COVID-⁠19 Switzerland

Information on the current situation, as of 28 November 2023

The key figures will be published each Tuesday at 15:30.

The Dashboard Covid-⁠19 will no longer be updated after 28.11.2023. From now on you will find the data publication and visualizations on Covid-⁠19, influenza and other respiratory pathogens on the Infectious Diseases Dashboard (IDD).

Epidemiological course,Grisons

Viral load in wastewater

The data published here are based on information obtained from the federal government's national wastewater monitoring system. Since January 2022, the national wastewater monitoring system of Switzerland and the Principality of Liechtenstein has determined the SARS-⁠CoV-⁠2 viral load in the wastewater of participating wastewater treatment plants (WWTP) at regular intervals.

Until June 2023 wastewater samples were collected three to six times per week, depending on the WWTP. Since then, samples are collected five times per week in all WWTPs. The absolute viral load (gene copies/day) is specified per 100,000 inhabitants. A dilution factor based on the wastewater treatment plant's flow volume is taken into account, for instance during dry periods. The relative viral load is the measured viral load (gene copies/day) as a proportion of the historically measured maximum value. The proportion of relative viral load is calculated by dividing the proportion of the absolute viral load by the proportion of the historic maximum viral load value. The residential population comprises the catchment area of each wastewater treatment plant. Seasonal fluctuations in the non-⁠permanent population, which influence the viral load particularly in busy tourist areas, are not included. Wastewater treatment plants no longer participating in the monitoring will not be included when calculating the WWTP’s proportion per viral load category. However, historical measurements will still be available when viewing the development over time.

Detailed information on the measuring methods and terminology can be found on the Eawag website. New findings may prompt adjustments to data calculations. From July 2023 onwards, 14 WWTPs participate in the monitoring and all analyses are carried out centrally in one laboratory by Eawag. This has led to a change in the analytical laboratory for the WWTPs in Basel, Region Bern, Neuchâtel, Zuchwil (Solothurn-⁠Emme), Lausanne (Vidy), Schwyz, Porrentruy (SEPE) and Luzern (Buholz), which makes the data less comparable with previous data. During the transition phase, the analyses were briefly interrupted. In certain cases, modifications to the sampling process and/or lab methodologies reduce comparability with older data. This concerns the wastewater treatment plants in Burgdorf (whose sampling scheme was modified with effect from 23 August 2022) as well as Aarau, Aarburg, Appenzell (Boedeli), Baden, Bremgarten, Brugg, Hallau (Klettau), Kaisten, Lenzburg, Neuhausen am Rheinfall (Roeti), Ramsen (Bibertal-⁠Hegau), Wohlen and Zofingen (whose lab methodologies were modified with effect from 30 October 2022).
The timeframe desired can be selected using the slider below the chart.

Geographical distribution

Viral load in wastewater, Grisons, 07.02.2022 to 27.11.2023

The graph shows the relative viral load in per cent as a 7-⁠day average in the wastewater treatment plants (WWTPs) and the difference in viral load compared with the previous week in percentage points (pp) in Switzerland and Liechtenstein. The percentage point figure is used to compare percentages. The 7-⁠day relative share refers to the historical maximum values for each wastewater treatment plant.
Cant. Name Population coverage Relative viral load Difference to previous week
BE Laupen BE Laupen 62 000 83,3% 12,2
BE Region Bern BE Region Bern 224 557 97,0% 13,5
BS Basel BS Basel 273 075 34,7% −6,3
GE Aire GE Aire 451 771 71,6% −14,7
GR Chur GR Chur 55 000 21,9% −3,7
JU Porrentruy (Sepe) JU Porrentruy (Sepe) 16 500 98,1% 52,3
LU Buholz (Real) LU Buholz (Real) 183 511 97,9% 34,6
NE Neuchatel NE Neuchatel 40 697 100,0% 18,7
SG Altenrhein SG Altenrhein 64 000 51,1% −23,1
SO Zuchwil (Soloth.-Emme) SO Zuchwil (Soloth.-Emme) 95 793 80,0% 6,4
SZ Schwyz SZ Schwyz 31 164 84,8% 3,5
TI Lugano TI Lugano 124 000 99,1% 20,5
VD Lausanne (Vidy) VD Lausanne (Vidy) 247 824 74,6% −2,2
ZH Werdhölzli ZH Werdhölzli 471 000 52,7% −34,8
Source: FOPH – Status: 28.11.2023, 08.00h
Geographic distribution over time

View the development of the virus load in wastewater at various WWTPs in Switzerland and Liechtenstein.


Development over time

The graph shows the absolute and the relative viral load in per cent as a 7-⁠⁠day average in the wastewater treatment plants (WWTPs) in Switzerland and Liechtenstein and the difference in viral load compared with the previous week’s 7-⁠day average in percentage points (pp). The 7-⁠⁠day relative share refers to the historical maximum values for each wastewater treatment plant. Vertical lines indicate changes in methodology (including a change in the analytical laboratory). Shaded areas indicate data points that are below the limit of quantification (LoQ).

Data only available for individual WWTP
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