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Volume 27, Number 4—April 2021

Analysis of Asymptomatic and Presymptomatic Transmission in SARS-CoV-2 Outbreak, Germany, 2020

Jennifer K. Bender1Comments to Author , Michael Brandl1, Michael Höhle, Udo Buchholz, and Nadine Zeitlmann
Author affiliations: Robert Koch Institute, Wernigerode, Germany (J.K. Bender); European Centre for Disease Prevention and Control, Stockholm, Sweden (J.K. Bender, M. Brandl); Robert Koch Institute, Berlin, Germany (M. Brandl, M. Höhle, U. Buchholz, N. Zeitlmann); Stockholm University, Stockholm (M. Höhle); Federal Institute for Quality Assurance and Transparency in Healthcare, Berlin (M. Höhle)

Main Article

Table 2

Secondary attack rates among contacts of coronavirus disease case-patients in a district in southern Germany*

Clinical symptoms of source case No. contacts tested positive or experienced respiratory symptoms Total no. contacts SAR, % RR (95% CI)
Household contacts SARlab
Asymptomatic 0 4 0 Reference
Symptomatic, phase not specified or both† 4 28 14.3 0.8 (0.09–∞)

Household contacts SARres
Asymptomatic 0 7 0 Reference
Symptomatic, phase not specified or both 12 35 34.3 3.4 (0.56–∞)

Other contacts SARlab
Asymptomatic cases 0 22 0 Reference
Symptomatic, phase not specified or both 3 25 12.0 3.4 (0.36–∞)
Symptomatic, presymptomatic phase only 15 72 20.8 6.5 (1.1–∞)
Symptomatic, symptomatic phase only 2 29 6.9 1.8 (0.14–∞)

Other contacts SARres
Asymptomatic cases 2 52 3.8 Reference
Symptomatic, phase not specified or both 4 22 18.2 4.7 (0.68–52)
Symptomatic, presymptomatic phase only 22 67 32.8 8.5 (2.1–75)
Symptomatic, symptomatic phase only 1 29 3.5 0.90 (0.02–17)
Total 29 170 17.1

*RR relative risk; SAR, secondary attack rate; SARlab secondary attack rate for laboratory-confirmed SARS-CoV-2–positive contact persons; SARres, secondary attack rate for contact persons who experienced respiratory symptoms after contact. 
†The phase in which the contact occurred was not specified, or contact occurred in both phases.

Main Article

1These first authors contributed equally to this article.

Page created: February 18, 2021
Page updated: March 18, 2021
Page reviewed: March 18, 2021
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