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. 2023 Sep 8;12(1):98.
doi: 10.1186/s13756-023-01300-5.

SARS-CoV-2 risk in household contacts of healthcare workers: a prospective cohort study

Philipp Kohler  1 , Tamara Dörr  2 , Andrée Friedl  3 , Reto Stocker  4 , Danielle Vuichard  5   6 , Stefan P Kuster  2 , Christian R Kahlert  2   7 ; SURPRISE Study Group
Collaborators, Affiliations

SARS-CoV-2 risk in household contacts of healthcare workers: a prospective cohort study

Philipp Kohler et al. Antimicrob Resist Infect Control. .

Abstract

Background: Few studies have assessed whether the increased SARS-CoV-2 risk of healthcare workers (HCW) is carried on to their household contacts. Within a prospective HCW cohort, we assessed the SARS-CoV-2 risk of household contacts of HCW depending on the HCWs cumulative exposure to COVID-19 patients and identified factors influencing this association.

Methods: HCW aged ≥ 16 years from nine Swiss healthcare networks participated. HCW without any household contacts were excluded. For HCW, cumulative patient exposure (number of COVID-19 patient contacts times average contact duration during a 12-month follow-up) was calculated. During follow-up, HCW reported SARS-CoV-2 nasopharyngeal swab results and positive swab results of their household contacts. We used multivariable logistic regression to identify variables associated with SARS-CoV-2 household positivity.

Results: Of 2406 HCW, 466 (19%) reported ≥ 1 SARS-CoV-2 positive household. In multivariable analysis, patient exposure of HCW (adjusted OR [aOR] 1.08 per category, 95% CI 1.04-1.12), household size (aOR 1.53 per household member, 95% CI 1.35-1.73) and having children (aOR 0.70, 95% CI 0.53-0.94) remained associated with household positivity. Vaccinated HCW had a lower risk (aOR 0.54, 95% CI 0.38-0.77) of reporting a positive contact, as were those using respirator masks in contact with COVID-19 patients (aOR 0.65, 95% CI 0.49-0.86). Among vaccinated HCW, delayed first vaccination was associated with increased household SARS-CoV-2 positivity (aOR 1.14 per month, 95% CI 1.08-1.21).

Conclusions: SARS-CoV-2 positivity in household contacts of HCW increases with higher cumulative COVID-19 patient exposure of HCWs. Measures reducing the SARS-CoV-2 risk in HCW might indirectly reduce the infection risk of their households.

Keywords: COVID-19; Healthcare workers; Household contacts; SARS-CoV-2; Spillover.

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Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Fig. 1
Fig. 1
SARS-CoV-2-positivity in household contacts and in corresponding index healthcare workers by cumulative patient exposure. SARS-CoV-2 positivity in household contacts (red) and in corresponding index healthcare workers (grey), depending on cumulative patient exposure of healthcare workers. Black lines show graphs of linear regression analysis; shaded areas correspond to 95% confidence intervals
See this image and copyright information in PMC

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