Universal Admission Screening for SARS-CoV-2 Infections among Hospitalized Patients, Switzerland, 2020

Abstract

Switzerland began a national lockdown on March 16, 2020, in response to the rapid spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We assessed the prevalence of SARS-CoV-2 infection among patients admitted to 4 hospitals in the canton of Zurich, Switzerland, in April 2020. These 4 acute care hospitals screened 2,807 patients, including 2,278 (81.2%) who did not have symptoms of coronavirus disease (COVID-19). Overall, 529 (18.8%) persons had > 1 symptom of COVID-19, of whom 60 (11.3%) tested positive for SARS-CoV-2. Eight asymptomatic persons (0.4%) also tested positive for SARS-CoV-2. Our findings indicate that screening on the basis of COVID-19 symptoms, regardless of clinical suspicion, can identify most SARS-CoV-2–positive persons in a low-prevalence setting.

Pitfall of Universal Pre-Admission Screening for SARS-CoV-2 in a Low Prevalence Country

“…Significant higher positive rates in symptom- or epidemiologic risk-based screening than in pre-admission testing for asymptomatic patients was shown in our study. Similar to our finding, a Swiss study [ 11 ] showed that 8 of 2278 (0.4%) asymptomatic patients had positive universal admission screening tests, while 11.3% (60/529) of symptomatic patients had a positive test. The absence of COVID-19 symptoms or signs yielded a negative predictive value of 99.6% in the median daily incidence of 40 cases (IQR 27-87 cases) corresponding to a rate of 2.7 cases/100,000 inhabitants.…”

Coronavirus disease 2019 (COVID-19) admission screening and assessment of infectiousness at an academic medical center in Iowa, 2020

“…Previous studies revealed that SARS-CoV-2 positivity on admission screening or pre-procedural screening was seen in 0.3-13% of asymptomatic patients 5,18,19 . In low COVID-19 prevalence areas, universal hospital admission testing does not yield a considerable number of asymptomatic COVID-19 cases as community incidence rates may correlate with the incidence of asymptomatic cases 25,26 . In our study, we found that positive SARS-CoV-2 RT-PCR in patients admitted for reasons unrelated to COVID-19 represented only 1.1% of hospital admissions .The wide range of positivity in different studies is likely due to different definitions of symptomatic vs. asymptomatic and community incidence.…”

“…Bullard et al documented that a combination of COVID-19 duration of symptoms and RT-PCR Ct values may determine COVID-19 infectivity 15 . However, previous studies evaluating the utility of admission screening did not use this strategy and could ot evaluate infectiousness in asymptomatic patients with positive RT-PCR 25,26 . In our study, we found that 58% of patients admitted for reasons unrelated to COVID-19 who tested positive were likely non-infectious.…”

Universal Polymerase Chain Reaction Screening for Severe Acute Respiratory Syndrome Coronavirus 2 in Asymptomatic Patients Before Hospital Admission in Tokyo, Japan

“…In this study, 0.07% of the asymptomatic patients and attendants tested positive for SARS-CoV-2 RNA by PCR before the scheduled admission. Regarding universal SARS-CoV-2 PCR screening before admission, Krüger et al [1] reported that 27 of 6,940 patients (0.4%) were positive at a tertiary care hospital in Germany, and Scheier et al [2] demonstrated similar results at four hospitals in Zurich (8 of 2,278 positive patients, 0.4%). These studies were conducted in areas where the COVID-19 prevalence was higher than in Tokyo.…”

“…Universal severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) polymerase chain reaction (PCR) screening before admission has been adopted in several hospitals to prevent nosocomial SARS-CoV-2 transmission from asymptomatic and pre-symptomatic patients. However, the usefulness of this type of screening remains unclear as it depends on the regional COVID-19 prevalence, and, to date, only a few large-scale studies have been conducted [1] , [2] , [3] . Here, we report the universal COVID-19 PCR screening results for over 12,000 asymptomatic patients and their attendants before admission to a hospital in Tokyo, Japan, to evaluate the universal screening benefits.…”