According to the Robert Koch Institute (RKI), the corona numbers fell after Christmas and New Year. As the current weekly report shows, the number of infections and the incidence of hospitalization as well as the number of intensive care patients are decreasing.
But what does the wastewater look like? In fact, wastewater is an important indicator when analyzing the current infection dynamics. Corona infected people, who are sometimes unaware of their illness because of mild symptoms, excrete fragments of the Sars-CoV-2 virus when they go to the toilet. The viral load can therefore reflect the infection process somewhat more accurately than the incidence, which is less informative due to the greatly reduced test activity and the late reports still outstanding after the holidays.
Viral load in wastewater after Christmas and New Year
And the viral load in wastewater is currently decreasing. According to the Corona Pandemic Radar (as of January 10, 2024), 294,000 Covid-19 gene copies were discovered in one liter of wastewater between December 28, 2023 and January 3, 2024. That is 46 percent less than the previous week.
The data is based on wastewater samples from 89 sewage treatment plants from different cities in Germany. Your information speaks for 16.7 percent of the population. According to the current report from the wastewater monitoring for the epidemiological situation assessment (AMELAG), the viral load in the wastewater decreased in most of the 89 locations. According to AMELAG, a decline occurs when the viral load is more than 15 percent lower compared to the previous week.
The only seven cities in which more corona fragments were found in the wastewater than in the previous week are:
Braunschweig Glonn Hanover-Gümmerwald Schweinfurt Schwäbisch Hall Stadtbergen Straubing
According to AMELAG, the viral load was lowest in:
Aalen (6230) Göppingen (7500) Weil am Rhein (9340) Berg (9530) Saarlouis (9600)
The viral load was highest in:
Hetlingen (2,990,000) Braunschweig (3,300,000) Kiel (3,520,000) Ratzeburg (3,870,000) Grömitz (9,170,000)
The downward trend has already been apparent for several weeks. As the RKI reports, “after a steady increase since the end of June 2023, a decline in the Sars-CoV-2 load has been observed since mid-December 2023.” However, the information could vary – depending on how many of the 136 currently participating sewage treatment plants send their samples to the laboratory.
Consideration of different factors is necessary for evaluating corona infection events
The RKI also points out that the wastewater data “do not allow any conclusions to be drawn about the severity of the disease or the burden on the health system”. They could neither record the incidence nor the number of unreported cases.
In order to be able to comprehensively assess the corona infection process, other indicators, for example from syndromic surveillance, which provides information about the frequency and severity of the disease, would also have to be taken into account.