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This work proposes a non-smooth epidemic model with a two-threshold control strategy. Under the two-threshold policy, social distancing is suggested when the infection level exceeds a certain threshold, and contact tracing is implemented and isolation rate is improved when the infection level exceeds a higher threshold. The global dynamics of the non-smooth system is investigated and it reveals that the disease-free equilibrium, or one of the three endemic equilibria of the subsystems, or one of the two pseudo-equilibria may be globally asymptotically stable, which depends on the two threshold levels and the intensity of control measures. The global stability of the pseudo-equilibrium indicates that the disease could be maintained at a previously given level by choosing the two thresholds properly. It is also obtained that at low thresholds and high intensity of control measures, the peak value is low and peak time is late for the unisolated infections and daily new infections, and the number of cumulative infections is small. However, the effects of control measures are very limited both on the final trend of the epidemic and the cumulative infections if threshold levels are too high. • A non-smooth epidemic model with a two-threshold control strategy is proposed. • Disease-free equilibrium, or endemic equilibrium, or pseudo-equilibrium may be globally asymptotically stable. • The disease could be maintained at a previously given level for proper thresholds. • Low thresholds and high implementation intensity of control measures are beneficial for disease control. • Effects of control measures are very limited if thresholds levels are too high. [ABSTRACT FROM AUTHOR]

We develop a mathematical model to investigate the effect of contact tracing on containing epidemic outbreaks and slowing down the spread of transmissible diseases. We propose a discrete-time epidemic model structured by disease-age which includes general features of contact tracing. The model is fitted to data reported for the early spread of COVID-19 in South Korea, Brazil, and Venezuela. The calibrated values for the contact tracing parameters reflect the order pattern observed in its performance intensity within the three countries. Using the fitted values, we estimate the effective reproduction number Re and investigate its responses to varied control scenarios of contact tracing. Alongside the positivity of solutions, and a stability analysis of the disease-free equilibrium are provided. [ABSTRACT FROM AUTHOR]

We evaluate approaches to vaccine distribution using an agent-based model of human activity and COVID-19 transmission calibrated to detailed trends in cases, hospitalizations, deaths, seroprevalence, and vaccine breakthrough infections in Florida, USA. We compare the incremental effectiveness for four different distribution strategies at four different levels of vaccine supply, starting in late 2020 through early 2022. Our analysis indicates that the best strategy to reduce severe outcomes would be to actively target high disease-risk individuals. This was true in every scenario, although the advantage was greatest for the intermediate vaccine availability assumptions and relatively modest compared to a simple mass vaccination approach under high vaccine availability. Ring vaccination, while generally the most effective strategy for reducing infections, ultimately proved least effective at preventing deaths. We also consider using age group as a practical surrogate measure for actual disease-risk targeting; this approach also outperforms both simple mass distribution and ring vaccination. We find that quantitative effectiveness of a strategy depends on whether effectiveness is assessed after the alpha, delta, or omicron wave. However, these differences in absolute benefit for the strategies do not change the ranking of their performance at preventing severe outcomes across vaccine availability assumptions. Author Summary: We use our agent-based model of SARS-CoV-2 transmission to evaluate alternative vaccine distribution strategies over a range of vaccine supply scenarios. We find that strategies targeting transmission (e.g., ring vaccination) perform best in preventing infections, but targeting disease risk prevents more instances of severe outcomes. Specifically, strategies based on age, or age and comorbidities—which do not require contact tracing—resulted in the fewest hospitalizations in our model. These strategy rankings held true across all vaccine supply scenarios and were robust to the introduction of SARS-CoV-2 variants. While the quantitative results cannot be directly applied to other settings (as we used a synthetic population calibrated to the State of Florida), the rankings of strategies should be more generalizable. [ABSTRACT FROM AUTHOR]

Background: The COVID-19 pandemic is the most significant worldwide health catastrophe, with massive impacts observed particularly among the healthcare workers. Stress among healthcare workers is a significant and pervasive issue that can have profound implications for both the well-being of healthcare professionals and the quality of patient care. This study aimed to determine the prevalence of stress related to the COVID-19 pandemic and the associated factors among the healthcare workers (HCWs). Methods: A retrospective cross-sectional study was conducted involving 533 HCWs in Kota Setar District Health Office. Related data was collected between January and June 2021. Stress was measured using the Depression Anxiety Depression Scale 21 (DASS-21). Other variables included in this study were sociodemographic and employment factors. The associated factors and predictors were determined by employing chi-square test and multivariate logistic models. Results: COVID-19 related stress was reported at 10.5%. HCWs who work at the district health offices and those with degree or higher qualifications had 2.3 (AOR = 2.310, 95% CI: 1.177–4.535) and 3 (AOR = 2.899, 95% CI: 1.613–5.211) higher odds of experiencing stress compared to those working in the clinics and had lower qualifications (diploma or less). Conclusions: The mental wellbeing of the HCWs participated in this study had been affected negatively by the COVID-19 pandemic, resulting in one in 10th of the HCWs were experiencing stress during the COVID-19 pandemic, with higher risk observed among those working at the district health office and HCWs with higher qualifications or ranking. This is expected since COVID-19 was a new and unprecedented outbreak associated with massive number of mortalities that requires active contact tracing and surveillance which commonly conducted at district health office level. Active intervention needed to cope with the overwhelming stress and working condition to ensure effective rehabilitation are in place and quality of work were not jeopardized. [ABSTRACT FROM AUTHOR]

