Respiratory Infectious Diseases Research Articles

Repetition in social contacts: implications in modelling the transmission of respiratory infectious diseases in pre-pandemic and pandemic settings.

The spread of viral respiratory infections is intricately linked to human interactions, and this relationship can be characterized and modelled using social contact data. However, many analyses tend to overlook the recurrent nature of these contacts. To bridge this gap, we undertake the task of describing individuals' contact patterns over time by characterizing the interactions made with distinct individuals during a week. Moreover, we gauge the implications of this temporal reconstruction on disease transmission by juxtaposing it with the assumption of random mixing over time. This involves the development of an age-structured individual-based model, using social contact data from a pre-pandemic scenario (the POLYMOD study) and a pandemic setting (the Belgian CoMix study), respectively. We found that accounting for the frequency of contacts impacts the number of new, distinct, contacts, revealing a lower total count than a naive approach, where contact repetition is neglected. As a consequence, failing to account for the repetition of contacts can result in an underestimation of the transmission probability given a contact, potentially leading to inaccurate conclusions when using mathematical models for disease control. We, therefore, underscore the necessity of acknowledging contact repetition when formulating effective public health strategies.

Improvement of Echinacea purpurea and Ganoderma lucidum Extracts with Cell Model on Influenza A/B Infection

Since 2019, COVID-19 has been raging around the world. Respiratory viral infectious diseases such as influenza and respiratory syncytial virus (RSV) infection are also prevalent, with influenza having the ability to cause seasonal pandemics. While vaccines and antiviral drugs are available to prevent and treat disease, herbal extracts would be another option. This study investigated the inhibitory effects of extracts of Echinacea purpurea (EP) and Ganoderma lucidum (G. lucidum) and the advanced G. lucidum drink (AG) on influenza A/B viruses. To determine whether EP and G. lucidum extracts enhance cell immunity and thus prevent virus infection or act to directly suppress viruses, cell survival and hemagglutination (HA) assays were used in this study. Cells were treated with samples at different concentrations (each sample concentration was tested from the highest non-cytotoxic concentration) and incubated with influenza A/B for 24 h, with the results showing that both G. lucidum and EP extracts and mixtures exhibited the ability to enhance cell survival against viruses. In the HA assay, AG and EP extract showed good inhibitory effect on influenza A/B viruses. All of the samples demonstrated an improvement of the mitochondrial membrane potential and improved resistance to influenza A/B virus infection. EP and G. lucidum extracts at noncytotoxic concentrations increased cell viability, but only AG and EP extract directly decreased influenza virus titers. In conclusion, results indicate the ability of EP and G. lucidum extract to prevent viruses from entering cells by improving cell viability and mitochondrial dysfunction and EP extract showed direct inhibition on viruses and prevented viral infection at post-infection strategy.

An Ultra-Compact and Low-Cost LAMP-Based Virus Detection Device

Timely and accurate detection of viruses is crucial for infection diagnosis and treatment. However, it remains a challenge to develop a portable device that meets the requirement of being portable, powerless, user-friendly, reusable, and low-cost. This work reports a compact ∅30 × 48 mm portable powerless isothermal amplification detection device (material cost ∼$1 USD) relying on LAMP (Loop-Mediated Isothermal Amplification). We have proposed chromatographic-strip-based microporous permeation technology which can precisely control the water flow rate to regulate the exothermic reaction. This powerless heating combined with phase-change materials can maintain a constant temperature between 50 and 70 °C for a duration of up to 49.8 min. Compared with the conventional methods, it avoids the use of an additional insulation layer for heat preservation, greatly reducing the size and cost. We have also deployed a color card and a corresponding algorithm to facilitate color recognition, data analysis, and storage using a mobile phone. The experimental results demonstrate that our device exhibits the same limit of detection (LOD) as the ProFlex PCR for SARS-CoV-2 pseudovirus samples, with that for both being 103 copies/μL, verifying its effectiveness and reliability. This work offers a timely, low-cost, and easy way for respiratory infectious disease detection, which could provide support in curbing virus transmission and protecting the health of humans and animals, especially in remote mountainous areas without access to electricity or trained professionals.

