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Mass Screening for SARS-CoV-2 Uncovers Significant Transmission Risk from Asymptomatic Carriers

45 Pages Posted: 4 Dec 2020

See all articles by Paul Wilmes

Paul Wilmes

Universite du Luxembourg - Luxembourg Centre for Systems Biomedicine

Jacques Zimmer

Luxembourg Institute of Health

Jasmin Schulz

Department of Infection and Immunity, Luxembourg Institute of Health (LIH)

Frank Glod

Luxembourg Institute of Health (LIH)

Lisa Veiber

University of Luxembourg - Interdisciplinary Centre for Security, Reliability and Trust

Laurent Mombaerts

University of Luxembourg - Luxembourg Centre for Systems Biomedicine

Bruno Rodrigues

Ministry of Higher Education and Research

Atte Aalto

Universite du Luxembourg

Jessica Pastore

Luxembourg Institute of Health (LIH)

Chantal J. Snoeck

Department of Infection and Immunity, Luxembourg Institute of Health (LIH)

Markus Ollert

Luxembourg Institute of Health - Department of Infection and Immunity

Guy Fagherazzi

Luxembourg Institute of Health (LIH)

Joël Mossong

Health Directorate

Jorge Goncalves

University of Luxembourg

Alexander Skupin

Universite du Luxembourg - Center for Systems Biomedicine

Ulf Nehrbass

Luxembourg Institute of Health (LIH)

More...

Abstract

Background: To accompany the lifting of COVID-19 lockdown measures, Luxembourg implemented a mass testing programme. The first phase coincided with an early summer epidemic wave.

Methods:  High-throughput rRT-PCR was performed using a validated pooling strategy. The sampling infrastructure allowed the testing of the resident and cross-border worker populations. Test strategy was based on social connectivity within different activity sectors. Invitation frequencies were tactically increased in sectors and regions with higher prevalence. The results were analysed alongside contact tracing data.

Findings: Sensitivity and specificity of the test protocol were 100%. The tests covered 49% of the resident and 22% of the cross-border worker populations. The programme identified 850 index cases with an additional 249 cases resulting from contact tracing, corresponding to 26% of positive cases of the epidemic wave. Enrichment in positive cases was observed in the services (11·4% increase over the mean prevalence), hospitality (8·6%) and construction (6·6%) sectors alongside regional differences. Strikingly, cases that were asymptomatic on the day of the positive result had a similar secondary attack rate in the household compared to those who were symptomatic. Based on simulations using a tailored agent-based SEIR model, the total number of expected cases would have been 39·1% higher without the mass screening programme. Mandatory participation would have resulted in a further difference of 41·4%.

Interpretation: The implementation of strategic and tactical mass testing for SARS-CoV-2 allows the breaking of nascent infection chains and the suppression of epidemic dynamics. Asymptomatic carriers are at least as infectious as symptomatic patients. Containment of future outbreaks will critically depend on early testing in sectors and geographical regions. Higher participation rates must be assured through targeted incentivisation and recurrent invitation.

Funding:  This project was funded by the Luxembourg Ministries of Higher Education and Research, and Health.

Declaration of Interests: All authors report grants from Luxembourg Ministry of Higher Education and Research, and Ministry of Health during the conduct of the study. Dr. Rodrigues reports working for the Ministry of Higher Education and Research as a public servant, during the conduct of the study. Dr. Snoeck reports that Fast Track Diagnostics provided a few SARS-CoV-2 rRT-PCR kits (RUO) free of charge at the time of evaluation of different commercial assays to be procured by the Luxembourg Government in order to do the mass screening intervention in the country.

Ethics Approval Statement: The study was presented to the National Research Ethics Committee of Luxembourg (Comité National d’Ethique de Recherche, CNER) that approved its submission in its current form (ref. 1120-218).

Keywords: Asymptomatic; contact tracing; COVID-19; mass screening; rRT-PCR; SARS-CoV-2

Suggested Citation

Wilmes, Paul and Zimmer, Jacques and Schulz, Jasmin and Glod, Frank and Veiber, Lisa and Mombaerts, Laurent and Rodrigues, Bruno and Aalto, Atte and Pastore, Jessica and Snoeck, Chantal J. and Ollert, Markus and Fagherazzi, Guy and Mossong, Joël and Goncalves, Jorge and Skupin, Alexander and Nehrbass, Ulf, Mass Screening for SARS-CoV-2 Uncovers Significant Transmission Risk from Asymptomatic Carriers. Available at SSRN: https://ssrn.com/abstract=3738086 or http://dx.doi.org/10.2139/ssrn.3738086

Paul Wilmes (Contact Author)

Universite du Luxembourg - Luxembourg Centre for Systems Biomedicine ( email )

2 Avenue de l'Université
Esch-sur-Alzette
Luxembourg

Jacques Zimmer

Luxembourg Institute of Health ( email )

Luxembourg
352 26 97 02 60 (Phone)

Jasmin Schulz

Department of Infection and Immunity, Luxembourg Institute of Health (LIH) ( email )

Frank Glod

Luxembourg Institute of Health (LIH) ( email )

Lisa Veiber

University of Luxembourg - Interdisciplinary Centre for Security, Reliability and Trust ( email )

Kirchberg, 6, rue Richard Coudenhove-Kalergi
Luxembourg
Luxembourg

Laurent Mombaerts

University of Luxembourg - Luxembourg Centre for Systems Biomedicine ( email )

L-1511 Luxembourg
Luxembourg

Bruno Rodrigues

Ministry of Higher Education and Research

Atte Aalto

Universite du Luxembourg ( email )

L-1511 Luxembourg
Luxembourg

Jessica Pastore

Luxembourg Institute of Health (LIH)

Chantal J. Snoeck

Department of Infection and Immunity, Luxembourg Institute of Health (LIH) ( email )

Markus Ollert

Luxembourg Institute of Health - Department of Infection and Immunity ( email )

Luxembourg

Guy Fagherazzi

Luxembourg Institute of Health (LIH)

Joël Mossong

Health Directorate ( email )

Luxembourg

Jorge Goncalves

University of Luxembourg ( email )

6, avenue du Swing
Belvaux, 4367
Luxembourg

Alexander Skupin

Universite du Luxembourg - Center for Systems Biomedicine ( email )

7, avenue des Hauts-Fourneaux
Esch-sur-Alzette, L-4362
Luxembourg

Ulf Nehrbass

Luxembourg Institute of Health (LIH) ( email )

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