Transmission risk of respiratory viruses in natural and mechanical ventilation environments: implications for SARS-CoV-2 transmission in Africa

Exposure to ambient air pollutants is associated with an increased incidence of hyperuricemia: A longitudinal cohort study among Chinese government employees

BACKGROUND

It is widely recognized that ambient air pollution can induce various detrimental health outcomes. However, evidence linking ambient air pollutants and hyperuricemia incidence is scarce.

OBJECTIVES

To assess the association between long-term air pollution exposure and the risk of hyperuricemia.

METHODS

In this study, a total of 5854 government employees without hyperuricemia were recruited and followed up from January 2018 to June 2021 in Hunan Province, China. Hyperuricemia was defined as serum uric acid (SUA) level of >420 μmol/L for men and >360 μmol/L for women or use of SUA-lowering medication or diagnosed as hyperuricemia during follow-up. Data from local air quality monitoring stations were used to calculate individual exposure levels of PM10, PM2.5, SO2 and NO2 by inverse distance weightingn (IDW) method. Cox proportional hazard model was applied to evaluate the causal relationships between air pollutant exposures and the risk of hyperuricemia occurrence after adjustment for potential confounders and meanwhile, restricted cubic spline was used to explore the dose-response relationships.

RESULTS

The results indicated that exposures to PM10 (hazard ratio, HR = 1.042, 95% conficence interal, 95% CI: 1.028, 1.057), PM2.5 (HR = 1.204, 95% CI: 1.141, 1.271) and NO2 (HR = 1.178, 95% CI: 1.125,1.233) were associated with an increased HR of hyperuricemia. In addition, a nonlinear dose-response relationship was found between PM10 exposure level and the HR of hyperuricemia (p for nonlinearity = 0.158) with a potential threshold of 50.11 μg/m3. Subgroup analysis demonstrated that participants usually waking up at night and using natural ventilation were more vulnerable to the exposures of PM10, PM2.5, NO2, and SO2.

CONCLUSION

Long-term exposures to ambient PM10, PM2.5 and NO2 are associated with an increased incidence of hyperuricemia among Chinese government employees.

Implemented indoor airborne transmission mitigation strategies during COVID-19: a systematic review

The COVID-19 pandemic has inflicted major economic and health burdens across the world. On the other hand, the potential airborne transmission of SARS-COV-2 via air can deeply undermine the effectiveness of countermeasures against spreading the disease. Therefore, there is an intense focus to look for ways to mitigate the COVID-19 spread within various indoor settings. This work systematically reviewed articles regarding airborne transmission of SARS-COV2 in various indoor settings since the onset of the pandemic. The systematic search was performed in Scopus, Web of Science, and PubMed databases and has returned 19 original articles carefully screened with regard to inclusion and exclusion criteria. The results showed that the facilities, such as dormitories and classrooms, received the most attention followed by office buildings, healthcare facilities, residential buildings, and other potential enclosed spaces such as a metro wagon. Besides, the majority of the studies were conducted experimentally while other studies were done using computer simulations. United States (n = 5), Spain (n = 4) and China (n = 3) were the top three countries based on the number of performed research. Ventilation rate was the most influential parameter in controlling the infection spread. CO₂ was the primary reference for viral spread in the buildings. The use of natural ventilation or a combination of mechanical and natural ventilations was found to be highly effective in the studies. The current work helps in furthering research on effective interventions to improve indoor air quality and control the spread of COVID-19 and other respiratory diseases.

Supplementary information

The online version contains supplementary material available at 10.1007/s40201-023-00847-0.

A continent-wide effort and solidarity at curbing COVID-19 pandemic: the Africa task force for novel coronavirus (AFTCOR) infection prevention and control technical working group's experience