South Korea's remarkable success in controlling the spread of COVID-19 during the pre-Omicron period was based on extensive contact tracing and large-scale testing. Here we suggest a general criterion for tracing and testing based on South Korea's experience, and propose a new framework to assess tracing and testing. We reviewed papers on South Korea's response to COVID-19 to capture its concept of tracing and testing. South Korea expanded its testing capabilities to enable group tracing combined with preemptive testing, and to conduct open testing. According to our proposed model, COVID-19 cases are classified into 4 types: confirmed in quarantine, source known, source unknown, and unidentified. The proportion of the first two case types among confirmed cases is defined as "traced proportion", and used as the indicator of tracing and testing effectiveness. In conclusion, South Korea successfully suppressed COVID-19 transmission by maintaining a high traced proportion (> 60%) using group tracing in conjunction with preemptive testing as a complementary strategy to traditional contact tracing. [ABSTRACT FROM AUTHOR]

Background: HIV partner notification services can help people living with HIV (PLHIV) to identify, locate, and inform their sexual and injecting partners who are exposed to HIV and refer them for proper and timely counseling and testing. To what extent these services were used by PLHIV and what are the related barriers and facilitators in southeast Iran are not known. So, this study aimed to explore HIV notification and its barriers and facilitators among PLHIV in Iran. Methods: In this qualitative study, the number of 23 participants were recruited from November 2022 to February 2023 including PLHIV (N = 12), sexual partners of PLHIV (N = 5), and staff members (N = 6) of a Voluntary Counseling and Testing (VCT) center in Kerman located in the southeast of Iran. Our data collection included purposive sampling to increase variation. The content analysis was conducted using the Graneheim and Lundman approach. The analysis yielded 221 (out of 322) related codes related to HIV notification, its barriers, and its facilitators. These codes were further categorized into one main category with three categories and nine sub-categories. Results: The main category was HIV notification approaches, HIV notification barriers, and facilitators. HIV notification approaches were notification through clear, and direct conversation, notification through gradual preparation and reassurance, notification due to being with PLHIV, notification through suspicious talking of the physician, and notification due to the behavior of others. Also, the barriers were classified into individual, social, and environmental, and healthcare system barriers and the facilitators were at PLHIV, healthcare staff, and community levels. Stigma was a barrier mentioned by most participants. Also, the main facilitator of HIV notification was social support, especially from the family side. Conclusions: The findings highlighted the multidimensionality of HIV notification emphasizing the importance of tailored support and education to enhance the notification process for PLHIV and their networks. Also, our results show that despite all the efforts to reduce stigma and discrimination in recent years, stigma still exists as a main obstacle to disclosing HIV status and other barriers are the product of stigma. It seems that all programs should be directed towards destigmatization. [ABSTRACT FROM AUTHOR]

Introduction: The traditional approach to epidemic control has been to slow down the rate of infection while building up healthcare capacity, resulting in a flattened epidemic curve. Advancements in bio-information-communication technology (BICT) have enabled the preemptive isolation of infected cases through efficient testing and contact tracing. This study aimed to conceptualize the BICT-enabled epidemic control (BICTEC) and to document its relationships with epidemic curve shaping and epidemic mitigation performance. Methods: Daily COVID-19 incidences were collected from outbreak to Aug. 12, 2020, for nine countries reporting the first outbreak on or before Feb. 1, 2020. Key epidemic curve determinants–peak height (PH), time to peak (TTP), and area under the curve (AUC)–were estimated for each country, and their relationships were analyzed to test if epidemic curves peak quickly at a shorter height. CFR (Case Fatality Rate) and CI (Cumulative Incidence) were compared across the countries to identify relationships between epidemic curve shapes and epidemic mitigation performance. Results: China and South Korea had the quickest TTPs (40.70 and 45.37 days since outbreak, respectively) and the shortest PHs (2.95 and 4.65 cases per day, respectively). Sweden, known for its laissez-faire approach, had the longest TTP (120.36) and the highest PH (279.74). Quicker TTPs were correlated with shorter PHs (ρ = 0·896, p = 0·0026) and lower AUCs (0.790, p = 0.0028), indicating that epidemic curves do not follow a flattened trajectory. During the study period, countries with quicker TTPs tended to have lower CIs (ρ =.855, P =.006) and CFRs (ρ = 0.684, P =.061). For example, South Korea, with the second-quickest TTP, reported the second lowest CI and the lowest CFR. Conclusions: Countries that experienced early COVID-19 outbreaks demonstrated the epidemic curves that quickly peak at a shorter height, indicating a departure from the traditional flattened trajectory. South Korea's BICTEC was found to be at least as effective as most lockdowns in reducing CI and CFR. [ABSTRACT FROM AUTHOR]

