Cape Town - Following concern around the high levels of Sars-CoV-2 RNA in wastewater treatment plants in Cape Town and other parts of the Western Cape, prompting the issuance of a public alert, the South African Medical Research Council (SAMRC) has noted a significant decline since.
SAMRC conducts weekly wastewater testing of Sars-CoV-2 levels, with samples collected from more than 80 wastewater treatment plants across six provinces.
Covid-19 is caused by the virus Sars-CoV-2.
Increases were also found in De Doorns, Rawsonville and Worcester.
SAMRC Wastewater Surveillance team member Professor Angela Mathee said: “We’ve had several months of low levels of volatility, and then about two/ three weeks ago, we started seeing sharp increases at some sites, especially in Cape Town.
“In Cape Town, we saw the concentration of Sars-CoV-2 RNA increase in the majority of wastewater treatment plants, and they’ve increased to levels that we’ve last seen in waves four and five of the pandemic.”
However, last week, the sharp rise followed a very fast decline in Cape Town samples, Mathee said.
The National Institute for Communicable Diseases has also reported an increase in Covid-19 cases and test positivity rates.
“One thing is possible, is that we know that there are more cases around from the wastewater, there are more active cases of Covid-19, but they could have been asymptomatic or very mild cases, or cases mild enough for people to manage at home,” Mathee said.
Provincial Health and Wellness Department spokesperson Maret Lesch said that two weeks prior, Sars-CoV-2 levels in wastewater were above the threshold for concern at 22 out of 24 treatment plants in the Cape Town Metro, and all four treatment plants in Breede Valley.
The department saw an increase in diagnosed Covid-19 cases in mid-September, with daily cases increasing from about 20-25 cases in early September to 40-50 cases per day during the first week of October. .
“While this is a large relative increase in case numbers, the absolute number of cases remains at some of the lowest levels seen during the pandemic, although this is partly due to substantially reduced testing compared with earlier periods,” Lesch said.
On October 12, 2022, the department recorded 23 Covid-19 admissions to hospital, of which three were in ICU.