Open AccessRisk of Severe Acute Respiratory Syndrome Coronavirus 2 Acquisition Is Associated With Individual Exposure but Not Community-Level Transmission
Author(s) -
DeAnna Friedman-Klabanoff,
Meagan C. Fitzpatrick,
Meagan E. Deming,
Vaidehi Agrawal,
Sandra Sitar,
Torin T Schaafsma,
Elizabeth R. Brown,
Kathleen M. Neuzil,
Ruanne V. Barnabas,
Miriam K. Laufer,
AUTHOR_ID
Publication year - 2022
Publication title -
the journal of infectious diseases (online. university of chicago press)/the journal of infectious diseases
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.69
H-Index - 252
eISSN - 1537-6613
pISSN - 0022-1899
DOI - 10.1093/infdis/jiac029
Subject(s) - transmission (telecommunications) , betacoronavirus , covid-19 , medicine , coronavirus , respiratory system , severe acute respiratory syndrome coronavirus , virology , environmental health , immunology , disease , outbreak , computer science , telecommunications , infectious disease (medical specialty)
Background Transmission rates after exposure to a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)–positive individual within households and healthcare settings varies significantly between studies. Variability in the extent of exposure and community SARS-CoV-2 incidence may contribute to differences in observed rates. Methods We examined risk factors for SARS-CoV-2 infection in a randomized controlled trial of hydroxychloroquine as postexposure prophylaxis. Study procedures included standardized questionnaires at enrollment and daily self-collection of midturbinate swabs for SARS-CoV-2 polymerase chain reaction testing. County-level incidence was modeled using federally sourced data. Relative risks and 95% confidence intervals were calculated using modified Poisson regression. Results Eighty-six of 567 (15.2%) household/social contacts and 12 of 122 (9.8%) healthcare worker contacts acquired SARS-CoV-2 infection. Exposure to 2 suspected index cases (vs 1) significantly increased risk for both household/social contacts (relative risk [RR], 1.86) and healthcare workers (RR, 8.18). Increased contact time also increased risk for healthcare workers (3–12 hours: RR, 7.82, >12 hours: RR, 11.81, vs ≤2 hours), but not for household/social contacts. County incidence did not impact risk. Conclusions In our study, increased exposure to SARS-CoV-2 within household or healthcare settings led to higher risk of infection, but elevated community incidence did not. This reinforces the importance of interventions to decrease transmission in close contact settings.