Susceptible Persons Research Articles

Estimating the population-level effects of nonpharmaceutical interventions when transmission rates of COVID-19 vary by orders of magnitude from one contact to another

Statistical physicists have long studied systems where the variable of interest spans many orders of magnitude, the classic example is the relaxation times of glassy materials, which are often found to follow power laws. A power-law dependence has been found for the probability of transmission of COVID-19, as a function of length of time a susceptible person is in contact with an infected person. This is in data from the United Kingdom's COVID-19 app. The amount of virus in infected people spans many orders of magnitude. Inspired by this, I assume that the power-law behavior found in COVID-19 transmission is due to the effective transmission rate varying over orders of magnitude from one contact to another. I then use a model from statistical physics to estimate that if a population all wear FFP2/N95 masks, this reduces the effective reproduction number for COVID-19 transmission by a factor of approximately nine. Published by the American Physical Society 2024

Strength and durability of indirect protection against SARS-CoV-2 infection through vaccine and infection-acquired immunity.

Early investigation revealed that COVID-19 vaccines confer indirect protection to fully susceptible and unvaccinated persons, defined as a reduced risk of SARS-CoV-2 infection among social contacts of vaccinated individuals. However, indirect protection from infection-acquired immunity and its comparative strength and durability to vaccine-derived indirect protection in the current epidemiologic context of high levels of vaccination, prior infection, and novel variants are not well characterized. Here, we show that both infection-acquired and vaccine-derived immunity independently yield indirect protection to close social contacts with key differences in their strength and waning. Analyzing anonymized data from a system-wide SARS-CoV-2 surveillance program of 177,319 residents across 35 California state prisons from December 2021 to December 2022 in a case-control design, we find that vaccine-derived indirect protection against Omicron SARS-CoV-2 infection is strongest within three months post-vaccination [30% (95% confidence interval: 20-38%)] with subsequent modest protection, whereas infection-acquired immunity provides 38% (24-50%) indirect protection to roommates for 6 months after SARS-CoV-2 infection, with moderate indirect protection persisting for over one year. Variant-targeted vaccines (bivalent formulation including Omicron subvariants BA.4/BA.5) confer strong indirect protection for at least three months [40% (3-63%)]. These results have important implications for understanding the long-term transmission dynamics of SARS-CoV-2 and can guide vaccine policy and public health measures, especially in high-risk environments such as prisons.

Can the infection risk in elevators be negligible? A comparative study of airborne infection probability in elevators and conference rooms

People in crowded and poorly ventilated elevators are at risk of respiratory infection. However, due to the short duration of the elevator ride, the transmission of respiratory diseases in elevators does not get enough attention. To evaluate the infection risk, this study investigated the airborne transmission of respiratory diseases in the hospital elevator by comparison to the conference room. A validated computational fluid dynamics (CFD) model was adopted to simulate airflow, temperature and tracer gas dispersion in the elevator and conference room. We used Wells-Riley model to evaluate the infection probability of the susceptible persons. In addition, the influences of source patient posture and ventilation strategy on the transmission of tracer gas were analyzed. The results showed that the infection probability in the elevator with 5 min (average 2.70%) was higher than that in the conference room with 50 min (average 1.77%). The effects of source patient posture and ventilation strategy on the infection probability in the elevator were more significant than those in the conference room. Local air circulation could gather the tracer gas inside a confined space in the elevator and led to a high infection probability. The infection risk of respiratory diseases in the elevator was non-negligible.

Prolonged eosinophilia caused by Strongyloidiasis in a patient with rheumatoid arthritis treated with Upadacitinib.

Rheumatoid arthritis (RA) is a systemic disease, which is caused by dysregulation of the immune system in the susceptible persons, making them immunocompromised and prone to infections during the course of their disease. The majority of RA patients are being treated with immunosuppressive drugs which render them even more immunocompromised. We present a Caucasian patient living in South-eastern Europe who developed prolonged eosinophilia during the treatment of RA with upadacitinib. After a comprehensive work-up she was diagnosed with Strongyloidiasis although living in non-endemic region of the world. We emphasize the importance of regular follow-up of immunocompromised patients and raise awareness of not only typical but also atypical infections which can occur during the course of the disease.

Analysis and optimal control for SEIR mathematical modeling of COVID-19

In this paper a mathematical model of SEIR type is formulated. represented by modeling the coronavirus epidemic. In this present study, we consider a mathematical model that incorporates the whole population and variability in transmission between reported and unreported populations. The global stability of the disease free equilibrium (DFE) point is established. The basic reproduction number R0 is calculated. We introduce into our model two controls which are vaccination ofsusceptible humans denoted by u and treatment of infected humans designed by v. In addition, this model takes into consideration the control of contact between infectious individuals and susceptible persons A numerical simulation of the model is made.