Psychometric validation of the Chinese versions of EQ-5D-Y-3L and the experimental EQ-TIPS in children and adolescents with COVID-19.

Respiratory infectious diseases like COVID-19 profoundly impacts the health of children and adolescents, but validated instruments to measure their impacts on health-related quality of life (HRQoL) are lacking. The EQ-5D-Y-3L, widely used for youth HRQoL, now features a Chinese value set. The experimental EQ-TIPS addresses HRQoL assessment for toddlers and infants. This study tested the psychometric properties of both instruments in paediatric COVID-19 patients, and compared the performance of self-complete and proxy EQ-5D-Y-3L. This longitudinal study recruited 861 COVID-19 patients aged 0-18 years and their parental caregivers, with 311 dyads completing the follow-up. Digital administration included the EQ-TIPS, the EQ-5D-Y-3L, and Overall Health Assessment (OHA). Controls comprised 231 healthy children. Analysis encompassed known-group validity, child-parent agreement, and responsiveness to change in disease severity and OHA. COVID-19 children exhibited lower HRQoL than non-infected peers. The EQ-TIPS and the EQ-5D-Y-3L distinguished groups by disease presence, severity and symptoms, showing moderate to good known-group validity (ESs: 0.45-1.39 for EQ-TIPS, 0.44-1.91 for self-complete EQ-5D-Y-3L, and 0.32-1.67 for proxy EQ-5D-Y-3L). Child-parent agreement was moderate to good for EQ-5D-Y-3L (ICC: 0.653-0.823; Gwet's AC1: 0.470-0.738), and responsiveness was good for both EQ-TIPS Level Sum Score (LSS) (ESs: 1.21-1.39) and EQ-5D-Y-3L index scores (ESs: 1.00-1.16). This study demonstrates the reliability, validity, and responsiveness of the experimental EQ-TIPS and the EQ-5D-Y-3L in paediatric COVID-19 patients. It is the first evidence of the EQ-TIPS' responsiveness, supporting its use in assessing the impact of COVID-19 on paediatric HRQoL.

TOLL-LIKE RECEPTORS AND BRONCHIAL ASTHMA: PART 2

For the last decade, the attention of researchers has been attracted by Toll-like receptors that provide recognition of pathogens and trigger an immune response to them. As participants in acute infectious processes, with inadequate stimulation associated with mutation of genes regulating expression of the receptors, they cause the initiation or exacerbation of asthma in predisposed individuals. At the same time, the reduced function of the receptors leads to an insufficient immune response in respiratory infectious diseases, which also leads to an exacerbation of bronchial asthma. In addition, Toll-like receptors are direct elements of the pathogenesis of bronchial asthma, supporting or reducing inflammation. Thus, Toll-like receptors can not only aggravate the course of asthma, but also prevent exacerbations of the disease. Knowledge of the role of these receptors in the pathophysiology of bronchial asthma is necessary to improve diagnostic methods and timely detection of the disease. Using data on the effects realized by the receptors, medicines are being developed that are antagonists or agonists of a Toll-like receptors. The use of medicines acting on receptors in the treatment and prevention of asthma in the future may lead to increased control over the course of the disease.

Technologies and main functionalities of the telemonitoring application reCOVeryaID

