What's going around in Germany?

The total is estimated qualitatively from the ARE rate in the population and the RKI's consultation incidence. The overall picture is categorised in steps from “low” to “high”, based on the share of people with acute respiratory symptoms. Since not everyone who is ill sees a doctor, experts combine primary-care data with self-reports from GrippeWeb. For concrete numbers and personal risk assessment, the InfectRisk app provides deeper analysis.

The highest disease burden is consistently observed in winter. The peak usually falls between January and March, when flu, RSV, and COVID-19 often circulate simultaneously. Autumn also tends to show a clear uptick, as temperatures drop and the summer holidays end. Climate and increased time spent indoors favour the spread of respiratory pathogens.

Several factors contribute. Many viruses remain stable in the cold and survive longer in dry heated air. Airway mucous membranes are less perfused and drier in winter, weakening their barrier function. Close contact indoors eases transmission via droplets and aerosols. The net effect: the reproduction number of many respiratory pathogens naturally rises during winter.

“Immune debt” describes the phenomenon that, after periods of low pathogen circulation, for instance during strict public-health measures, population-level immunity against certain viruses drops. Subsequent infection waves can therefore hit harder, because the regular “training” of the immune system was missing. It does not describe a permanent defect, only a temporary catch-up effect.

Several data streams come together: the RKI uses reports on doctor visits for respiratory infections and virological lab results. Statutory health insurers add their view via sick-leave certificates for employees. These mosaic pieces together form a picture of current burden. On infectrisk.com we condense these streams into a single qualitative assessment.