Digital Contact Tracing (DCT) has been proved to be an effective tool to counteract the new SARS-CoV-2 or Covid-19. Despite this widespread effort to adopt the DCT, less attention has been paid to the organisation of the health logistics system that should support the tracing activities. Actually, the DCT poses a challenge to the logistics of the local health system in terms of number of daily tests to be collected and evaluated, especially when the spreading of the virus is soaring. In this paper we introduce a new optimisation problem called the Daily Swab Test Collection (DSTC) problem, that is the daily problem of collecting swab tests at home in such a way to guarantee a timely testing to people notified by the app to be in contact with a positive case. The problem is formulated as a variant of the team orienteering problem. The contributions of this paper are the following: (i) the new optimisation problem DSTC that complements and improves the DCT approach proposed by Ferretti et al. (Science https://doi.org/10.1126/science.abb6936, 2020), (ii) the DSCT formulation as a variant of the TOP and a literature review highlighting that this variant can have useful application in healthcare management, (iii) new realistic benchmark instances for the DSTC based on the city of Turin, (iv) two new efficient and effective hybrid algorithms capable to deal with realistic instances, (v) the managerial insights of our approach with a special regard on the fairness of the solutions. The main finding is that it possible to optimise the underlying logistics system in such a way to guarantee a timely testing to people recognised by the DCT. [ABSTRACT FROM AUTHOR]

The COVID-19 outbreak led governmental officials to close many businesses and schools, including colleges and universities. Thus, the ability to resume normal campus operation required adoption of safety measures to monitor and respond to COVID-19. The objective of this study was to determine the efficacy of wastewater-based epidemiology as a surveillance method in monitoring COVID-19 on a college campus. The use of wastewater monitoring as part of a surveillance program to control COVID-19 outbreaks at East Carolina University was evaluated. During the Spring and Fall 2021 semesters, wastewater samples (N = 830) were collected every Monday, Wednesday, and Friday from the sewer pipes exiting the dormitories on campus. Samples were analyzed for SARS-CoV-2 and viral quantification was determined using qRT-PCR. During the Spring 2021 semester, there was a significant difference in SARS-CoV-2 virus copies in wastewater when comparing dorms with the highest number student cases of COVID-19 and those with the lowest number of student cases, (p = 0.002). Additionally, during the Fall 2021 semester it was observed that when weekly virus concentrations exceeded 20 copies per ml, there were new confirmed COVID-19 cases 85% of the time during the following week. Increases in wastewater viral concentration spurred COVID-19 swab testing for students residing in dormitories, aiding university officials in effectively applying COVID testing policies. This study showed wastewater-based epidemiology can be a cost-effective surveillance tool to guide other surveilling methods (e.g., contact tracing, nasal/salvia testing, etc.) to identify and isolate afflicted individuals to reduce the spread of pathogens and potential outbreaks within a community. [ABSTRACT FROM AUTHOR]

Quantifying transmission intensity and heterogeneity is crucial to ascertain the threat posed by infectious diseases and inform the design of interventions. Methods that jointly estimate the reproduction number R and the dispersion parameter k have however mainly remained limited to the analysis of epidemiological clusters or contact tracing data, whose collection often proves difficult. Here, we show that clusters of identical sequences are imprinted by the pathogen offspring distribution, and we derive an analytical formula for the distribution of the size of these clusters. We develop and evaluate an inference framework to jointly estimate the reproduction number and the dispersion parameter from the size distribution of clusters of identical sequences. We then illustrate its application across a range of epidemiological situations. Finally, we develop a hypothesis testing framework relying on clusters of identical sequences to determine whether a given pathogen genetic subpopulation is associated with increased or reduced transmissibility. Our work provides tools to estimate the reproduction number and transmission heterogeneity from pathogen sequences without building a phylogenetic tree, thus making it easily scalable to large pathogen genome datasets. [ABSTRACT FROM AUTHOR]

In the early months of the COVID-19 pandemic, European countries implemented several non-pharmaceutical interventions with country-specific policies and reduced coordination. Digital Contact Tracing (DCT) was one of the few interventions on which European countries had a common approach oriented toward DCT apps' interoperability. As most EU countries implemented interoperable apps relying on an Apple and Google's framework, France developed the app autonomously. Recent literature argues that France's choice was mainly due to its strong stance in defense of national digital sovereignty. However, current contributions do not largely cover the issue empirically. Therefore, we aim to better explore the role played by digital sovereignty in the political debate related the development of DCT apps. To do so, we conducted a thematic analysis of 16 documents from France's political bodies, selected from a larger corpus of 438 documents dealing with DCT. Three main relevant dimensions related to digital sovereignty emerge. First, the initially sponsored EU interoperability progressively faded in the French political debate. Then, Apple and Google's involvement in the healthcare domain was perceived as highly problematic. Finally, having national players developing the DCT app was largely preferred. Based on our empirical findings, we further engaged with the concept of digital sovereignty, pointing out its difference from digital sovereignism by highlighting the ontological distinction between practices and ideas. Building on these reflections, we argue that France's stance towards DCT and the related digital sovereignty practices subtended digital sovereignism positions. [ABSTRACT FROM AUTHOR]

Background: Following the first locally transmitted case in Sukhbaatar soum, Selenge Province, we aimed to investigate the ultimate scale of the epidemic in the scenario of uninterrupted transmission. Methods: This was a prospective case study following the locally modified WHO FFX cases generic protocol. A rapid response team collected data from November 14 to 29, 2020. We created a stochastic process to draw many transmission chains from this greater distribution to better understand and make inferences regarding the outbreak under investigation. Results: The majority of the cases involved household transmissions (35, 52.2%), work transmissions (20, 29.9%), index (5, 7.5%), same apartment transmissions (2, 3.0%), school transmissions (2, 3.0%), and random contacts between individuals transmissions (1, 1.5%). The posterior means of the basic reproduction number of both the asymptomatic cases R0Asy$$ {R}_0^{Asy} $$ and the presymptomatic cases R0Pre$$ {R}_0^{Pre} $$ (1.35 [95% CrI 0.88–1.86] and 1.29 [95% CrI 0.67–2.10], respectively) were lower than that of the symptomatic cases (2.00 [95% Crl 1.38–2.76]). Conclusion: Our study highlights the heterogeneity of COVID‐19 transmission across different symptom statuses and underscores the importance of early identification and isolation of symptomatic cases in disease control. Our approach, which combines detailed contact tracing data with advanced statistical methods, can be applied to other infectious diseases, facilitating a more nuanced understanding of disease transmission dynamics. [ABSTRACT FROM AUTHOR]