The COVID-19 pandemic has highlighted the need to take advantage of specific and effective patient telemonitoring platforms, with specific reference to the constant monitoring of vital parameters of patients most at risk. Among the various applications developed in Italy, certainly there is reCOVeryaID, a web application aimed at remotely monitoring patients potentially, currently or no longer infected with COVID-19. Therefore, in this paper we present a system model, consisting of a multi-platform intelligent telemonitoring application, that enables remote monitoring and provision of integrated home care to both patients symptomatic, asymptomatic and pre-symptomatic with severe acute respiratory infectious disease or syndrome caused by viruses belonging to the Coronavirus family, as well as simply to people with respiratory problems and/or related diseases (chronic obstructive pulmonary disease or asthma). In fact, in this paper we focus on exposing the technologies and various functionalities offered by the system, which constitute the practical implementation of the theoretical framework described in detail in another paper. Specifically, the reCOVeryaID telemonitoring application is a stand-alone, knowledge base-supported application that can promptly react and inform physicians if dangerous trends in a patient's short- and long-term vital signs are detected, thus enabling them to be monitored continuously, both in the hospital and at home. The paper also reports an evaluation of user satisfaction, carried out by actual patients and medical doctors.

Evaluation of airborne transmission of respiratory contaminants in a passenger car cabin with window opening

Exhaled aerosols can be suspended in the air for long periods, facilitating the transmission of highly infectious respiratory diseases. The risk of exposure to occupants varies due to different usage conditions and driving scenarios of moving vehicles. Therefore, the present study investigates the airborne transmission of contaminants generated by coughing in a moving vehicle and explores the relationship between aerosol dispersion and fluid exchange between the interior and exterior domains of the car under the influence of window opening configurations, seating layouts and driving speeds. The results show that the cross-opening configurations provide a superior contaminant removal efficiency. The effect of seating layout on removal efficiency is significant, although it has a slight effect on air change rate (ACH). The best removal efficiency can be obtained when the passenger sits in the front seat with the right front window opening. Furthermore, the in-cabin ACH is almost linearly correlated with the driving speed. Higher speeds reduce contaminant concentrations faster. However, the risk of driver exposure does not depend solely on ACH, the peak cumulative contaminant concentration and residence time also need to be considered. This study offers data for the prevention and control of respiratory infectious diseases.

Effectiveness of Bairui granules in the treatment of respiratory tract infections: A systematic review and meta-analysis.

Respiratory tract infections (RTIs) are characterized by a high mortality rate and clinical incidence. Bairui granules (BG), which employ a method of heat elimination and detoxification, have demonstrated benefits in the treatment of infectious respiratory diseases. A computerized search of 6 databases was conducted to identify randomized controlled trials (RCTs) relevant to the treatment of RTIs with BG up to November 30, 2023. Two researchers independently conducted data extraction, risk of bias assessment, and grading analysis. To evaluate the stability of the results, trial sequential analysis was employed. This meta-analysis included 31 RCTs with a total of 4073 patients and demonstrated that the use of BG in the treatment of RTIs was associated with enhanced treatment efficacy (relative risk = 1.19, 95% credible interval: 1.16-1.22, P < .001). It also indicated a faster resolution of symptoms including pulmonary rales, cough, and fever, as well as a reduction in serological index factors, compared to the use of Western medicine treatment (WT) alone. Additionally, the duration of hospitalization for patients was significantly reduced (relative risk = -1.36, 95% credible interval: -1.55 to -1.17, P < .001). Trial sequential analysis confirmed the stability and conclusive evidence of the study results. The efficacy of treating RTIs with BG, either alone or in combination with WT, was found to be superior to WT alone. However, further high-quality RCTs are necessary to validate these outcomes. The effectiveness of treating RTIs using BG alone or in combination with WT was determined to be superior to using WT alone, with no serious adverse effects observed. However, additional RCTs are essential to further confirm the findings of this study.

Genetically Predicted Peripheral Immune Cells Mediate the Effect of Gut Microbiota on Influenza Susceptibility.

