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Predictors of SARS-CoV-2 infection following high-risk exposure: a test-negative design case-control study
Kristin L. Andrejko; Jake Pry; Jennifer F. Myers; John Openshaw; James Watt; Nozomi Birkett; Jennifer L DeGuzman; Sophia S. Li; Camilla M. Barbaduomo; Anna T. Fang; Vivian H. Tran; Mahsa H. Javadi; Paulina M. Frost; Zheng N. Dong; Seema Jain; Joseph A. Lewnard.
  • Kristin L. Andrejko; University of California at Berkeley
  • Jake Pry; California Department of Public Health
  • Jennifer F. Myers; California Department of Public Health
  • John Openshaw; California Department of Public Health
  • James Watt; California Department of Public Health
  • Nozomi Birkett; California Department of Public Health
  • Jennifer L DeGuzman; California Department of Public Health
  • Sophia S. Li; California Department of Public Health
  • Camilla M. Barbaduomo; California Department of Public Health
  • Anna T. Fang; California Department of Public Health
  • Vivian H. Tran; California Department of Public Health
  • Mahsa H. Javadi; California Department of Public Health
  • Paulina M. Frost; California Department of Public Health
  • Zheng N. Dong; California Department of Public Health
  • Seema Jain; California Department of Public Health
  • Joseph A. Lewnard; University of California Berkeley
Preprint Dans Anglais | medRxiv | ID: ppmedrxiv-21265295
ABSTRACT
BackgroundNon-pharmaceutical interventions (NPIs) are recommended for COVID-19 mitigation. However, the effectiveness of NPIs in preventing SARS-CoV-2 transmission remains poorly quantified. MethodsWe conducted a test-negative design case-control study enrolling cases (testing positive for SARS-CoV-2) and controls (testing negative) with molecular SARS-CoV-2 diagnostic test results reported to California Department of Public Health between 24 February-26 September, 2021. We used conditional logistic regression to assess predictors of case status among participants who reported contact with an individual known or suspected to have been infected with SARS-CoV-2 ("high-risk exposure") within [≤]14 days of testing. Results643 of 1280 cases (50.2%) and 204 of 1263 controls (16.2%) reported high-risk exposures [≤]14 days before testing. Adjusted odds of case status were 2.94-fold (95% confidence interval 1.66-5.25) higher when high-risk exposures occurred with household members (vs. other contacts), 2.06-fold (1.03-4.21) higher when exposures occurred indoors (vs. not indoors), and 2.58-fold (1.50-4.49) higher when exposures lasted [≥]3 hours (vs. shorter durations) among unvaccinated and partially-vaccinated individuals; excess risk associated with such exposures was mitigated among fully-vaccinated individuals. Mask usage by participants or their contacts during high-risk exposures reduced adjusted odds of case status by 48% (8-72%). Adjusted odds of case status were 68% (32-84%) and 77% (59-87%) lower for partially- and fully-vaccinated participants, respectively, than for unvaccinated participants. Benefits of mask usage were greatest when exposures lasted [≥]3 hours, occurred indoors, or involved non-household contacts. ConclusionsNPIs reduced the likelihood of SARS-CoV-2 infection following high-risk exposure. Vaccine effectiveness was substantial for partially and fully vaccinated persons. KEY POINTSO_LISARS-CoV-2 infection risk was greatest for unvaccinated participants when exposures to known or suspected cases occurred indoors or lasted [≥]3 hours. C_LIO_LIFace mask usage when participants were exposed to a known or suspect case reduced odds of infection by 48%. C_LI
Texte intégral: Disponible Collection: Preprints Base de données: medRxiv Type d'étude: Etude d'étiologie / Étude observationnelle / Étude pronostique / Facteurs de risque Les sujets: Vaccins langue: Anglais Année: 2021 Type de document: Preprint

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Texte intégral: Disponible Collection: Preprints Base de données: medRxiv Type d'étude: Etude d'étiologie / Étude observationnelle / Étude pronostique / Facteurs de risque Les sujets: Vaccins langue: Anglais Année: 2021 Type de document: Preprint