Background: Digital contact tracing (DCT) was a central component of the global response to containing COVID‐19. Research has raised concerns that DCT could exacerbate inequities, yet the experiences of diverse communities at greater risk from COVID‐19 are typically underrepresented. Methods: The present study aimed to understand the perceived barriers to the adoption of the app amongst Māori, Pasifika, and disabled people. Focus groups and interviews were undertaken with Māori, Pasifika, and disability sector stakeholders and community participants. Results: Participants (n = 34) generally expressed willingness to utilise DCT and support its adoption within the communities. Simultaneously, participants revealed how the app could marginalise community members who struggled with the usability and those distrusting of the government's COVID‐19 interventions. Conclusions: The findings highlight how addressing communication inequality can assist in the development of contact‐tracing responses that are both effective and equitable. The study provides insights about the role of information and communication technologies as health resources. Patient or Public Contribution: Consulting with members of the target communities was central throughout the present study, including recommendations for potential participants, participation in interviews and sharing early findings for feedback. This study reports on focus groups and interviews with individuals from Māori and disability sectors. [ABSTRACT FROM AUTHOR]

The adoption of COVID-19 contact tracing apps (CTAs) has been proposed as an important measure to contain the spread of COVID-19. Based on a cross-national dataset, this article analyzes public perceptions toward CTAs and the factors that drive CTA acceptance in China, Germany, and the United States. We find that public acceptance of CTAs is significantly higher in China as compared with Germany and the United States. Despite very different sociopolitical contexts, there are striking similarities in the factors that drive CTA acceptance in all three countries. Citizens are willing to accept digital contact tracing despite concerns about privacy infringement and government surveillance, as long as the apps are perceived as effective in lowering infection rates and providing health information. This creates a chicken-and-egg problem for CTAs in Germany and the United States where CTAs are voluntary: a high citizen adoption rate is necessary for CTAs to be effective, but CTAs are only effective if adoption rates are high. [ABSTRACT FROM AUTHOR]

Background: During the COVID-19 pandemic, effective contact tracing was recognized as a crucial public health response to mitigate the spread of SARS-CoV-2 and reduce COVID-19-related morbidity and mortality, particularly before widespread vaccination. The World Health Organization (WHO) recommended implementing active surveillance strategies to trace and quarantine contacts of confirmed or suspected COVID-19 cases. Methods: A detailed review and analysis of the COVID-19 contact tracing responses was conducted in five European countries and territories, between March 2021 and August 2022. The countries and territories were selected to ensure geographical representation across the WHO European Region and applied a mixed-methods approach of in-depth interviews with various stakeholders across different administrative levels to identify good practices in COVID-19 contact tracing. The interviews covered 12 themes, including methods and procedures for COVID-19 contact tracing, information technology, quality assurance and key performance indicators. Results: The findings demonstrate that the policy approach, digitalization capabilities and implementation approach varied in the countries and territories and were dynamic throughout the pandemic. The analysis revealed that some practices were applicable across all countries and territories, while others were context-specific, catering to each country's and territory's unique needs. The study highlighted a need for all countries to institutionalize contact tracing as an essential function of existing health systems, to digitalize contact tracing practices and processes, and to build and retain contact tracing capacities for better pandemic preparedness. Conclusion: The lessons related to COVID-19 contact tracing should be utilized to strengthen future outbreak response operations as part of epidemic and pandemic preparedness. [ABSTRACT FROM AUTHOR]

COVID-19 and associated policy responses created unique social, economic and health risks for sex workers. Through semi-structured interviews we explored pre- and early COVID-19 experiences and work practices of ten cisgender female sex workers 50 years of age and older in Queensland, Australia, analysing the findings using a risk environment framework. Throughout early 2020, participants navigated a complex risk environment, managing economic needs, health and safety, occupational stigma and policing. Australia's policy responses altered the risks and opportunities available to participants. Half the participants continued sex work and half stopped sex work with some accessing economic support and withdrawing superannuation savings. Those who continued sex work drew on life and work experience to reassess changing health, stigma, and policing risks, and adapted their work strategies by increasing client screening and modifying services. Participants relied on information from peer networks and organisations to guide work practices but remained wary of contact tracing, police and the media. Decriminalisation of sex work and the strengthening of sex worker organisation and government partnerships are important in embedding equity in responses to ongoing and new public health threats. [ABSTRACT FROM AUTHOR]