The communication mechanism of the gut-lung axis has received increasing attention in recent years, particularly in acute respiratory infectious diseases such as influenza. The peripheral immune system serves as a crucial bridge between the gut and the lungs, two organs that are not in close proximity to each other. However, the specific communication mechanism involving gut microbiota, immune cells, and their anti-influenza effects in the lung remains to be further elucidated. In this study, the effects of 731 species of peripheral immune cells and 211 different gut microbiota on influenza outcomes were analyzed using a two-sample Mendelian randomization analysis. After identifying specific species of gut microbiota and peripheral immune cells associated with influenza outcomes, mediation analyses were conducted to determine the mediating effects of specific immune cells in the protective or injurious effects of influenza mediated by gut microbiota. 19 species of gut microbiota and 75 types of peripheral immune cells were identified as being associated with influenza susceptibility. After rigorous screening, 12 combinations were analyzed for mediated effects. Notably, the down-regulation of CD64 on CD14- CD16- cells mediated 21.10% and 18.55% of the protective effect of Alcaligenaceae and Dorea against influenza, respectively. In conclusion, focusing on influenza, this study genetically inferred different types of gut microbiota and peripheral immune cells to determine their protective or risk factors. Furthermore, mediation analysis was used to determine the proportion of mediating effects of peripheral immune cells in gut microbiota-mediated susceptibility to influenza. This helps elucidate the gut-lung axis mechanism by which gut microbiota affects influenza susceptibility from the perspective of regulation of peripheral immune cells.

Two-Stream Convolutional Neural Networks for Breathing Pattern Classification: Real-Time Monitoring of Respiratory Disease Patients.

A two-stream convolutional neural network (TCNN) for breathing pattern classification has been devised for the continuous monitoring of patients with infectious respiratory diseases. The TCNN consists of a convolutional neural network (CNN)-based autoencoder and classifier. The encoder of the autoencoder generates deep compressed feature maps, which contain the most important information constituting data. These maps are concatenated with feature maps generated by the classifier to classify breathing patterns. The TCNN, single-stream CNN (SCNN), and state-of-the-art classification models were applied to classify four breathing patterns: normal, slow, rapid, and breath holding. The input data consisted of chest tissue hemodynamic responses measured using a wearable near-infrared spectroscopy device on 14 healthy adult participants. Among the classification models evaluated, random forest had the lowest classification accuracy at 88.49%, while the TCNN achieved the highest classification accuracy at 94.63%. In addition, the proposed TCNN performed 2.6% better in terms of classification accuracy than an SCNN (without an autoencoder). Moreover, the TCNN mitigates the issue of declining learning performance with increasing network depth, as observed in the SCNN model. These results prove the robustness of the TCNN in classifying breathing patterns despite using a significantly smaller number of parameters and computations compared to state-of-the-art classification models.

Short-term effects of PM2.5 components on the respiratory infectious disease: a global perspective.

Although previous research has reached agreement on the significant impact of particulate matter (PM2.5) on respiratory infectious diseases, PM2.5 acts as an aggregation of miscellaneous pollutants and the individual effect of each component has not been examined. Here, we investigate the effects of PM2.5 components, including black carbon (BC), organic carbon (OC), sulfate ion (SO4), dust, and sea salt (SS), on the morbidity and mortality of the recent respiratory disease, i.e. COVID-19. The daily data of 236 countries and provinces/states (e.g., in the United States and China) worldwide during 2020-2022 are utilized. To derive the pollutant-specific causal effects, optimal instrumental variables for each pollutant are selected from a large set of atmospheric variables. We find that one µg/m3 increase in OC increases the number of cases and death by about 3% to 6% from the mean worldwide during a lag of one day up to three days. Our findings remain consistent and robust when we change control variables such as the flight index and weather proxies, and also when applying a sine transformation to the positivity and death rate. When analyzing health effects among different areas, we find stronger impact in China, for its higher local OC concentration, as opposed to the impact in the United States. Health benefits from PM2.5 pollution reduction are comparatively high for developed regions, yet decreases in cases and deaths number are rather overt in less developing regions. Our research provides inspiration and reference for dealing with other respiratory diseases in the post-pandemic era.

Short-term effects of PM2.5 components on the respiratory infectious disease: a global perspective.

