ABSTRACT
OBJECTIVES: Prevention strategies implemented by hospitals to reduce nosocomial transmission of SARS-CoV-2 sometimes failed. Our aim was to determine the risk factors for nosocomial COVID-19. PATIENTS AND METHODS: A case-control study was conducted (September 1, 2020-January 31, 2021) with adult patients hospitalized in medical or surgical units. Infants or patients hospitalized in ICU were excluded. Cases were patients with nosocomial COVID-19 (clinical symptoms and RT-PCR + for SARS-CoV-2 or RT-PCR + for SARS-CoV-2 with Ct ≤ 28 more than 5 days after admission); controls were patients without infection (RT-PCR- for SARS-CoV-2 > 5 days after admission). They were matched according to length of stay before diagnosis and period of admission. Analyses were performed with a conditional logistic regression. RESULTS: A total of 281 cases and 441 controls were included. In the bivariate analysis, cases were older (OR per 10 years: 1.22; 95%CI [1.10;1.36]), had more often shared a room (OR: 1.74; 95%CI [1.25;2.43]) or a risk factor for severe COVID-19 (OR: 1.94; 95%CI [1.09;3.45]), were more often hospitalized in medical units [OR: 1.59; 95%CI [1.12;2.25]), had higher exposure to contagious health care workers (HCW; OR per 1person-day: 1.12; 95%CI [1.08;1.17]) and patients (OR per 1 person-day: 1.11; 95%CI [1.08;1.14]) than controls. In an adjusted model, risk factors for nosocomial COVID-19 were exposure to contagious HCW (aOR per 1person-day: 1.08; 95%CI [1.03;1.14]) and to contagious patients (aOR per 1person-day: 1.10; 95%CI [1.07;1.13]). CONCLUSIONS: Exposure to contagious professionals and patients are the main risk factors for nosocomial COVID-19.
ABSTRACT
Introduction: During the COVID-19 pandemic, hospitals implemented infection prevention strategies to reduce nosocomial transmission. Nevertheless, these strategies sometimes failed and determination of risk factors of transmission is crucial. Objectives: Our main objective was to determine the risk factors of nosocomial Covid-19 at Grenoble Alpes University hospital (CHUGA). Methods: A case-control study was conducted at CHUGA. A retrospective data collection was performed between 01/09/2020 and 31/01/2021. Adults patients hospitalized in medicine or surgery units were included. Infants or patients hospitalized in ICU were excluded. Case patients were patients with a nosocomial Covid-19 (clinical symptoms and positive PCR for SARS-CoV-2 or positive PCR for SARSCoV- 2 ≤ 28CT);control patients were patients without infection (negative PCR for SARS-CoV-2). They were matched by their length of stay and their period of admission. Bivariate and multivariate analysis were performed with a conditional logistic regression by Stata 12.0. Results: A total of 1393 patients with Covid-19 were hospitalized;722 patients were included in the case-control analysis ( ncase = 281;ncontrol = 441). In bivariate analysis, case patients were significantly older (OR:1.25;CI95% [1.12;1.40]), had more often a roommate (OR:1.74;CI95% [1.23;2.43]), more often a co-infection (OR:1.73;CI95% [1.26;2.36]), more often a severity risk factor of Covid-19 (OR:2.06;CI95% [1.14;3.71]) and a higher Charlson comorbidity index (OR:1,09;CI95% [1,01;1,20] than control patients. In an adjusted model that included the admission in the emergency room and the existence of a severity risk factor, the risk factors of nosocomial Covid-19 were: older age (aOR:1.24 per 10 years;CI95% [1.08;4.41]), having a roommate (aOR:1.63;CI95% [1.14;2.33]), and having a co-infection (aOR:1.62;CI95% [1.17;2.26]). Conclusion: Older patients with co-infection hospitalized in a multiple room were more susceptible to nosocomial Covid-19. These preliminary results need to be consolidated taking into account exposition to contagious healthcare workers or contagious patients.