ABSTRACT
BackgroundCOVID-19 has resulted in many infections in healthcare workers (HCWs) globally. We performed state-wide SARS-CoV-2 genomic epidemiological investigations to identify HCW transmission dynamics and provide recommendations to optimise healthcare system preparedness for future outbreaks. MethodsGenome sequencing was attempted on all COVID-19 cases in Victoria, Australia. We combined genomic and epidemiologic data to investigate the source of HCW infections across multiple healthcare facilities (HCFs) in the state. Phylogenetic analysis and fine-scale hierarchical clustering were performed for the entire Victorian dataset including community and healthcare cases. Facilities provided standardised epidemiological data and putative transmission links. FindingsBetween March and October 2020, approximately 1,240 HCW COVID-19 infection cases were identified; 765 are included here. Genomic sequencing was successful for 612 (80%) cases. Thirty-six investigations were undertaken across 12 HCFs. Genomic analysis revealed that multiple introductions of COVID-19 into facilities (31/36) were more common than single introductions (5/36). Major contributors to HCW acquisitions included mobility of staff and patients between wards and facilities, and characteristics and behaviours of individual patients including super-spreading events. Key limitations at the HCF level were identified. InterpretationGenomic epidemiological analyses enhanced understanding of HCW infections, revealing unsuspected clusters and transmission networks. Combined analysis of all HCWs and patients in a HCF should be conducted, supported by high rates of sequencing coverage for all cases in the population. Established systems for integrated genomic epidemiological investigations in healthcare settings will improve HCW safety in future pandemics. FundingThe Victorian Government, the National Health and Medical Research Council Australia, and the Medical Research Future Fund.
ABSTRACT
ObjectiveTo assess the effectiveness of aerosol filtration by portable air cleaning devices with high efficiency particulate air (HEPA) filters used in addition to standard building heating ventilation and air-conditioning (HVAC). MethodsTest rooms, including a hospital single-patient room, were filled with test aerosol to simulate aerosol movement. Aerosol counts were measured over time with various portable air cleaning devices and room ventilation systems to quantify the aerosol concentration reduction rate and overall clearance rate. ResultsPortable air cleaners were very effective in removing aerosols, especially for the devices with high flow rate. In a small control room, the aerosols were cleared 4 to 5 times faster with portable air cleaners than the room with HVAC alone. A single bed hospital room equipped with an excellent ventilation rate ([~] 14 air changes per hour) can clear the aerosols in 20 minutes. However, with the addition of two air cleaners, the clearance time became 3 times faster (in 6 minutes and 30 seconds). ConclusionsPortable air cleaning devices with HEPA filtration were highly effective at removing aerosols. To clear aerosols (above 90% clearance) in under 10 minutes requires around 25 air changes per hour; readily feasible with air cleaners. Inexpensive portable air cleaning devices should be considered for small and enclosed spaces in health care settings such as inpatient rooms, personal protective equipment donning/doffing stations, and staff tea rooms. Portable air cleaners are particularly important where there is limited ability to reduce aerosol transmission with building HVAC ventilation.
ABSTRACT
ObjectiveTo study the airflow, transmission and clearance of aerosols in the clinical spaces of a hospital ward that had been used to care for patients with COVID-19, and to examine the impact of portable air cleaners on aerosol clearance. DesignObservational study SettingA single ward of a tertiary public hospital in Melbourne Australia InterventionGlycerine-based aerosol was used as a surrogate for respiratory aerosols. The transmission of aerosols from a single patient room into corridors and a nurses station in the ward was measured. The rate of clearance of aerosols was measured over time from the patient room, nurses station and ward corridors with and without air cleaners (also called portable HEPA filters). ResultsAerosols rapidly travelled from the patient room into other parts of the ward. Air cleaners were effective in increasing the clearance of aerosols from the air in clinical spaces and reducing their spread to other areas. With two small domestic air cleaners in a single patient room of a hospital ward, 99% of aerosols could be cleared within 5.5 minutes. ConclusionAir cleaners may be useful in clinical spaces to help reduce the risk of healthcare acquired acquisition of respiratory viruses that are transmitted via aerosols. They are easy to deploy and are likely to be cost effective in a variety of healthcare settings
ABSTRACT
BackgroundHealthcare workers have frequently become infected with SARS-CoV-2 whilst treating patients with COVID-19. A variety of novel devices have been proposed to reduce COVID-19 cross contamination. ObjectiveTo test whether a novel patient isolation hood was safe and comfortable, and could potentially reduce HCW COVID-19 infections. MethodsProspective cohort study of 20 patients, entailing staff/patient questionnaires, and safety aspects of prototype isolation hoods.Prospective collection of HCW COVID-19 data.Assessment of the hoods safety and practicality, and adverse event reporting. Outcome MeasuresQuestionnaires responses, adverse events reporting, rates of HCW infections during study period (20/6/2020 -21/7/2020).HCW COVID-19 infections reported until last recorded HCW COVID-19 diagnosis (20/6/2020 -27/9/2020). ResultsOf the 60 (of 64) eligible individual staff surveys, 60 favoured isolation hood use.Staff were unanimous in: perceiving the hood as safe (60/60), preferring its use (56/56), and understanding its potential COVID-19 cross-contamination minimisation (60/60). All eight patients who completed the questionnaire thought the isolation hood helped prevent COVID-19 cross-infection, was safe, and comfortable. There were no reported patient safety adverse events. The overall attack COVID-19 attack rate from 20/6/2020-27/9/2020 among registered nurses was 3.4% (102/2994): ICUs 2.2% (3/138), Geriatric wards 13.2% (26/197), and COVID-19 Wards 18.3% (32/175). The COVID-19 attack rate among medical staff was: all junior medical staff 2.1% (24/932), senior medical staff 0.7% (4/607), aged care/rehabilitation 6.7% (2/30), and ICU all medical staff 8.6% (3/35). ConclusionsThe isolation hood was strongly endorsed by staff and patients, and post-study became part of standard ICU therapy. ICU nurse COVID-19 infection rates were low. ICU HCWs feel safer when treating patients with COVID-19 using an isolation hood.
