High Level Bioaerosol Protection against Infective Aerosols: How Medical Face Masks Compare against Respirators.

Face masks and respirators are commonly used to prevent the transmission of infectious diseases that spread by respiratory droplets and aerosols. However, there is still uncertainty about the protective effect of the different types of masks against virus containing aerosols. To determine the as-worn bioaerosol protection efficacy of different face coverings and estimate the possible protective function against airborne diseases, we challenged different respirators and medical masks on a standardized dummy head with a bioaerosol containing MS2 bacteriophages as virus surrogates. In our experiments, FFP2 respirators showed the highest filtration efficacy 94 ± 4 (SD) % followed by medical masks 93 ± 3 (SD) % and KN95 respirators 90 ± 7 (SD) %. Nevertheless, we found no statistically significant difference between respirators and medical masks in terms of provided protection against infective aerosols. Our findings indicate that both respirators and medical masks provide a high as-worn bioaerosol protection efficacy against virus containing aerosols, and therefore, a very high protection against airborne diseases. Considering the higher comfort, better availability, and lower price of medical masks in contrast to respirators, it is recommendable to use medical face masks especially in low risk situations and in general public.

Efficiency analysis of rapid antigen test based SARS-CoV-2 in hospital contact tracing and screening regime: test characteristics and cost effectiveness.

In the context of the current SARS-CoV-2 pandemic, reliable and cost-efficient screening and testing strategies are crucial to prevent disease transmission and reduce socioeconomic losses. To assess the efficiency of a rapid antigen test (RAT)-based SARS-CoV-2 contact-tracing and screening regime, we conducted a retrospective analysis of RAT and polymerase chain reaction (PCR) test data over a 1-year period, assessed test characteristics and estimated cost-effectiveness. The RAT had a sensitivity of 70.2% overall and 89.3% for people with a high risk of infectivity. We estimated inpatient treatment and quarantined healthcare worker costs of over € 5860.83, whereas the cost of identifying one SARS-CoV-2 positive person by RAT for our patient cohort was € 1210.75. In contrast, the estimated respective PCR cost was € 5043.32. Therefore, a RAT-based contract tracing and screening regime may be an efficient and cost-effective way to contribute to the early identification and prevention of SARS-CoV-2 transmission.

Development of a web-based contact tracing and point-of-care-testing workflow for SARS-CoV-2 at a German University Hospital.

INTRODUCTION: In late 2019, a novel coronavirus was detected in China. Supported by its respiratory transmissibility, even by people infected without symptomatic disease, this coronavirus soon began to rapidly spread worldwide. BACKGROUND: Many countries have implemented different infection control and containment strategies due to ongoing community transmission. In this context, contact tracing as well as adequate testing and consequent quarantining of high-risk contacts play leading roles in containing the virus by interrupting infection chains. This approach is especially important in the hospital setting where contacts often cannot be avoided and physical distance is usually not possible. Furthermore, health care workers (HCWs) usually have contact with a variety of vulnerable people, making it essential to identify infections among hospital employees as soon as possible to interrupt the rapid spread of SARS-CoV-2 in the facility. Several electronic tools for contact tracing, such as specific software or mobile phone apps, are available for the public health sector. In contrast, contact tracing in hospitals often has to be carried out without helpful electronic tools, and an enormous amount of human resources is typically required. AIM: For rapid contact tracing and effective infection control and management measures for HCWs in hospitals, adapted technical solutions are needed. METHODS: In this study, we report the development of our containment strategy to a web-based contact tracing and rapid point-of-care-testing workflow. RESULTS/CONCLUSION: Our workflow yielded efficient control of the rapidly evolving situation during the SARS-CoV-2 pandemic from May 2020 until January 2021 at a German University Hospital.

Development and Validation of a Life-Sized Mock Circulatory Loop of the Human Circulation for Fluid-Mechanical Studies.

Mock circulatory loops (MCLs) are usually developed for assessment of ventricular assist devices and consist of abstracted anatomical structures represented by connecting tubing pipes and controllable actuators which could mimic oscillating flow processes. However, with increasing use of short-term peripheral mechanical support (extracorporeal life support [ECLS]) and the upcoming evidence of even counteracting flow processes between the failing native circulation and ECLS, MCLs incorporating the peripheral vascular system and preserved anatomical structures are becoming more important for systematic assessment of these processes. For reproducible and standardized fluid-mechanical studies using magnetic resonance imaging, Doppler ultrasound, and computational fluid dynamics measurements, we developed a MCL of the human circulation. Silicon-based life-sized dummies of the human aorta and vena cava (vascular module) were driven by paracorporeal pneumatic assist devices. The vascular module is placed in a housing with all arterial branches merging into peripheral resistance and compliances modules, and blood-mimicking fluid returns to the heart module through the venous dummy. Compliance and resistance chambers provide for an adequate simulation of the capillary system. Extracorporeal life support cannulation can be performed in the femoral and subclavian arteries and in the femoral and jugular veins. After adjusting vessel diameters using variable Hoffmann clamps, physiologic flow rates were achieved in the supraaortic branches, the renal and mesenteric arteries, and the limb arteries with physiologic blood pressure and cardiac output (4 L/min). This MCL provides a virtually physiologic platform beyond conventional abstracted MCLs for simulation of flow interactions between the human circulation and external circulation generated by ECLS.