Hyderabad had 2.6 lakh active Covid-19 cases as of August first week, CCMB-IICT study reveals

Hyderabad alone had about 2.6 lakh active Covid-19 cases as of 6 August, a study by two premier central research institutions has revealed.

The figure is in stark contrast with the 21,417 cases shown as active in the whole of Telangana on the said date in the Covid-19 bulletin issued by the Chandrasekhar Rao government.

The collaborative study of the Centre for Cellular and Molecular Biology and the Indian Institute of Chemical Technology also estimated the overall number of potentially infected people in Hyderabad to be about 6.6 lakh, i.e., around 6.6 percent of the city’s population.

CCMB-IICT researchers have arrived at the numbers by analyzing the sewage samples collected from various locations in Hyderabad.

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Since an infected person sheds viral material in faecal samples for up to ~35 days, these studies provide an overall estimate of the situation in a window of one month, the CSIR-IICT researchers assert pointing at the similar active case numbers even now.

Individuals infected by SARS-CoV-2 shed virus not only through nasal and oral routes but also through their faeces. However, the SARS-CoV-2 in sewage samples is non-infectious, making it suitable for epidemiological studies.

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About 40 percent of the 1800 million litres water consumed daily in Hyderabad is processed at different sewage treatment plants. Sewage samples from major STPs were processed for detecting the presence of SARS-CoV-2 viral RNA.

The study covering about 80 percent of the STPs in Hyderabad showed that there are over two lakh people who were shedding viral materials as of August first week.

“Since only 40 percent of Hyderabad sewage reaches STPs, this data was used to extrapolate the overall number of potentially infected people which turned out to be approximately 6.6 lakhs, i.e., around 6.6 percent of the city’s population. This includes symptomatic, asymptomatic, and also recently recovered individuals in a time window of about 35 days. A conservative estimate of the number of active cases who are shedding the virus maybe around 2.6 lakhs,” the researchers stated.

“As the last faecal sample was collected on 6 August, the 2.6 lakh active case estimate can be said to be of that date,” Dr Rakesh Mishra, director, CCMB told DH.

While viral RNA was detectable in the inlet samples, the outlet (after treatment) samples were largely clean (free from viral RNA), indicating efficient treatment practices at STPs.

The experiments were conducted at the CSIR-CCMB Covid-19 testing facility and the findings posted on preprint server MedRxiv are yet to be peer-reviewed.

“Our findings clearly indicate that a large proportion of the affected individuals are asymptomatic needing no hospitalization. This is also in agreement with observations that hospitalization rush or mortality is way lower than otherwise expected with such a large infection rate at a given time. It also explains why our healthcare system was able to handle the situation reasonably well during this pandemic,” Dr Mishra said.

Estimating the virus spread is crucial in identifying the affected areas and controlling the pandemic.

“Such studies carried out in coordination with the civic bodies identifying the hotspots and monitoring the dynamics of the infection rate can assist the system in taking appropriate measures,” Dr Mishra says.

As of Tuesday 18 August, Telangana has a total 95,700 cases and active cases are 20,990, as shown in the Covid-19 bulletin.

The Rao government is accused of not conducting enough tests, which the opposition parties say is not revealing the true extent of the virus prevalence in the state. Telangana has till now conducted about eight lakh tests, with only 21,480 samples tested per a million population.