An Investigation of a Community Chickenpox Outbreak with a Fatal Case, Songkhla Province, Thailand, October 2022

In October 2022, a suspected chickenpox death was notified. A field investigation was done to verify the diagnosis and cause of death, describe the epidemiological characteristics, identify risk factors, and control the outbreak. We conducted a descriptive study and a matched case-control study. A case was defined as a person with multiple stages of skin lesions on at least two body areas in Subdistrict from 1 Aug 2022 to 24 Oct 2022. We reviewed medical records and searched for cases house-to-house. For the matched case-control study, cases were chickenpox cases residing in Bo Tru Subdistrict, from 1 Aug 2022 to 14 Oct 2022. Controls were neighbors without symptoms or chickenpox history, matched by age. Samples were tested using the reverse transcription polymerase chain reaction technique. Environmental surveys were performed. We identified 30 cases including the deceased, who was 49 years old. The median (interquartile range) age of the cases was 11 (7–38) years. Seventeen were elementary-school students. None of the cases received chickenpox vaccination or had a history of chickenpox. The secondary attack rate among household contacts was 41.2% (14/34). Reverse transcriptase polymerase chain reaction tests from three cases were all positive. Being a close contact with a case and sharing personal utensils were risk factors. We strengthened the surveillance system for early detection and treatment and provided risk communication in the community. Chickenpox cases should be isolated from susceptible persons. Standard treatment guidelines for complicated cases should be distributed among healthcare services.

The potential of local exhaust combined with mixing and displacement ventilation systems to mitigate COVID-19 transmission risks

The performance of two types of air diffusers, a perforated duct and a low-velocity unit coupled with local exhausts, on airborne transmission and cross-infection was investigated in a meeting room. The effect of air diffusers’ locations on airborne transmission was investigated. Six local exhausts were installed above six workstations at 2.0 m height. Respiratory-generated airborne pathogens were simulated using SF6 in the exhaled air of the manikin acting as an infected person. The SF6 concentration in the inhaled air of five susceptible persons remained steady with perforated duct located on the ceiling and at 1.7 m height attached to the corridor wall, but fluctuated greatly when perforated duct were located on the floor, although with a much lower concentration level. The perforated duct under the warm window showed the best potential for mitigating airborne transmission. The concentration in the inhaled air was varied with horizontally supplied low-velocity unit, but much steadier with low-velocity unit at 1.7 m attached to the wall. With an adjusted airflow pattern from low-velocity unit, the inhaled concentration was much lower and uniform among the five susceptible persons. The contaminant removal effectiveness (CRE) was 4.3 with perforated duct under a warm window on the floor. With an adjusted airflow pattern from low-velocity unit, the CRE was much more consistent and increased from 2.1 to 3.9 with an airflow rate from 61 l/s to 116 l/s. The infection probability was the lowest with the perforated duct on the floor and adjusted low-velocity unit.

Air quality monitoring device to mitigate the spread of COVID-19 in educational buildings

The COVID-19 pandemic brought significant consequences on healthcare systems, economy, and politics. Nowadays, we know that the pathogen responsible for COVID-19 is transmitted mainly by aerosol droplets exhaled by infected individuals, which remain suspended in indoor air. There has been widespread interest in monitoring the CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$CO_2$$\\end{document} levels in indoor spaces since an infected patient exhales CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$CO_2$$\\end{document} and infectious aerosols when breathing. So, we designed and built an Air Quality Monitoring Device (AQMD) that measures and analyzes the levels of CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$CO_2$$\\end{document} and particulate matter in the classrooms of a university with the aim of mitigating the spread of COVID-19. We divided the AQMD design into 2 phases: (i) data measurement and (ii) estimation of infection risk. Specifically, we measured the air quality in 3 classrooms of a university during different types of activities. Using these data, we calculated the recommended CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$CO_2$$\\end{document} threshold for our classroom setting and estimated the probability of COVID-19 infection of a susceptible person. Our research shows that indoor CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$CO_2$$\\end{document} concentrations and the probability of COVID-19 infection are influenced mainly by the type of activity and the number of windows open; besides, the number of students does not significantly impact the indoor CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$CO_2$$\\end{document} concentrations levels because the range of students in the test scenario (18 to 31) was relatively small.

Cases of Meningococcal Disease Associated with Travel to Saudi Arabia for Umrah Pilgrimage - United States, United Kingdom, and France, 2024.

