The Synergistic Effect of Time of Exposure, Distance and No Use of Personal Protective Equipment in the Determination of SARS-CoV-2 Infection: Results of a Contact Tracing Follow-Up Study in Healthcare Workers

International Journal of Environmental Research and Public Health

on behalf of Collaborative Group Sapienza¹  Fortunata Vasaturo²  Giuseppe La Torre³  Elena Mazzalai³  Ferdinando Romano³  Claudio Maria Mastroianni³  Mattia Marte³  Barbara Dorelli³  Caterina Fimiani³  Vittoria Cammalleri³  Filippo Picchioni³  Marta Chiappetta³  Augusto Faticoni³  Shizuka Kibi³  Roberta Noemi Pocino³  Daniela Marotta³  Anna Paola Massetti³  Carlo Maria Previte³  Lavinia Camilla Barone³  Vanessa India Barletta³  Monica Giffi³  Alberto Deales⁴  Guido Antonelli⁵  Ombretta Turriziani⁵ 

[1] ;Clinica Medica Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, 00185 Roma, Italy;Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Roma, Italy;Health Direction, Teaching Hospital Policlinico Umberto I, 00161 Roma, Italy;Laboratory of Virology, Department of Molecular Medicine, Sapienza University of Rome, 00185 Roma, Italy;

关键词: SARS-CoV-2;    COVID-19;    contact tracing;    safety;    synergism;    personal protective equipment;   

DOI  :  10.3390/ijerph18189456

来源: DOAJ

【 摘 要 】

The aim of this study is to assess the effect of contact time, contact distance and the use of personal protective equipment on the determination of SARS-CoV-2 infection in healthcare workers (HCWs). This study consists of an analysis of data gathered for safety reasons at the Sapienza Teaching Hospital Policlinico Umberto I in Rome through the surveillance system that was put into place after the worsening of the COVID-19 pandemic. The studied subjects consist of HCWs who were put under health surveillance, i.e., all employees who were in contact with subjects who were confirmed to have tested positive for SARS-CoV-2. The HCWs under surveillance were monitored for a period encompassing ten days after the date of contact, during which they undertook nasopharyngeal swab tests analysed through RT-PCR (RealStar® SARS-CoV-2 Altona Diagnostic–Germany). Descriptive and univariate analyses have been undertaken, considering the following as risk factors: (a) no personal protective equipment use (PPE); (b) Distance < 1 m between the positive and contact persons; (c) contact time > 15′. Finally, a Cox regression and an analysis of the level of synergism between factors, as specified by Rothman, were carried out. We analysed data from 1273 HCWs. Of these HCWs, 799 (62.8%) were females, with a sample average age of 47.8 years. Thirty-nine (3.1%) tested positive during surveillance. The overall incidence rate was 0.4 per 100 person-days. Time elapsed from the last exposure and a positive RT-PCR result ranged from 2 to 17 days (mean = 7, median = 6 days). In the univariate analysis, a distance <1 m and a contact time > 15′ proved to be risk factors for the SARS-CoV-2 infection, with a hazard ratio (HR) of 2.62 (95% CI: 1.11–6.19) and 3.59 (95% IC: 1.57–8.21), respectively. The synergism analysis found the highest synergism between the “no PPE use” x “Contact time”. The synergy index S remains strongly positive also in the analysis of the factors “no PPE use” x “Distance” and “Time of contact” x “Distance”. This study confirms the absolute need to implement safety protocols during the pandemic and to use the correct PPE within health facilities in order to prevent SARS-CoV-2 infection. The analysis shows that among the factors considered (contact time and distance, no use of PPE), there is a strong synergistic effect.

【 授权许可】

Unknown