Universal SARS-CoV-2 RT-qPCR admission screening over 21 months in a German tertiary care hospital: detection of asymptomatic infections

Numerous nosocomial infections were observed in hospitals and other healthcare facilities during the COVID-19 pandemic, largely attributed to asymptomatic or pre-symptomatic carriers. SARS-CoV-2 screening data at admission of all hospitalised patients and accompanying persons of a tertiary-care hospital in Germany was included from 1 April 2020 to 31 December 2021. The first oropharyngeal swab of each newly admitted individual was tested for SARS-CoV-2 RNA using reverse transcription polymerase chain reaction (RT-qPCR). The overall testing costs and the costs per positively tested individual were analysed. Out of 111,271 screened individuals, 705 (0.6%) tested positive for SARS-CoV-2 by RT-qPCR. Among these, 236 cases (0.2%) had not been previously diagnosed and were identified through RT-qPCR admission screening. Of the newly detected cases,110 (0.1%) were asymptomatic without any known positive contact history. The specificity of RT-qPCR in screening use was 99.997% (95% CI 99.992-99.999%). The mean testing costs of identifying one SARS-CoV-2-positive individual through admission screening was €8,082.87. Long-term universal RT-qPCR admission screening detected a substantial number of otherwise unidentified SARS-CoV-2-positive individuals, proving its value as a infection control tool with an excellent specificity in screening use during the COVID-19 pandemic. This strategy represents an important lesson learned from the pandemic and may serve as a valuable infection control tool for future pandemics or seasonal pathogen surges.