A continent-wide Africa Task Force for Coronavirus with its six technical working groups was formed to prepare adequately and respond to the novel Coronavirus disease (COVID-19) outbreak in Africa. This research in practice article aimed to describe how the infection prevention and control (IPC) technical working group (TWG) supported Africa Centre for Disease Control and Prevention (Africa CDC) in preparedness and response to COVID-19 on the continent. To effectively address the multifaceted IPC TWG mandate of organizing training and implementing rigorous IPC measures at healthcare service delivery points, the working group was sub-divided into four sub-groups-Guidelines, Training, Research, and Logistics. The action framework was used to describe the experiences of each subgroup. The guidelines subgroup developed 14 guidance documents and two advisories; all of which were published in English. In addition, five of these documents were translated and published in Arabic, while three others were translated and published in French and Portuguese. Challenges faced in the guidelines subgroup included the primary development of the Africa CDC website in English, and the need to revise previously issued guidelines. The training subgroup engaged the Infection Control Africa Network as technical experts to carry out in-person training of IPC focal persons and port health personnel across the African continent. Challenges faced included the difficulty in conducting face-to-face IPC training and onsite technical support due to the lockdown. The research subgroup developed an interactive COVID-19 Research Tracker on the Africa CDC website and conducted a context-based operation and implementation research. The lack of understanding of Africa CDC's capacity to lead her own research was the major challenge faced by the research subgroup. The logistics subgroup assisted African Union (AU) member states to identify their IPC supply needs through capacity building for IPC quantification. A notable challenge faced by the logistics subgroup was the initial lack of experts on IPC logistics and quantifications, which was later addressed by the recruitment of professionals. In conclusion, IPC cannot be built overnight nor can it be promoted abruptly during outbreaks of diseases. Thus, the Africa CDC should build strong national IPC programmes and support such programmes with trained and competent professionals.

Airborne and aerosol pathogen transmission modeling of respiratory events in buildings: An overview of computational fluid dynamics

Pathogen droplets released from respiratory events are the primary means of dispersion and transmission of the recent pandemic of COVID-19. Computational fluid dynamics (CFD) has been widely employed as a fast, reliable, and inexpensive technique to support decision-making and to envisage mitigatory protocols. Nonetheless, the airborne pathogen droplet CFD modeling encounters limitations due to the oversimplification of involved physics and the intensive computational demand. Moreover, uncertainties in the collected clinical data required to simulate airborne and aerosol transport such as droplets' initial velocities, tempo-spatial profiles, release angle, and size distributions are broadly reported in the literature. There is a noticeable inconsistency around these collected data amongst many reported studies. This study aims to review the capabilities and limitations associated with CFD modeling. Setting the CFD models needs experimental data of respiratory flows such as velocity, particle size, and number distribution. Therefore, this paper briefly reviews the experimental techniques used to measure the characteristics of airborne pathogen droplet transmissions together with their limitations and reported uncertainties. The relevant clinical data related to pathogen transmission needed for postprocessing of CFD data and translating them to safety measures are also reviewed. Eventually, the uncertainty and inconsistency of the existing clinical data available for airborne pathogen CFD analysis are scurtinized to pave a pathway toward future studies ensuing these identified gaps and limitations.

Evolving changes in mortality of 13,301 critically ill adult patients with COVID-19 over 8 months

PURPOSE

Clinical characteristics and management of COVID-19 patients have evolved during the pandemic, potentially changing their outcomes. We analyzed the associations of changes in mortality rates with clinical profiles and respiratory support strategies in COVID-19 critically ill patients.

METHODS

A multicenter cohort of RT-PCR-confirmed COVID-19 patients admitted at 126 Brazilian intensive care units between February 27^th and October 28^th, 2020. Assessing temporal changes in deaths, we identified distinct time periods. We evaluated the association of characteristics and respiratory support strategies with 60-day in-hospital mortality using random-effects multivariable Cox regression with inverse probability weighting.

RESULTS

Among the 13,301 confirmed-COVID-19 patients, 60-day in-hospital mortality was 13%. Across four time periods identified, younger patients were progressively more common, non-invasive respiratory support was increasingly used, and the 60-day in-hospital mortality decreased in the last two periods. 4188 patients received advanced respiratory support (non-invasive or invasive), from which 42% underwent only invasive mechanical ventilation, 37% only non-invasive respiratory support and 21% failed non-invasive support and were intubated. After adjusting for organ dysfunction scores and premorbid conditions, we found that younger age, absence of frailty and the use of non-invasive respiratory support (NIRS) as first support strategy were independently associated with improved survival (hazard ratio for NIRS first [95% confidence interval], 0.59 [0.54-0.65], p < 0.001).

CONCLUSION

Age and mortality rates have declined over the first 8 months of the pandemic. The use of NIRS as the first respiratory support measure was associated with survival, but causal inference is limited by the observational nature of our data.