Respiratory transmission of SARS-CoV-2 from one older patient to another by airborne mechanisms in hospital and nursing home settings represents an important health challenge during the COVID-19 pandemic. However, the factors that influence the concentration of respiratory droplets and aerosols that potentially contribute to hospital- and nursing care-associated transmission of SARS-CoV-2 are not well understood. To assess the effect of health care professional (HCP) and patient activity on size and concentration of airborne particles, an optical particle counter was placed (for 24 h) in the head position of an empty bed in the hospital room of a patient admitted from the nursing home with confirmed COVID-19. The type and duration of the activity, as well as the number of HCPs providing patient care, were recorded. Concentration changes associated with specific activities were determined, and airway deposition modeling was performed using these data. Thirty-one activities were recorded, and six representative ones were selected for deposition modeling, including patient’s activities (coughing, movements, etc.), diagnostic and therapeutic interventions (e.g., diagnostic tests and drug administration), as well as nursing patient care (e.g., bedding and hygiene). The increase in particle concentration of all sizes was sensitive to the type of activity. Increases in supermicron particle concentration were associated with the number of HCPs (r = 0.66; p < 0.05) and the duration of activity (r = 0.82; p < 0.05), while submicron particles increased with all activities, mainly during the daytime. Based on simulations, the number of particles deposited in unit time was the highest in the acinar region, while deposition density rate (number/cm²/min) was the highest in the upper airways. In conclusion, even short periods of HCP-patient interaction and minimal patient activity in a hospital room or nursing home bedroom may significantly increase the concentration of submicron particles mainly depositing in the acinar regions, while mainly nursing activities increase the concentration of supermicron particles depositing in larger airways of the adjacent bed patient. Our data emphasize the need for effective interventions to limit hospital- and nursing care-associated transmission of SARS-CoV-2 and other respiratory pathogens (including viral pathogens, such as rhinoviruses, respiratory syncytial virus, influenza virus, parainfluenza virus and adenoviruses, and bacterial and fungal pathogens).

SARS-CoV-2 通过医院和疗养院环境中的空气传播机制从一名老年患者呼吸道传播到另一名老年患者，这是 COVID-19 大流行期间的一项重要健康挑战。然而，影响呼吸道飞沫和气溶胶浓度的因素尚不清楚，而这些因素可能导致医院和护理相关的 SARS-CoV-2 传播。为了评估医疗保健专业人员 (HCP) 和患者活动对空气中颗粒大小和浓度的影响，将光学颗粒计数器放置在一名从 2017 年 1 月 1 日入院的患者病房空床的头部位置（持续 24 小时）。确诊患有 COVID-19 的疗养院。记录活动的类型和持续时间，以及提供患者护理的 HCP 数量。确定与特定活动相关的浓度变化，并使用这些数据进行气道沉积建模。记录了三十一项活动，并选择六项有代表性的活动进行沉积建模，包括患者的活动（咳嗽、运动等）、诊断和治疗干预（例如诊断测试和药物管理）以及护理患者护理（例如，床上用品和卫生）。所有尺寸的颗粒浓度的增加对活动类型敏感。超微米颗粒浓度的增加与 HCP 数量 ( r = 0.66; p < 0.05) 和活动持续时间 ( r = 0.82; p < 0.05) 相关，而亚微米颗粒随着所有活动的增加而增加，主要是在白天。 模拟结果显示，单位时间内沉积的颗粒数量在腺泡区最高，沉积密度率（个/cm ² /min）在上呼吸道最高。总之，即使是短期的 HCP 与患者互动以及患者在医院病房或疗养院卧室中的最小活动也可能显着增加主要沉积在腺泡区域的亚微米颗粒的浓度，而主要是护理活动会增加沉积在腺泡区域的超微米颗粒的浓度。邻床患者的气道较大。我们的数据强调需要采取有效的干预措施，限制与医院和护理相关的 SARS-CoV-2 和其他呼吸道病原体（包括病毒病原体，如鼻病毒、呼吸道合胞病毒、流感病毒、副流感病毒和腺病毒）的传播细菌和真菌病原体）。