Researchers say that few studies have assessed whether the increased SARS-CoV-2 risk of healthcare workers (HCWs) is carried on to their household contacts. Within a prospective HCW cohort, Kohler, et al. (2023) assessed the SARS-CoV-2 risk of household contacts of HCWs depending on the HCWs cumulative exposure to COVID-19 patients and identified factors influencing this association.

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

Of 2406 HCWs, 466 (19%) reported ≥ 1 SARS-CoV-2 positive household. In multivariable analysis, patient exposure of HCWs (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 HCWs 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 HCWs, delayed first vaccination was associated with increased household SARS-CoV-2 positivity (aOR 1.14 per month, 95% CI 1.08–1.21).

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 HCWs might indirectly reduce the infection risk of their households.

Reference: Kohler P, et al. SARS-CoV-2 risk in household contacts of healthcare workers: a prospective cohort study. Antimicrobial Resistance & Infection Control. Vol. 12, article number 98 (2023).