Invasive meningococcal disease (IMD), caused by infection with the bacterium Neisseria meningitidis, usually manifests as meningitis or septicemia and can be severe and life-threatening (1). Six serogroups (A, B, C, W, X, and Y) account for most cases (2). N. meningitidis is transmitted person-to-person via respiratory droplets and oropharyngeal secretions. Asymptomatic persons can carry N. meningitidis and transmit the bacteria to others, potentially causing illness among susceptible persons. Outbreaks can occur in conjunction with large gatherings (3,4). Vaccines are available to prevent meningococcal disease. Antibiotic prophylaxis for close contacts of infected persons is critical to preventing secondary cases (2).

Vaccine value profile for herpes simplex virus

Herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) are chronic, highly prevalent viral infections that cause significant morbidity around the world. HSV-2 is sexually transmitted and is the leading cause of genital ulcer disease (GUD). It also increases the risk of HIV acquisition, fueling the HIV epidemic. HSV-1 is typically acquired in childhood through nonsexual contact and contributes to oral and ocular disease, but it can also be sexually transmitted to cause GUD. Both HSV-1 and HSV-2 cause neonatal herpes and neurologic disease. Given the ubiquitous nature of HSV-1 and HSV-2 infections and the limited existing prevention and control measures, vaccination would be the most efficient strategy to reduce the global burden of morbidity related to HSV infection. Vaccine strategies include prophylactic vaccination, which would prevent infection among susceptible persons and would likely be given to adolescents, and therapeutic vaccinations, which would be given to people with symptomatic genital HSV-2 infection. This document discusses the vaccine value profile of both types of vaccines.This ‘Vaccine Value Profile’ (VVP) for HSV is intended to provide a high-level, holistic assessment of the information and data that are currently available to inform the potential public health, economic and societal value of pipeline vaccines and vaccine-like products. This VVP was developed by subject matter experts from academia, non-profit organizations, government agencies and multi-lateral organizations. All contributors have extensive expertise on various elements of the HSV VVP and collectively aimed to identify current research and knowledge gaps. The VVP was developed using only existing and publicly available information.

Prospects for Controlling Hepatitis B Globally.

Infection with the hepatitis B virus (HBV) is highly prevalent globally. Over 250 million people suffer from chronic hepatitis B, and more than 800,000 patients die each year due to hepatitis B complications, including liver cancer. Although protective HBV vaccines are recommended for all newborns, global coverage is suboptimal. In adults, sexual transmission is by far the most frequent route of contagion. The WHO estimates that 1.5 million new HBV infections occur annually. Oral nucleos(t)ide analogues entecavir and tenofovir are the most frequent antivirals prescribed as HBV therapy. Almost all patients adherent to the medication achieve undetectable plasma viremia beyond 6 months of monotherapy. However, less than 5% achieve anti-HBs seroconversion, and viral rebound occurs following drug discontinuation. Therefore, nucleos(t)ide analogues need to be lifelong. New long-acting formulations of tenofovir and entecavir are being developed that will maximize treatment benefit and overcome adherence barriers. Furthermore, new antiviral agents are in development, including entry inhibitors, capside assembly modulators, and RNA interference molecules. The use of combination therapy pursues a functional HBV cure, meaning it is negative for both circulating HBV-DNA and HBsAg. Even when this goal is achieved, the cccDNA reservoir within infected hepatocytes remains a signal of past infection, and HBV can reactivate under immune suppression. Therefore, new gene therapies, including gene editing, are eagerly being pursued to silence or definitively disrupt HBV genomes within infected hepatocytes and, in this way, ultimately cure hepatitis B. At this time, three actions can be taken to push HBV eradication globally: (1) expand universal newborn HBV vaccination; (2) perform once-in-life testing of all adults to identify susceptible HBV persons that could be vaccinated (or re-vaccinated) and unveil asymptomatic carriers that could benefit from treatment; and (3) provide earlier antiviral therapy to chronic HBV carriers, as being aviremic reduces the risk of both clinical progression and transmission.

