Lack of symptoms, late detection led to widespread Covid infection in Chandigarh’s Bapu Dham Colony, says study

A research study on the widespread outbreak of Covid-19 in Bapu Dham Colony, Sector 26, has shown that dense population coupled with a huge number of asymptomatic infections, which also led to late detection and delay in isolation of patients, resulted in the high number of virus cases in the locality.

The colony had emerged as one of the biggest virus hotspots in the neighbouring states of Punjab, Haryana, and Himachal Pradesh with Chandigarh ranking fourth in the number of cases per million in the last week of May 2020.

The research study was conducted by Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, and also appeared in the journal of primary care and community health states.

As per the findings, the index case (patient zero) was living in a densely populated and low-income settlement where physical distancing between the individuals is not possible and had high number of community contacts. This, along with asymptomatic infections, was responsible for the late detection and delayed isolation of cases leading to the widespread outbreak, the study states.

Major hotspot

The index case was a 33-year-old who worked as an operation theatre attendant at Government Medical College and Hospital (GMCH), Sector 32, and was diagnosed for Covid-19 on April 24. Till June 1, 222 out of 293 (76%) of the city’s Covid cases had surfaced from Bapu Dham alone. The number of cases in the area touched almost 300-mark even when the strict lockdown was in force.

While the authorities scrambled to control the spread, a team of experts from PGIMER was formed to visit the area and suggest steps to contain the virus. The team at the time had suggested the identification of superspreaders and active surveillance for the detection of cases in the area.

‘The superspreader’

The index case had a total of 11 family contacts, of which 8 were household contacts and the other three were his relatives who were staying in a different house, but had visited him.

In all, he had 125 contacts, of which 65 were community contacts and 60 were from the workplace. A total of 34 community contacts and six workplace contacts were positive for Covid-19. Therefore, in total, 49 Covid infections had direct or indirect contact with the index case, qualifying him as a “superspreader”.

Researchers have claimed that this case remains the first reported case of documented Covid-19 superspreader with an unusually high number of secondary infections.

Another limitation was that 10 community members belonging to three families, who were contacts of index case, were only screened and not tested by RT-PCR. Moreover, in the case of asymptomatic contacts who had tested negative at first, repeat testing was not done between Day 5 and 14. Repeat testing in such cases is recommended, as it is difficult to assess the last date of exposure in and the limited sensitivity of the RT-PCR test.

The researchers have suggested preventing such super-spreading events in the community, besides highlighting the need for behaviour change communication emphasising early reporting to a health facility if a person develops influenza-like-illness symptoms.