for a decade now.
“We took up the study in DJ Halli as it is one of the most tightly packed areas in the city. The surveyed area is a typical slum, where the likelihood of rapid spread of disease is high. According to the government’s Covid-19 data, the slum had reported only 295 positive cases and 17 deaths till early September. The official data sounded unrealistic,” said Dr Carolin Elizabeth George, the head of community health and research division at Bangalore Baptist Hospital. She led the study.
Though a challenging task, investigating the seroprevalence of Covid-19 in DJ Halli was critical for the researchers as they planned health and social interventions. Infections were peaking in Bengaluru at the time.
The researchers designed a cross-sectional seroepidemiological survey based on the recommendations of the World Health Organization (WHO). The locality comes under two BBMP wards and they took this fact into account while selecting 499 respondents for the study.
Blood samples were collected at a kiosk set up in the area. About 5ml of blood was taken from each participant and the samples were sent for tests to the hospital’s lab within five hours.
Of the 499 participants, 289 (nearly 58 per cent) tested positive for IgG antibodies for Covid-19, which suggested past infection. The researchers said that the majority of the seropositive individuals
(95.2 per cent) didn’t report any Covid-19 symptoms at the time of the study or earlier.
The study found that the area’s case-to-undetected-infections ratio (CIR) was 1:195, meaning that there were 195 undetected infections for every diagnosed case.
The findings of high Covid-19 seroprevalence in DJ Halli are consistent with the results of surveys conducted in Mumbai slums, where prevalence of 57.9 per cent was noted three months past index case. “If we extrapolate our findings to the entire DJ Halli slum, 57,900 people would have contracted the infection as against 295 cases that had been officially reported,” said Dr George. “According to researchers, this is not surprising, given the hazardous physical environment, overcrowding, poor sanitation and the impracticability of social distancing, hand washing and face coverings in the area.”
The study has been sent to a peer-reviewed international journal for publication.
