COVID-19 —Analysis of Incident Cases Reported Within the German Healthcare System

Outbreaks of COVID-19 in healthcare institutions present a significant challenge. These outbreaks mostly affect elderly people and those with underlying illnesses, therefore, the disease often takes a severe course. Resultant staff absences and quarantine measures can additionally hamper healthcare delivery.In order to deduce preventive measures, we describe COVID-19 infection trends in the healthcare system on the basis of an analysis of reported incident cases.

Method

The evaluation is based on incident cases reported to health offices in accordance with the SARS-CoV-2 reference definition (1) and Germany’s Infection Protection Act (IfSG) which are notified to the Robert Koch Institute (RKI) by the state authorities. Demographic information, hospital admissions, and death among the COVID-19 cases notified up to 30 September 2020 including the 38th calendar week were stratified by nosocomial outbreaks and by known employement in a healthcare institution (health facility staff).

We considered nosocomial outbreaks according to § 6 section 3 IfSG as well as outbreaks for which a healthcare institution (hospital, rehabilitation center, medical treatment center, outpatient treatment center) was documented under the tab “Settings”. We dated each outbreak according to the reported date of its first known case. The case-fatality rate corresponds to the proportion of deaths among the notified outbreak cases per in one calendar week.

Staff of healthcare facilities includes persons who work in an institution according to § 23 IfSG (for example, hospitals, doctors’ practices, dialysis centers, outpatient care services). No distinction is possible between staff in active medical occupations and those in non-medical occupations.

Results

Up to calendar week (CW) 38 (30 September 2020), 273 720 laboratory confirmed COVID-19 cases were notified. Up to CW14, the number of COVID-19 cases per calendar week rose to 36 070, then fell to 2352 cases in CW23, before climbing again to 12 210 in CW38 (figure 1). The median age was 43 years (interquartile range 27–58 years). 9467 deaths were notified (case-fatality rate 3.5%).

Figure 1.

Reported incident cases of COVID-19

The figure shows total numbers of reported cases in the population, the number of outbreaks in healthcare institutions, reported cases in the context of outbreaks, the staff infected thereby, and the total number of all healthcare staff reported as infected, respectively.

To the end of September 2020, 994 nosocomial outbreaks of COVID-19 were notified, with a total of 9856 cases (of which 69.7% in patients and 30.3% in staff), 1087 deaths (four of which in staff), and a median case number of five cases per outbreak (range 2–198). All federal states (Länder) were affected. The overall median age was 56 years (IQR 39–80 years) and when only patients were considered, 68 years (IQR 45083 years). The proportion of patients older than 60 was almost 70% in CW18, fell to 20% over the summer, and in CW38 rose to above 30%. Of the 6874 patients affected by the nosocomial outbreaks, 4125 (60%) were female, 2732 (39.7%) male, and 17 diverse or not documented. The case fatality rate was 11.0%. The median age of the deceased was 83 years; 45.9% (n=499) of the deceased were women.

Altogether 15 946 COVID-19 cases (72.8% women/27.1% men) with an occupation in a healthcare setting were notified. The dynamics were similar to that of all reported cases, with a time-delayed upsurge at CW29 (figure 1). The proportion of staff among all notified cases for which data on their actual occupation were available (n=205 056) was 6.3% in CW11, rose to a maximum of 12.0% in CW16, continually fell up to CW25, to 1.8%, and subsequently remained at a low level (2.3–4.4%). The median age of the staff was 40 years. 4.7% of infected healthcare staff were admitted to hospital and 23 (0.1%) died in association with COVID-19.

For healthcare staff who within the 14 days before illness onset had been in contact with a COVID-19 case (6 365 of 10 077 for which relevant data were available), the reported contact location was their workplace in 75% and for 15.6% their private household (9.3% other/elsewhere). In CW17, the ratio of cases with contact to a known case at the workplace rose up to 10.6 compared to those with contacts in private settings, and subsequently showed a downward trend (figure 2).

Figure 2.

Exposure to a COVID-19 case

Percentage of notified cases among staff in medical institutions with exposure to a COVID-19 case at home, in the workplace, or elsewhere of all notified cases with case contact among staff in medical institutions (n = 6 365).

Ratio of cases with contact to a COVID-19 case in the workplace and cases with contact to a COVID-19 case at home.

Discussion

Dynamics of case numbers of infected staff was similar to the dynamics in the general population; however, the recurrent upsurge in case numbers occured with a time lag. Underreporting of cases in medical institutions seems possible because relevant data were often lacking. The fact that staff was affected particularly strongly is also reflected in the high rate (30%) of staff among outbreak cases. Owing to undetected cases and infected staff, nosocomial outbreaks can also contribute to the further spread of SARS-CoV-2 into the general population (2). The proportion of cases in staff among all reported cases fell over time. One reason may be improvement of prevention measures in healthcare facilities over time.

While may COVID-19 cases occurred, healthcare staff were mostly infected in their workplaces. During the further course, the proportion of infected patients with household contact increased.

The higher rates of deceased patients in nosocomial outbreaks compared to the general population underlines the risk for a severe course of disease among hospitalized individuals.

Healthcare institutions are particularly affected by the COVID-19 pandemic. The RKI published recommendations for preventive measures (3– 5). Further improvement of infection control measures can help to prevent healthcare facilities to become again locations with a higher infection risk. Therefore, fixed structures should be established, to ensure their preparedness for future epidemics.