OBJECTIVES: PNS is critical to prevent the spread of STIs. We evaluated the feasibility of integrating PNS into an STI clinic focused on MSM. DESIGN/METHODS: The RI STI Clinic, in partnership with the RIDOH, implemented a PNS program in 2019. Interviews with patients diagnosed with gonorrhea/syphilis were conducted. RIDOH attempted outreach to partners identified. We utilized interview data among MSM diagnosed with gonorrhea/syphilis in clinic from 1/1/19-12/31/2021. Bivariate analyses/multivariable logistic regression were conducted. RESULTS: 341 MSM were diagnosed with gonorrhea/syphilis during the three-year period, and 233 (68%) interviews were completed. Partner information was provided in 173 (74%) interviews. At least one workable partner was provided in 110 (47%) interviews. No statistically significant associations between provision of workable partners and index patient age/race/ethnicity were found. CONCLUSIONS: PNS at an STI clinic was successful, but challenges led to suboptimal information. Research is needed to identify barriers to integrate/optimize PNS in STI clinics. [ABSTRACT FROM AUTHOR]

With the outbreak of COVID-19 pandemic, contact tracing and social distance monitoring have been increasingly popular due to their capability of avoiding the spread of infectious diseases in communities. For the purpose, many studies investigate the contact events among moving objects (e.g., pedestrians, bicycles). In this light, we define the problem of Frequent Contact Detection (FCD) of moving objects on road networks. The FCD problem aims to find all frequent contact events among moving objects in a time period. We develop a two-phase solution, including contact search and frequent contact event discovery, to answer the FCD problem. For contact search, we develop the Search By Neighbor (SBN) framework and a pre-checking strategy to reduce the computation cost and further improve the efficiency of contact search. For frequent contact event discovery, we use categorized contact event set to find the objects that may form frequent contact events. Extensive experiments conducted on the two real datasets confirm the effectiveness and efficiency of our proposed solutions. [ABSTRACT FROM AUTHOR]

Background: Pakistan witnessed five waves of COVID-19 infections during the pandemic. Punjab, the largest province of Pakistan, remained the epicentre due to a high infection rate. Administrative data for five waves of the pandemic was analyzed to determine the rate of infections and the significance of pharmacological and non-pharmacological interventions on the severity and duration of infection. Methodology: COVID-19 data from March 2020 to May 2023 was obtained from the Provincial Public Health Reference Laboratory (PPHRL), Punjab AIDS Control Program, Lahore. The data included samples from index cases, contacts, and recovered patients. A total of 36,252,48 cases were screened for COVID-19, and 90,923 (2.50%) were detected positive by RT-PCR, accounting for 5.69% of the cases reported positive throughout the country. Results: Among the positive cases, 50.86% (n = 46,244) cases were new cases (registered for the first time), 40.41% (n = 36751) were the contact cases traced from the newly identified cases and 8.62% (n = 7842) repeated cases. The positivity rates among index cases were reported to be 2.37%, 2.34%, 4.61%, 2.09%, and 1.19%, respectively, for the five respective COVID-19 pandemic waves. Distribution by gender indicated that 64% of males and 35% of females were infected during the pandemic. The age factor demonstrated the most susceptibility to infection in women aged 19-29 years, whereas most males between the ages of 29-39 had an infection. Susceptibility to COVID-19 infection was observed to be equally likely between males and females; however, clinical outcomes indicated that infections in males were more severe and often resulted in fatalities as compared to those in females. This trend was also reflected in the viral titer as measured by the Ct values, where 40% of males had Ct values < 25 (an indicator of high viral titers) compared to 30% of females with Ct values < 25. Conclusion: Overall, our data indicated that infection rates remained stable throughout the pandemic except for 3rd wave, which showed a higher incidence of infection rate of 4%. Additionally, data showed a positive impact of masking, social distancing, and immunization, as indicated by the shorter window of high infection rates. [ABSTRACT FROM AUTHOR]

Background: Taiwan was a coronavirus disease 2019 (COVID-19) outlier, with an extraordinarily long transmission-free record: 253 days without locally transmitted infections while the rest of the world battled wave after wave of infection. The appearance of the alpha variant in May 2021, closely followed by the delta variant, disrupted this transmission-free streak. However, despite low vaccination coverage (<1%), outbreaks were well-controlled. Methods: This study analyzed the time to border closure and conducted one-sample t test to compare between Taiwan and Non-Taiwan countries prior to vaccine introduction. The study also collected case data to observe the dynamics of omicron transmission. Time-varying reproduction number,Rt, was calculated and was used to reflect infection impact at specified time points and model trends of future incidence. Results: The study analyzed and compare the time to border closure in Taiwan and non-Taiwan countries. The mean times to any border closure from the first domestic case within each country were -21 and 5.98 days, respectively (P <.0001). The Taiwanese government invested in quick and effective contact tracing with a precise quarantine strategy in lieu of a strict lockdown. Residents followed recommendations based on self-discipline and unity. The self-discipline in action is evidenced in Google mobility reports. The central and local governments worked together to enact non-pharmaceutical interventions (NPIs), including universal masking, social distancing, limited unnecessary gatherings, systematic contact tracing, and enhanced quarantine measures. The people cooperated actively with pandemic-prevention regulations, including vaccination and preventive NPIs. Conclusions: This article describes four key factors underlying Taiwan's success in controlling COVID-19 transmission: quick responses; effective control measures with new technologies and rolling knowledge updates; unity and cooperation among Taiwanese government agencies, private companies and organizations, and individual citizens; and Taiwanese self-discipline. [ABSTRACT FROM AUTHOR]

