COVID-19 pandemic lesson learned- critical parameters and research needs for UVC inactivation of viral aerosols.

The COVID-19 pandemic highlighted public awareness of airborne disease transmission in indoor settings and emphasized the need for reliable air disinfection technologies. This increased awareness will carry in the post-pandemic era along with the ever-emerging SARS-CoV variants, necessitating effective and well-defined protocols, methods, and devices for air disinfection. Ultraviolet (UV)-based air disinfection demonstrated promising results in inactivating viral bioaerosols. However, the reported data diversity on the required UVC doses has hindered determining the best UVC practices and led to confusion among the public and regulators. This article reviews available information on critical parameters influencing the efficacy of a UVC air disinfection system and, consequently, the required dose including the system's components as well as operational and environmental factors. There is a consensus in the literature that the interrelation of humidity and air temperature has a significant impact on the UVC susceptibility, which translate to changing the UVC efficacy of commercialized devices in indoor settings under varying conditions. Sampling and aerosolization techniques reported to have major influence on the result interpretation and it is recommended to use several sampling methods simultaneously to generate comparable and conclusive data. We also considered the safety concerns and the potential safe alternative of UVC, far-UVC. Finally, the gaps in each critical parameter and the future research needs of the field are represented. This paper is the first step to consolidating literature towards developing a standard validation protocol for UVC air disinfection devices which is determined as the one of the research needs.

COVID 19 vaccine distribution solution to the last mile challenge: Experimental and simulation studies of ultra-low temperature refrigeration system.

Most COVID-19 vaccines require ambient temperature control for transportation and storage. Both Pfizer and Moderna vaccines are based on mRNA and lipid nanoparticles requiring low temperature storage. The Pfizer vaccine requires ultra-low temperature storage (between -80 °C and -60 °C), while the Moderna vaccine requires -30 °C storage. Pfizer has designed a reusable package for transportation and storage that can keep the vaccine at the target temperature for 10 days. However, the last stage of distribution is quite challenging, especially for rural or suburban areas, where local towns, pharmacy chains and hospitals may not have the infrastructure required to store the vaccine. Also, the need for a large amount of ultra-low temperature refrigeration equipment in a short time period creates tremendous pressure on the equipment suppliers. In addition, there is limited data available to address ancillary challenges of the distribution framework for both transportation and storage stages. As such, there is a need for a quick, effective, secure, and safe solution to mitigate the challenges faced by vaccine distribution logistics. The study proposes an effective, secure, and safe ultra-low temperature refrigeration solution to resolve the vaccine distribution last mile challenge. The approach is to utilize commercially available products, such as refrigeration container units, and retrofit them to meet the vaccine storage temperature requirement. Both experimental and simulation studies are conducted to evaluate the technical merits of this solution with the ability to control temperature at -30 °C or -70 °C as part of the last mile supply chain for vaccine candidates.

Toxicology of alcohol-based hand rubs formulated with technical-grade ethanol.

Alcohol-based hand rubs (ABHRs) formulated with technical-grade ethanol were temporarily permitted in Canada and the U.S beginning April 2020 to meet the current demand due to COVID-19. ABHRs formulated with technical-grade ethanol are low risk for general use. In this review, we discuss the toxicity of common contaminants found in technical-grade ethanol, as well as contaminants that may have been introduced into the products during formulation and packaging of ABHRs. Although primary route of exposure is via dermal absorption and inhalation, there have been reported elevated concerns regarding to ingestion of ABHRs. Overall, the highest risks were associated with methanol (for its toxicity), ethyl acetate (skin defattening), and acetaldehyde (carcinogenic and teratogenic). For these reasons Health Canada and the United States Food and Drug Administration have issued recalls on products containing some of these contaminants. More vigilant policing by regulatory agencies and general product users are required to ensure compliance, safety, and efficacy of these new products, as demand continue to rise during this unprecedented pandemic.

A scoping review of surgical masks and N95 filtering facepiece respirators: Learning from the past to guide the future of dentistry.

With the 2019 emergence of coronavirus disease 19 (colloquially called COVID-19) came renewed public concern about airborne and aerosolized virus transmission. Accompanying this concern were many conflicting dialogues about which forms of personal protective equipment best protect dental health care practitioners and their patients from viral exposure. In this comprehensive review we provide a thorough and critical assessment of face masks and face shields, some of the most frequently recommended personal safeguards against viral infection. We begin by describing the function and practicality of the most common mask types used in dentistry: procedural masks, surgical masks, and filtering respirator facemasks (also called N95s). This is followed by a critical assessment of mask use based on a review of published evidence in three key domains: the degree to which each mask type is shown to protect against airborne and aerosolized disease, the reported likelihood for non-compliance among mask users, and risk factors associated with both proper and improper mask use. We use this information to conclude our review with several practical, evidence-based recommendations for mask use in dental and dental educational clinics.