BMC to study city sewage water for Covid-19 variants

Mumbai: The Brihanmumbai Municipal Corporation (BMC) has decided to collect 1000 sewage water samples for RT-PCR testing to understand Covid-19 variants in the community. Experts said unlike other respiratory viruses, RNA [ribonucleic acid] of SARS-CoV-2 and other coronaviruses can be detected in human faeces.

Next week, the BMC is all set to test sewage samples from the city’s outfalls and conduct RT-PCR tests to study the presence of Covid variants. Samples that will test positive for Covid will undergo genome sequencing at the lab in Kasturba hospital. BMC officials said waste water surveillance will help them plan future policies and interventions.

“This is a new exercise that we plan to do to understand the variants of Covid-19 in the community. The sewage water samples testing positive in RT-PCR test will be sent for genome sequencing,” said Suresh Kakani, additional municipal commissioner, BMC.

He further explained, “We have the genome sequencing facility and so far, we have collected samples for genome sequencing from community, hospitals and people who have died of Covid-19. We now want to check the sewage water samples that will help us plan future policies and interventions.”

Since August 2021, BMC has carried out a total 10 surveys for genome sequencing to understand the pattern of Covid-19 spread in the community. In the latest survey, which was announced early this month, 237 samples that BMC’s health department had collected from patients belonging to different age groups and gender, were positive for the Omicron variant or its other subtypes.

Earlier, the Indian Institute of Technology Gandhinagar (IIT-Gn) had joined a global consortium of 51 premier universities and research institutes to undertake surveillance of sewage water to help determine and quantify excretion of the Sars-Cov-2 virus, which caused Covid-19. Recent studies have reported that in 27% to 89% of patients, the infection is accompanied by persistent shedding of virus RNA in stool.

Dr Rajesh Karyakarte, the state coordinator for genome sequencing and head of Microbiology department at BJ Government Medical College and Sassoon Hospital- Pune said with the third wave waning off, it is the right time to do sewage water sampling to understand presence of Covid-19 variants in the community. “Countries abroad are undertaking genome sequencing of sewage water samples that test positive for Covid-19. While it takes three to 14 days for an individual to exhibit symptoms of Covid-19, the presence can be seen in the wastewater early. It helps in rapid identification of variants in the community. In India, with the third wave declining, it is now time to be vigilant for new possible variants,” he said.

Global Covid deaths probably three times higher

More than 18 million people - three times higher than official records suggest - have probably died because of Covid, say researchers.

Their report comes two years to the day from when the World Health Organization first declared the pandemic.

The Covid-19 excess mortality team at the US's Washington University studied 191 countries and territories for what they call the true global death figure.

Some deaths were from the virus, while others were linked to the infection.

This is because catching Covid might worsen other pre-existing medical conditions, such as heart or lung disease, for example.

The measure used is called excess deaths - how many more people have been dying than would be expected compared to recent years, before the pandemic hit.

To calculate this, the researchers gathered data through searches of various government websites, the World Mortality Database, the Human Mortality Database, and the European Statistical Office.

Rates of excess deaths are estimated to have varied dramatically by country and region, but the overall global rate calculated in the study is 120 deaths per 100,000 people.

That would mean about 18.2 million deaths have happened because of Covid in the two years between the start of 2020 and the end of 2021 - three times as many as the official 5.9 million that have actually been recorded.

Excess death estimates were calculated for the full study period only, and not by week or month, because of lags and inconsistencies in reporting of Covid death data that could drastically alter the estimates, the investigators stress.

According to the research, which is published in The Lancet, the highest rates were in lower income countries in Latin America, Europe and sub-Saharan Africa. But deaths were also fairly high in some high-income countries, such as Italy and parts of the US.

The five countries with the highest estimated excess death rates were:

Bolivia

Bulgaria

Eswatini

North Macedonia

Lesotho

The five with the lowest were:

Iceland

Australia

Singapore

New Zealand

Taiwan

For the UK, the estimated total number of Covid-related deaths in 2020 and 2021 was similar to official records at about 173,000, with an excess mortality rate of 130 people per 100,000.

Lead author Dr Haidong Wang, from the Institute for Health Metrics and Evaluation, said: "Understanding the true death toll from the pandemic is vital for effective public health decision-making.

"Studies from several countries, including Sweden and the Netherlands, suggest Covid was the direct cause of most excess deaths, but we currently don't have enough evidence for most locations.

"Further research will help to reveal how many deaths were caused directly by Covid, and how many occurred as an indirect result of the pandemic."

The researchers predict that excess mortality linked to the pandemic will decline, thanks to vaccines and new treatments.

But they warn that the pandemic is not yet over. And new, dangerous variants of the virus could emerge.