Although previous research has reached agreement on the significant impact of particulate matter (PM2.5) on respiratory infectious diseases, PM2.5 acts as an aggregation of miscellaneous pollutants and the individual effect of each component has not been examined. Here, we investigate the effects of PM2.5 components, including black carbon (BC), organic carbon (OC), sulfate ion (SO4), dust, and sea salt (SS), on the morbidity and mortality of the recent respiratory disease, i.e. COVID-19. The daily data of 236 countries and provinces/states (e.g., in the United States and China) worldwide during 2020-2022 are utilized. To derive the pollutant-specific causal effects, optimal instrumental variables for each pollutant are selected from a large set of atmospheric variables. We find that one µg/m3 increase in OC increases the number of cases and death by about 3% to 6% from the mean worldwide during a lag of one day up to three days. Our findings remain consistent and robust when we change control variables such as the flight index and weather proxies, and also when applying a sine transformation to the positivity and death rate. When analyzing health effects among different areas, we find stronger impact in China, for its higher local OC concentration, as opposed to the impact in the United States. Health benefits from PM2.5 pollution reduction are comparatively high for developed regions, yet decreases in cases and deaths number are rather overt in less developing regions. Our research provides inspiration and reference for dealing with other respiratory diseases in the post-pandemic era.

Integrating socio-psychological factors in the SEIR model optimized by a genetic algorithm for COVID-19 trend analysis

The global spread of COVID-19 has profoundly affected health and economies, highlighting the need for precise epidemic trend predictions for effective interventions. In this study, we used infectious disease models to simulate and predict the trajectory of COVID-19. An SEIR (susceptible, exposed, infected, removed) model was established using Wuhan data to reflect the pandemic. We then trained a genetic algorithm-based SEIR (GA-SEIR) model using data from a specific U.S. region and focused on individual susceptibility and infection dynamics. By integrating socio-psychological factors, we achieved a significant enhancement to the GA-SEIR model, leading to the development of an optimized version. This refined GA-SEIR model significantly improved our ability to simulate the spread and control of the epidemic and to effectively track trends. Remarkably, it successfully predicted the resurgence of COVID-19 in mainland China in April 2023, demonstrating its robustness and reliability. The refined GA-SEIR model provides crucial insights for public health authorities, enabling them to design and implement proactive strategies for outbreak containment and mitigation. Its substantial contributions to epidemic modelling and public health planning are invaluable, particularly in managing and controlling respiratory infectious diseases such as COVID-19.

Effect of oxidative stress on antigen productivity in B. Pertussis cultures

Whooping cough, also known as pertussis, is an infectious respiratory disease caused by Bordetella pertussis, a type of gram-negative, aerobic, pathogenic bacteria with a coccobacillus shape and an outer capsule. The acellular vaccine for this disease contains a combination of pertussis toxin, fimbriae, filamentous hemagglutinin, and pertactin. The main constraint in the manufacturing of the vaccine relates to pertactin productivity due to its low abundance in the fermentation broth. Being the most abundant nutrient in the media, variability in initial glutamate concentration is hypothesized to be a major cause of process variability. This study proposes the combined use of cytometry and chromatography based separation to study the impact of glutamate-induced oxidative stress on the growth and productivity of pertactin antigen. Surface expression of pertactin was observed using fluorescence microscopy and flow cytometry while extracellular concentration was quantified using affinity chromatography. Oxidative stress levels and secretion of NADPH, a crucial reactant in antioxidant reactions, were monitored in flask and bioreactor experiments. The results established clear correlations between oxidative stress with growth and productivity and differentiate between the reduction in productivity to growth and to synthesis rate of pertactin. These findings are industrially relevant for improving productivity and reducing process variability.