Effectiveness of portable air cleaners in mitigating respiratory virus transmission risk

Portable air cleaners (PACs) have shown promising potential in reducing the risk of SARS-CoV-2 infection by effectively removing pollutant particles and optimizing airflow patterns. This study focused on a simulated scenario where an infected source and a susceptible person engage in conversation within a naturally ventilated room. By combining the Eulerian fluid method with the Lagrangian particle tracking model, a comprehensive insight into indoor airflow patterns and the dispersion of virus-laden droplets was gained. As deposited droplets may be resuspended or in contact thereby increasing the potential risk of infection, the deposition of droplets of different sizes in different susceptible areas was also specifically analyzed. The impacts of three variables, namely the configuration of the PAC’s opening, air flow rate, and positioning, on the transmission of virus-laden droplets were investigated. The results highlighted the significant role of PAC utilization in effectively capturing droplets emitted by the infected source and reducing virus concentration in the vicinity of the susceptible person, thereby mitigating the risk of transmission. Notably, the design and orientation of the suction opening emerged as crucial factors. Among the various cases studied, the optimal control and prevention performance against the virus was achieved with a virus concentration reduction rate of 97.4% when the PAC had an opening configuration with a larger single-sided suction opening facing the infected source, an airflow rate of 200 m3 h−1, and was positioned at the center of the tabletop between the infected source and the susceptible person. This research underscored the importance of employing PACs with appropriate settings to enhance indoor air quality and minimize the potential for SARS-CoV-2 transmission in similar scenarios.

An intelligent prediction model of epidemic characters based on multi‐feature

AbstractThe epidemic characters of Omicron (e.g. large‐scale transmission) are significantly different from the initial variants of COVID‐19. The data generated by large‐scale transmission is important to predict the trend of epidemic characters. However, the results of current prediction models are inaccurate since they are not closely combined with the actual situation of Omicron transmission. In consequence, these inaccurate results have negative impacts on the process of the manufacturing and the service industry, for example, the production of masks and the recovery of the tourism industry. The authors have studied the epidemic characters in two ways, that is, investigation and prediction. First, a large amount of data is collected by utilising the Baidu index and conduct questionnaire survey concerning epidemic characters. Second, the β‐SEIDR model is established, where the population is classified as Susceptible, Exposed, Infected, Dead and β‐Recovered persons, to intelligently predict the epidemic characters of COVID‐19. Note that β‐Recovered persons denote that the Recovered persons may become Susceptible persons with probability β. The simulation results show that the model can accurately predict the epidemic characters.

Feasibility test of a breath-tracking personalized ventilation (BTPV) system for mitigating the airborne transmission of respiratory virus

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) spreads from one person to another primarily via airborne transmission. Personalized ventilation (PV) has been recommended as one of the effective tools for protecting people from infection. Compared to personal protective equipment, such as masks, PV has the potential to provide a more comfortable experience. A first-of-its-kind breath-tracking personalized ventilation (BTPV) system was invented and tested for feasibility in a simulated indoor environment with two breathing manikins. It basically delivers fresh or clean air to people's breathing zones as well as removes and cleans the exhaled air locally in sync with the breathing cycle. The results demonstrate that a BTPV system could: 1) reduce more exposure to infectious particles (up to 88%) for a susceptible person than most of the commonly used interventions, including surgical masks; 2) reduce more than 70% exposure when the susceptible and infector manikins were within 2 m from each other; 3) work more effectively on the infector (50%) than on the susceptible person (40%) if only one of them was wearing it. The BTPV system thus gives evidence of its superior performance and greater potential over masks and other interventions to protect people in scenarios of all kinds, including circumstances where personal connections are important, high-volume breathing or food intake is necessary, or social distancing is not possible to be maintained.

Opioid dependency and intervention: A critical examination of the neurobiological foundations

Opioids strongly modulate numerous physiological and psychological functions. They may induce euphoria and analgesia, which cultures have sought for generations when administered abruptly. Chronic opioid usage alters neural circuitry and creates a drug-dependent condition. During drug withdrawal, allostatic alterations caused by drug dependence are evident. Drug use stops a temporary coordinated allostatic re-established of neural circuits, which manifest as physiology and psychological consequences that are the opposite of those seen throughout sensitive drug intoxicates. Physical withdrawal symptoms, for example, go away in a matter of days, although other symptoms, such as dysphoria, sleeplessness, and anxiety, might last. Some adaptations, like gathered connections, can become permanent. The brain circuitry, cellular processes, and opioids drug dependence suggest a potential role for neuroinflammation. The taught association involving opioids and alleviation from a preexisting or withdrawal-induced anxiogenic and dysphoric state leads to opioids-addicted behaviors. Drug cravings among susceptible persons living in an increasingly pressured environment would be fueled by a taught link between drug use and respite from unpleasant moods. We contend that the present opioids crisis in the USA is exacerbated by this path to addiction.

