Epidemiological and clinical characteristics of SARS-CoV-2 infections at a testing site in Berlin, Germany, March and April 2020-a cross-sectional study

Abstract

Objective: In Berlin, the first public severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing site started 1 day after the first case in the city occurred. We describe epidemiological and clinical characteristics and aim at identifying risk factors for SARS-CoV-2 detection during the first 6 weeks of operation.

Methods: Testing followed national recommendations, but was also based on the physician's discretion. We related patient characteristics to SARS-CoV-2 test positivity for exploratory analyses using a cross-sectional, observational study design.

Results: Between 3 March and 13 April 2020, 5179 individuals attended the site (median age 34 years; interquartile range 26-47 years). The median time since disease onset was 4 days (interquartile range 2-7 days). Among 4333 persons tested, 333 (7.7%) were positive. Test positivity increased up to 10.3% (96/929) during the first 3 weeks and then declined, paralleling Germany's lock-down and the course of the epidemic in Berlin. Strict adherence to testing guidelines resulted in 10.4% (262/2530) test positivity, compared with 3.9% (71/1803) among individuals tested for other indications. A nightclub was a transmission hotspot; 27.7% (26/94) of one night's visitors were found positive. Smell and/or taste dysfunction indicated coronavirus disease 2019 (COVID-19) with 85.6% specificity (95% CI 82.1%-88.1%). Four per cent (14/333) of those infected were asymptomatic. Risk factors for detection of SARS-CoV-2 infection were recent contact with a positive case (second week after contact, OR 3.42; 95% CI 2.48-4.71), travel to regions of high pandemic activity (e.g. Austria, OR 4.16; 95% CI 2.48-6.99), recent onset of symptoms (second week, OR 3.61; 95% CI 1.87-6.98) and an impaired sense of smell/taste (4.08; 95% CI 2.36-7.03).

Conclusions: In this young population, early-onset presentation of COVID-19 resembled flu-like symptoms, except for smell and/or taste dysfunction. Risk factors for SARS-CoV-2 detection were return from regions with high incidence and contact with confirmed SARS-CoV-2 cases, particularly when tests were administered within the first 2 weeks after contact and/or onset of symptoms.

Keywords: Asymptomatic; Coronavirus; Coronavirus disease 2019; Olfaction disorders; Screening; Severe acute respiratory syndrome coronavirus 2.

Fig. 1

Patient attendance and SARS-CoV-2 positivity. (a) Number of consultations, tests and positive cases by calendar week (which are shifted by 1 day and start on Tuesday). (b) Number of patients tested and tested positive if decision on testing strictly followed RKI recommendations. (c) Number of tested patients missed by RKI recommendations.

Fig. 2

Symptoms of patients tested positive and negative for SARS-CoV-2; crude, unadjusted odds ratios. Asterisk represents findings for a subset of n = 850 patients.