Long-term exposure to road traffic noise and acute lower respiratory infections in the Danish Nurse Cohort

BackgroundLong-term exposure to road traffic noise is associated with cardiovascular disease, but the evidence on respiratory diseases is just emerging. We aimed to examine the association between long-term exposure to road traffic noise and the incidence of acute lower respiratory infections (ALRIs) in adults. MethodsWe followed 23,141 female nurses (age ≥ 44 years) from the Danish Nurse Cohort from baseline (1993 or 1999) to their first hospital contact (inpatient, outpatient, or emergency room) for ALRI, death, emigration or the end of 2015. The residential annual mean levels of road traffic noise (Lden) during the follow-up were estimated using the Nord2000 model. We applied time-varying Cox models to estimate the association of 3-year mean exposure to Lden with ALRIs incidence and piecewise analysis to estimate the threshold of Lden. We examined the robustness of the results by adjusting for residential exposure to air pollution, and the effect modification by attained age, socioeconomic status (SES), comorbidity, and lifestyle. ResultsDuring 18.5 years of follow-up, 2,004 nurses developed ALRIs. In a linear model, we detected a statistically significant positive association between Lden and ALRI, with a hazard ratio (HR) of 1.11 (95 % confidence interval (CI): 1.04, 1.17) per 9.2 dB (interquartile range, IQR). We observed non-linear association with a threshold at 57 dB, above which the HR was 1.25 (95 % CI: 1.09, 1.43) per IQR. Further adjustment for PM2.5 reduced the HRs slightly to 1.21 (95 % CI: 1.04, 1.40). The associations were stronger for nurses with asthma, and in those with lowest SES. ConclusionWe present novel findings in support of the association between long-term exposure to road traffic noise and ALRIs, independent of air pollution, suggesting noise as a risk factor for infectious respiratory diseases.

Chinese Medicine for Treatment of COVID-19: A Review of Potential Pharmacological Components and Mechanisms.

Coronavirus disease 2019 (COVID-19) is an acute infectious respiratory disease that has been prevalent since December 2019. Chinese medicine (CM) has demonstrated its unique advantages in the fight against COVID-19 in the areas of disease prevention, improvement of clinical symptoms, and control of disease progression. This review summarized the relevant material components of CM in the treatment of COVID-19 by searching the relevant literature and reports on CM in the treatment of COVID-19 and combining with the physiological and pathological characteristics of the novel coronavirus. On the basis of sorting out experimental methods in vivo and in vitro, the mechanism of herb action was further clarified in terms of inhibiting virus invasion and replication and improving related complications. The aim of the article is to explore the strengths and characteristics of CM in the treatment of COVID-19, and to provide a basis for the research and scientific, standardized treatment of COVID-19 with CM.

Otitis Media with Effusion in Patients with COVID-19: A Single-Center Study in China

BackgroundThe swift global spread of coronavirus disease 2019 (COVID-19), a respiratory ailment primarily marked by pulmonary symptoms, has been linked to the involvement of various organs, including the intestines, kidneys, throat, and ears. Otitis media with effusion (OME), often succeeding an upper respiratory tract infection, mirrors its incidence. As a respiratory infectious disease, it prompts the query of whether the COVID-19 pandemic has spurred an uptick in OME and whether the COVID-19 virus persists in middle ear effusion (MEE) for an extended period. MethodsTo gauge the incidence of OME in the population during the COVID-19 pandemic, a tailored questionnaire was disseminated and subsequently analyzed. Assessing the rise in OME incidence during the pandemic, we compared the proportion of OME cases in the otology outpatient department between pandemic and non-pandemic periods. Statistical analysis involved a t-test. Simultaneously, MEE was collected from patients with COVID-19-associated OME during the pandemic to ascertain the presence of SARS-CoV-2 in MEE via polymerase chain reaction. ResultsBased on the questionnaire data, the estimated OME incidence in the population is approximately 31.4%. In contrast to the non-pandemic period, the percentage variation in the OME outpatient proportion was 71.4% (P < 0.05). Among the 61 MEE samples, 13 polymerase chain reaction results were positive, constituting 21.31%. Nasopharyngeal swabs yielded negative results. Notably, only one patient experienced OME recurrence after 1 month of auripuncture. ConclusionsCOVID-19 can trigger an escalation in OME cases. Even when nasopharyngeal swabs show negative results, SARS-CoV-2 can endure in MEE for an extended duration, suggesting the potential for asymptomatic COVID-19 transmission and recurrence within the population.

Exploring the use of exhaled breath as a diagnostic tool for pulmonary TB.