Diagnosis of Celiac Disease in a Patient with Isolated Refractory Dyspepsia and GERD: A Case Report

Celiac disease is a chronic autoimmune illness that develops in genetically susceptible persons who consume gluten that causes damage to the small intestine. The average global prevalence of CD is between 0.5 and 1%, despite regional variations in the disease's frequency. In this report, we present a 34-year-old patient with a complaint of epigastric pain and burning with a history of nausea and vomiting. She complained of severe gastric pain, bloating, discomfort, burning, and digestive problems. Endoscopy and colonoscopy were performed due to her lower abdominal pain and it showed that the asymptomatic with isolated dyspepsia patient was diagnosed with celiac disease. Every six months, anti-TCG, IgG, and IgA levels were monitored and they improved at the same time that the patient's symptoms did. Endoscopy must be performed in young patients, who have no signs of celiac disease and have a positive laboratory test.

Prevention and control of pediatric tinea capitis

Tinea capitis is a superficial fungal infection of the scalp and hair caused by Dermatophytes. It represents the most prevalent superficial fungal infection among preadolescent children worldwide, including in developing countries such as China. The highly contagious nature of tinea capitis can result in outbreaks within communal settings for children. Furthermore, pustular lesions associated with this condition can lead to permanent scarring and hair loss, imposing a significant psychological burden on affected children and their parents. This article aims to provide a comprehensive literature review encompassing the susceptible person, epidemiological characteristics, trends, etiology, modes of transmission, clinical manifestations, treatment, and prevention strategies of tinea capitis. The ultimate objective is to raise awareness, implement effective prevention and control measures, interrupt the transmission cycle, and ultimately reduce the incidence of tinea capitis in the pediatric population.

Infectivity of exhaled SARS-CoV-2 aerosols is sufficient to transmit covid-19 within minutes

Exhaled SARS-CoV-2-containing aerosols contributed significantly to the rapid and vast spread of covid-19. However, quantitative experimental data on the infectivity of such aerosols is missing. Here, we quantified emission rates of infectious viruses in exhaled aerosol from individuals within their first days after symptom onset from covid-19. Six aerosol samples from three individuals were culturable, of which five were successfully quantified using TCID50. The source strength of the three individuals was highest during singing, when they exhaled 4, 36, or 127 TCID50/s, respectively. Calculations with an indoor air transmission model showed that if an infected individual with this emission rate entered a room, a susceptible person would inhale an infectious dose within 6 to 37 min in a room with normal ventilation. Thus, our data show that exhaled aerosols from a single person can transmit covid-19 to others within minutes at normal indoor conditions.

Mental Health Impacts Of COVID-19 Pandemic: A Critical Review

During the coronavirus (COVID-19) epidemic, a variety of psychological issues and serious effects for mental health, such as uncertainty, frustration, stress, sadness, suicidal thoughts, and worry arose gradually up to 25%. This study aims to find the impacts of COVID-19 on mental health of people. From literature studies it was analyzed that how coronavirus affects the psychological health especially of health care workers and infected patients. The significance of risk and protective variables in the development of mental diseases in susceptible persons has also been studied. COVID-19 had affected not only the mental health of COVID-19 patients, but also their relatives, healthcare personnel, children, and the general public. Protocols for assistance, similar to those used in disasters, should encompass key areas for both the individual and communal mental health of the population. Improving sleep, relaxation, and mood might aid clinical decision making during important moments, such as when there is an influx of sick persons and COVID-19 therapies are being implemented. The psychosocial advice given by the WHO, CDC, and the NHS, among others, should be addressed to solve these mental health issues and return to normalcy.

Risk assessment of respiratory droplet infections caused by coughing in various indoor dynamic environments

Since most respiratory infections occur in confined spaces, it is necessary to further investigate the effect of wake caused by human movement on droplet dispersion. This paper investigates the effects of droplet dispersion in dynamic indoor environment by using computational fluid dynamics when the infected person remained stationary, and the susceptible person moved at different speeds and at different distances from the infected person. The modified Wells-Riley model, which introduced the concept of local quantum concentration, was used to estimate the transient infection probability of a virtual person inhaling droplets at 1 m distance from an infected person. The results show that the human motion speed has a stronger effect on the diffusion of 1 μm droplets. The distance between people had a more significant effect on the resuspension and diffusion of 34 μm droplets. The effect of both is very small for droplets above 67 μm. The higher human movement speed results in much higher probability of infection within 40 s–55 s, and has the highest probability about 96.2 × 10−6. The distance between people mainly affects the probability of infection at the beginning of the cough (10s). When the distance is 0.1 m, the infection probability is highest at 10 s with a value of 232.1 × 10−6. In addition, it was found that when one person passes another, a distance of at least 1 m is maintained between them. In this paper, this study provides greater insight into the impact of human activities on infection risk in indoor environments.