Background: Early during the COVID-19 pandemic, it was important to better understand transmission dynamics of SARS-CoV-2, the virus that causes COVID-19. Household contacts of infected individuals are particularly at risk for infection, but delays in contact tracing, delays in testing contacts, and isolation and quarantine posed challenges to accurately capturing secondary household cases. Methods: In this study, 346 households in the Seattle region were provided with respiratory specimen collection kits and remotely monitored using web-based surveys for respiratory illness symptoms weekly between October 1, 2020, and June 20, 2021. Symptomatic participants collected respiratory specimens at symptom onset and mailed specimens to the central laboratory in Seattle. Specimens were tested for SARS-CoV-2 using RT-PCR with whole genome sequencing attempted when positive. SARS-CoV-2-infected individuals were notified, and their household contacts submitted specimens every 2 days for 14 days. Results: In total, 1371 participants collected 2029 specimens that were tested; 16 individuals (1.2%) within 6 households tested positive for SARS-CoV-2 during the study period. Full genome sequences were generated from 11 individuals within 4 households. Very little genetic variation was found among SARS-CoV-2 viruses sequenced from different individuals in the same household, supporting transmission within the household. Conclusions: This study indicates web-based surveillance of respiratory symptoms, combined with rapid and longitudinal specimen collection and remote contact tracing, provides a viable strategy to monitor households and detect household transmission of SARS-CoV-2. Trial registration identifier: NCT04141930, Date of registration 28/10/2019. [ABSTRACT FROM AUTHOR]

Isolating COVID-19 cases and quarantining their close contacts can prevent COVID-19 transmissions but also inflict harm. We analysed isolation and quarantine orders by the local public health agency in Berlin-Reinickendorf (Germany) and their dependence on the recommendations by the Robert Koch Institute, the national public health institute. Between 3 March 2020 and 18 December 2021 the local public health agency ordered 24 603 isolations (9.2 per 100 inhabitants) and 45 014 quarantines (17 per 100 inhabitants) in a population of 266 123. The mean contacts per case was 1.9. More days of quarantine per 100 inhabitants were ordered for children than for adults: 4.1 for children aged 0-6, 5.2 for children aged 7-17, 0.9 for adults aged 18-64 and 0.3 for senior citizens aged 65-110. The mean duration for isolation orders was 10.2 and for quarantine orders 8.2 days. We calculated a delay of 4 days between contact and quarantine order. 3484 contact persons were in quarantine when they developed an infection. This represents 8% of all individuals in quarantine and 14% of those in isolation. Our study quantifies isolation and quarantine orders, shows that children had been ordered to quarantine more than adults and that there were fewer school days lost to isolation or quarantine as compared to school closures. Our results indicate that the recommendations of the Robert Koch Institute had an influence on isolation and quarantine duration as well as contact identification and that the local public health agency was not able to provide rigorous contact tracing, as the mean number of contacts was lower than the mean number of contacts per person known from literature. Additionally, a considerable portion of the population underwent isolation or quarantine, with a notable number of cases emerging during the quarantine period. [ABSTRACT FROM AUTHOR]

Background: HIV mostly affects people with severe mental illnesses (SMIs) than the general population. In 2015, the World Health Organization (WHO) introduced assisted partner notification (APN) as a strategy to increase HIV testing. Although research has demonstrated the effectiveness of APN in the general population, its use among people living with HIV (PLHIV) who have SMI is not well understood. This study sought to determine the acceptance of the APN strategy among PLHIV who had a diagnosis of SMI. Methods: This study used a cross-sectional study design that was retrospective to determine acceptance of APN among PLHIV with a documented diagnosis of SMI. We enrolled participants with a diagnosis of both HIV and SMI from August 2018 to January 2022, attending the HIV clinic at Butabika Hospital. We used pretested questionnaires to extract participants' demographic and clinical data from their existing clinical charts, antiretroviral therapy (ART) registers and APN registers. We defined acceptance of APN as the number of PLHIV with SMI diagnoses who agreed to provide information about their sexual partners. We used modified Poisson regression analysis to assess the factors associated with the acceptance of APN. Results: A total of 125 participants were enrolled, of whom 83 (66.4%) were female. The median age was 30 (interquartile range (IQR) (25–34)), and 41 (33%) of them accepted APN (95% CI: 25.05–41.61). Receipt of at least three counselling sessions before enrollment in APN (aPR = 1.8, 95% CI: 1.72–1.98) was the most significant factor associated with increased acceptance of APN. Poor adherence to ART (aPR = 0.62, 95% CI: 0.54–0.80), being escorted to hospital by a distant relative (aPR = 0.55, 95% CI: 0.39–0.80), being married/cohabiting (aPR = 0.65, 95% CI: 0.60–0.81), and being a Seventh Day Adventist (SDA) (aPR = 0.53, 95% CI: 0.45–0.71) or Pentecostal (aPR = 0.44, 95% CI: 0.22–0.98) by faith were associated with reduced acceptance of APN. Conclusion and recommendation: The acceptance of APN is low among PLHIV with a diagnosis of SMI. More structured counselling would facilitate earlier identification of undiagnosed HIV-positive partners. We recommend a follow-up study to compare acceptance of APN among PLHIV with SMI and those without SMI. [ABSTRACT FROM AUTHOR]