Despite its historical decline, TB remains a significant cause of infectious disease-related global deaths. The lack of reliable diagnostic tests for vulnerable groups, such as children and immunocompromised patients, remains a challenge for TB control. For decades, it has been recognised that exhaled breath has great potential as a non-invasive and universally accessible clinical alternative to sputum and invasive sampling methods. Although translation into clinical practice has not yet occurred, there has been significant progress with promising results in various applications, including diagnosis, estimation of infectiousness, and monitoring of treatment response. More recently, the COVID-19 pandemic reignited global interest in this field and technological advances have further accelerated its development. In the coming decade, breath sampling will enhance our understanding of respiratory infectious diseases and host-immune responses, which may lead to clinical applications. Here we discuss the diagnostic landscape of TB and the current state of the art of breath sampling.

Assessment of airborne viral transmission risks in a large-scale building using onsite measurements and CFD method

Screening patients for potential respiratory infections through nucleic acid sampling was a critical non-pharmacologic intervention during a respiratory infectious disease pandemic. Evaluating the cross-infection risk of crowded activities conducted indoors is necessary. We conducted a field study of this event in a large-scale stadium and measured the variation in CO2 concentrations. We conducted simulations on the stadium's flow field, CO2 and N2O concentration distribution using the CFD method, which was validated by the on-site measured data. We simulated the diffusion of virus aerosols exhaled by the sampled individuals under an all-fresh and primary return air system, respectively. It was found that space morphology and airflow pattern are the main factors influencing the concentration distribution of human exhaled contaminants. Primary return air systems can reduce the infection risk for sampled individuals by the filtration system and improve the airflow pattern. With the ratio of fresh air to return air of 1.2, the primary return air systems with 70 %, 85 %, and 95 % filtration levels can reduce the infection risk by an average of 54.5 %, 58.3 %, and 62.1 %, respectively, compared to all-fresh air system. It is necessary to optimize the processes and queue setups for nucleic acid sampling activities in the room based on the room airflow characteristics and the return air system using an efficient filtration system.

The relationship between occupant behaviour and indoor air quality in Malaysian hospital outpatient departments: A multistage cross-sectional study

IntroductionPoor indoor air quality (IAQ) in healthcare settings may adversely impact occupants’ well-being and promote transmission of infectious respiratory disease. However, evidence on its potentially modifiable determinants, including occupant behaviour, remains scarce. This study aims to determine the relationship between occupant behaviour and IAQ in Malaysian hospital outpatient departments (OPDs). MethodsA multistage cross-sectional study of six randomly selected Malaysian public hospital OPDs was conducted. In stage one, IAQ parameters, including temperature, relative humidity (RH), air velocity (AV), carbon dioxide (CO2), total bacterial count (TBC), and total fungal count (TFC) were measured. In stage two, an observation form based on the Korsavi and Montazami tool for measuring adaptive behaviour was used to examine occupant density, activities, and operation of building envelopes and appliances. Simple correlation, partial correlation, and linear regression analyses were performed to examine the relationship between occupant behaviour and IAQ parameters. ResultsThe IAQ of selected hospital OPDs complied with established standards, except for temperature and AV. Occupant density was positively correlated with temperature and CO2. Meanwhile, occupants' activities including slow walking and brisk walking were positively correlated with temperature, AV, CO2, TBC and TFC. Conversely, occupants' opening of windows and doors were positively correlated with temperature and AV but negatively correlated with CO2, TBC and TFC. Finally, turning on fans was positively correlated with AV but negatively correlated with TBC, whereas turning on air conditioner was positively correlated with CO2. Among occupants’ behaviour, opening of windows and doors contributed the most to variation in IAQ parameters. ConclusionsThe study findings suggest that IAQ in hospital OPDs are influenced by occupant density, activities, and operation of doors, windows, and appliances. Prospective hospital IAQ guidelines should incorporate policies and measures targeting these factors to ensure occupants’ best practices in maintaining healthy hospital indoor air environments.