Covid cases: Wastewater surveillance in Bengaluru shows slowing down of infection

“It appears that over the past two weeks, there hasn’t been the same rapid increase in cases as before, although there hasn’t been a reduction either. The rate of increase seems to be slowing down, but it’s not yet clear whether this trend will continue or if it’s just a temporary fluctuation,” TIGS Director Dr Rakesh Mishra told South First.

“Typically, these peaks tend to come and go within 6 to 8 weeks. We may be approaching that point soon. Other areas like Pune or Hyderabad are displaying similar trends — sometimes high, sometimes a bit lower,” he added.

What does the surveillance say?

The surveillance shows the viral load of SARS-CoV-2 — Covid 19 — in the wastewater that comes from the households of the community. For more information about how it works, read here.

Between 10 December and 15 December, the SARS-CoV-2 copies per ml were 2,000, however, in the last week of December, it increased to more than 3,000 copies per ml. This has stayed at the same level in the current update.

In some areas near Yele Mallapa Chetti Kare, Raja Canal, and Horamavu Agara STPs in East Bengaluru, the SARS-CoV-2 viral load is more than 30,000 copies per ml, TIGS reported.

#Realtime #SARSCoV2 viral load in sewershed sites #wastewaters and reported #COVID-19 cases – the viral load shows an increase and mainly driven by #JN.1 variant and its sublineages.

There is no clinical testing data available since 8th Nov. pic.twitter.com/bhUDYaCMyr

— Tata Institute for Genetics and Society, India (@TIGS_India) January 8, 2024

“It seems unlikely that we’re heading toward an uncontrollable peak, but it’s too early to confirm a downward trend. We have to wait and see because things can change unexpectedly. The rise in cases is still apparent, but the pace at which the cases are increasing has slowed down over the past couple of weeks. This might indicate the beginning of a decline or it could be due to various factors like sampling or chance events, which might change the scenario later,” said Dr Mishra.

Dr Mishra added that they would need at least two more weeks to determine if we have reached the other side of this invisible peak or if there’s still a longer wait ahead.

Wastewater surveillance also provides insights into the positivity rate. The load of the virus in the wastewater hasn’t risen as steeply as it did from the middle of November to early December.

“It seems to be slowing down now, suggesting that we might be approaching the other side of the peak,” Dr Mishra said.

At present, it doesn’t seem like the peak is just beginning, but definitive conclusions will require more time and data analysis.

Also Read: What is wastewater surveillance? Will it help check disease outbreaks?

JN.1 cases in India

Kerala has reported the highest number of JN.1 cases in India at 154 as of Monday, 8 January, followed by Maharashtra (111), Gujarat (76), Goa (51), Telangana and Rajasthan (32), Andhra Pradesh (29), Tamil Nadu (22), Delhi (16), Karnataka (8), Odisha (3), and West Bengal (2).

India, overall, reported 536 cases of the variant since November 2023, according to the Indian SARS-CoV-2 Genomics Consortium (INSACOG).

The World Health Organization (WHO) designated the SARS-CoV-2 subvariant JN.1 as a distinct “variant of interest” (VOI) from its original lineage BA.2.86 due to its rapid proliferation.

The earliest known case of the JN.1 variant emerged in Kerala on 10 November, when a male patient tested positive for Covid, prompting his samples to undergo genomic sequencing.

Also read: Study reveals 12 key symptoms commonly associated with long-Covid

Covid cases in India

India has recorded 605 new cases of Covid, while the number of active cases of the infection stood at 4,049, the Union Health Ministry said its website on Monday.

Four deaths — two each from Kerala and one each from Karnataka and Tripura — have been reported in a span of 24 hours, according to the ministry’s data updated at 8 am.

Karnataka reported 329 fresh Covid cases, while Kerala reported 69 cases, Tamil Nadu 20 cases, Andhra Pradesh and Telangana 5 cases each, respectively.

The number of daily cases was in the double digits till 5 December, 2023, but cases began to again increase after the emergence of a new variant and cold weather conditions.

After 5 December, a maximum increase in single-day cases was reported on 31 December, when 841 cases were reported across India.

Of the total active cases, a large majority of these (around 92 percent) are recovering under home isolation.

The currently available data suggests that the JN.1 variant is neither leading to an exponential rise in the new cases nor a surge in hospitalisation and mortality.

“The number of cases depends on the extent of testing. More testing tends to uncover more cases, while less testing reveals fewer cases. Thus, the current testing levels may not accurately reflect the positivity rate in the population,” said Dr Mishra.

Also Read: Survey finds majority in Telangana, Karnataka skipped Covid-19 tests

Covid through the years

India has witnessed three waves of Covid in the past with the peak incidence of daily new cases and deaths being reported during the Delta wave in April-June 2021. At its peak, 4,14,188 new cases and 3,915 deaths were reported on 7 May 2021.

Since the pandemic began in early 2020, more than 4.5 crore people have been infected and over 5.3 lakh died.

The number of people who have recuperated from the disease stands at over 4.4 crore with a national recovery rate of 98.81 percent, according to the ministry’s website.

According to the Health Ministry, 220.67 crore doses of Covid vaccines have so far been administered in the country.