Background: Contact tracing is a key component in controlling the spread of COVID-19, however little research has focused on learning from the experiences of contact tracing staff. Harnessing learning from those in this role can provide valuable insights into the process of contact tracing and how best to support staff in this crucial role. Methods: Thematic analysis was used to analyse 47 semi-structured interviews conducted with contact tracing staff via telephone or Zoom at three time points in 2021: March, May and September-October. Results: Six themes related to the contact tracing role were identified, including training, workforce culture, systems issues, motivation and support. While initially nervous in the role, participants were motivated to contribute to the pandemic response and believed the role provided them with valuable transferable skills. Participants described the training as having improved over time while desiring more proactive training. Sources of frustration included a perceived lack of opportunity for feedback and involvement in process changes, feelings of low autonomy, and a perception of high staff turnover. Participants expressed a need for improved communication of formal emotional supports. Increased managerial support and provision of opportunities for career advancement may contribute to increased motivation among staff. Conclusions: These findings identify the experiences of contact tracing staff working during the COVID-19 pandemic, and have important implications for the improvement of the contact tracing system. Recommendations based on learning from participants offer suggestions as to how best to support the needs of contact tracing staff during a pandemic response. [ABSTRACT FROM AUTHOR]

Background: HIV mostly affects people with severe mental illnesses (SMIs) than the general population. In 2015, the World Health Organization (WHO) introduced assisted partner notification (APN) as a strategy to increase HIV testing. Although research has demonstrated the effectiveness of APN in the general population, its use among people living with HIV (PLHIV) who have SMI is not well understood. This study sought to determine the acceptance of the APN strategy among PLHIV who had a diagnosis of SMI. Methods: This study used a cross-sectional study design that was retrospective to determine acceptance of APN among PLHIV with a documented diagnosis of SMI. We enrolled participants with a diagnosis of both HIV and SMI from August 2018 to January 2022, attending the HIV clinic at Butabika Hospital. We used pretested questionnaires to extract participants' demographic and clinical data from their existing clinical charts, antiretroviral therapy (ART) registers and APN registers. We defined acceptance of APN as the number of PLHIV with SMI diagnoses who agreed to provide information about their sexual partners. We used modified Poisson regression analysis to assess the factors associated with the acceptance of APN. Results: A total of 125 participants were enrolled, of whom 83 (66.4%) were female. The median age was 30 (interquartile range (IQR) (25–34)), and 41 (33%) of them accepted APN (95% CI: 25.05–41.61). Receipt of at least three counselling sessions before enrollment in APN (aPR = 1.8, 95% CI: 1.72–1.98) was the most significant factor associated with increased acceptance of APN. Poor adherence to ART (aPR = 0.62, 95% CI: 0.54–0.80), being escorted to hospital by a distant relative (aPR = 0.55, 95% CI: 0.39–0.80), being married/cohabiting (aPR = 0.65, 95% CI: 0.60–0.81), and being a Seventh Day Adventist (SDA) (aPR = 0.53, 95% CI: 0.45–0.71) or Pentecostal (aPR = 0.44, 95% CI: 0.22–0.98) by faith were associated with reduced acceptance of APN. Conclusion and recommendation: The acceptance of APN is low among PLHIV with a diagnosis of SMI. More structured counselling would facilitate earlier identification of undiagnosed HIV-positive partners. We recommend a follow-up study to compare acceptance of APN among PLHIV with SMI and those without SMI. [ABSTRACT FROM AUTHOR]

Background: We aimed at evaluating the diagnostic performance of rapid antigen test (RAT) compared to polymerase chain reaction (PCR) for severe acute respiratory syndrome coronavirus 2 and the possible transmission of infection to close contacts from patients with negative RAT and positive PCR results. Materials and Methods: Patients/guardians urgently requiring admission to the ward on the same day had been hospitalized with RAT-negative result before the PCR results were available. We performed an epidemiologic investigation of the close contacts of those with negative RAT but positive PCR results after hospitalization. Results: A total of 4,237 RATs were performed from March to August 2022. When the PCR test was used as the reference, RAT had a sensitivity of 28.8% (17/59; 95% confidence interval [CI], 17.8 - 42.1), a specificity of 100% (4,220/4,220; 95% CI, 99.9 – 100.0), a positive predictive value of 100.0% (17/17; 95% CI, 100.0 - 100.0), and a negative predictive value of 99.0% (4,178/4,220; 95% CI, 99.3 - 99.8). The epidemiologic investigation revealed that among the 32 patients with negative RAT and subsequent positive PCR results after admission into multi-patient room, two (6.3%) showed secondary coronavirus disease 2019. Conclusion: The secondary transmission rate from patients with negative RAT and positive PCR results was low. Our data suggest that RAT may be useful for rapid exclusion of high transmissible cases. However, further evaluation using whole genome sequencing is needed to determine the potential for transmissibility in cases showing a negative RAT but a positive PCR result. [ABSTRACT FROM AUTHOR]

OBJECTIVE: The total annual count of reported tuberculosis (TB) cases continues to decline throughout Turkey. Recognizing the regions with high and low burdens and revealing the factors affecting TB notification rates may play a role in guiding national control programs. This study aimed to analyze the spatial distribution of TB notification rates from 2005 to 2018 and evaluate the factors contributing to TB rates. MATERIAL AND METHODS: In this ecological study, we used freely available open data from the Internet. We employed global and local spatial autocorrelation analysis to identify the spatial distribution and the clusters with low and high burdens. We conducted an ordinary least square regression model, spatial lag model, and spatial error model. The best-fitting model was selected via model parameters. RESULTS: Throughout the study period, the provinces in West Marmara Region (Edirne, Kırklareli, Tekirdağ, Çanakkale) were consistently in a high-burden cluster. In univariate ordinary least square regression, population density, the proportion of contacts screened for TB, the proportion of TB contacts who received prophylaxis, TB dispensary count, mean particulate matter 10 levels, and gross domestic product were found to be positively associated with TB notification rate. The best-fitting multivariate spatial lag model revealed that the proportion of contacts screened for TB (ß, z-value: 0.89, 2.21) positively affected TB notification rate. CONCLUSION: The high TB burden in West Marmara Region should warn policymakers to maintain a focused approach to controlling TB in this area. This study showed the importance of contact tracing efforts to prevent the underdetection of TB cases. [ABSTRACT FROM AUTHOR]

The intensity of exposure to index cases of tuberculosis [TB] may increase the risk of TB in their contacts. The aim was to determine TB risk factors among contacts of TB index cases. A cohort study was carried out in the contacts of pulmonary TB cases registered by the epidemiological surveillance network from 01/01/2019 to 06/30/2021. The factors associated with the risk of TB in contacts were determined using the adjusted odds ratio [aOR] and its 95% confidence interval [CI]. From 847 TB cases, 7087 contacts were identified. The prevalence of TB was 2.0% [145/7087] and was higher in < 5 years compared to those ≥ 65 years [4.4% versus 1.2%; p < 0.001], in those exposed ≥ 6 h daily [4%], and < 6 h daily [1.6%] with respect to weekly exposure of < 6 h [0.7%; p < 0.001]. Those contacts exposed ≥ 6 h daily [aOR= 6.9; 95%CI:2.1–22.1], < 5 years [aOR= 8.3; 95%CI:1.8–37.8] and immigrants [aOR= 1.7; 95%CI:1.1–2.7] had a higher risk of TB. The risk of TB increases with the time of exposure to the index case and this risk is also higher in < 5 years and immigrants. Contact tracing has a high yield for detecting new cases of TB. [ABSTRACT FROM AUTHOR]

During 2022, a global outbreak of mpox resulted primarily from human-to-human contact. The Virginia Department of Health (Richmond, VA, USA) implemented a contact tracing and symptom monitoring system for residents exposed to monkeypox virus, assessed their risk for infection, and offered interventions as needed. Among 991 contacts identified during May 1--November 1, 2022, import records were complete for 943 (95.2%), but 99 (10.0%) were not available for follow-up during symptom monitoring. Mpox developed in 28 (2.8%) persons; none were healthcare workers exposed at work (n = 275). Exposure risk category and likelihood of developing mpox were strongly associated. A total of 333 persons received >1 dose of JYENNOS (Bavarian Nordic, https://www.bavarian-nordic.com) vaccine, most (n = 295) administered after virus exposure. Median time from exposure to vaccination was 8 days. Those data tools provided crucial real-time information for public health responses and can be used as a framework for other emerging diseases. [ABSTRACT FROM AUTHOR]

Background: India achieved the elimination of leprosy two decades ago although its sustenance continues to be threatened by ongoing active transmission in few remaining pockets. There is a paucity of data regarding the acceptance of single-dose rifampicin (SDR) prophylaxis among healthy contacts. Aims and Objectives: The aims and objectives of the study are to assess the factors influencing the acceptability of SDR among contacts. Materials and Methods: A community-based, sequential, explanatory mixedmethod study was conducted over 6 months from September 2022 to February 2023 among 168 contacts of leprosy patients from two blocks in Bankura district, West Bengal. Quantitative analysis was done for SDR acceptance and its predictors among contacts using the Chi-square test, Mann–Whitney U test, and Logistic regression. This was followed by qualitative assessment using focus group discussions and in-depth interviews among contacts to explain the findings through a thematic approach. Results: Household contacts (aOR=13.72, 95% CI=2.09–90.19), increasing knowledge score of contacts (aOR=3.18, 95% CI=1.88–5.38), counseling by health workers (aOR=11.98, 95% CI=2.20–65.15), trust in health workers (aOR=152.96, 95% CI=13.17–1776.09), and not taking other medicines for comorbidity (aOR=35.82, 95% CI=2.94–436.02) were associated with increased SDR uptake among leprosy contacts. Barriers and facilitators of post-exposure prophylaxis (PEP)-SDR were categorized as contact, health workers, and program-related factors. Conclusion: SDR acceptability among contacts was 77.4%. Facilitators of SDR-PEP were awareness of side-effects, follow-up, prompt support by health workers, IEC, belief in National programs, etc. Lack of knowledge of PEP-SDR and contraindications, ineffective counseling by health workers, stigma of the disease, the increased workload of health workers, etc., were the barriers to SDR-PEP implementation. [ABSTRACT FROM AUTHOR]

In this article, we explore Quick Response (QR) codes (machine-readable optical labels that link to information) and how, after a period of having fallen out of favor, they have been reactivated and have come to underpin COVID-19 automation and contact-tracing efforts. During the pandemic, they were used especially for "safe entry" and other kinds of check-in to locations to facilitate contact tracing. In this context, QR codes facilitate automated decision-making in relation to infectious disease surveillance and disease outbreak control. However, the use of QR codes for contact-tracing purposes has enjoyed mixed success and its implementation has encountered several challenges, as we illustrate through a case study that explores QR codes and COVID contact tracing in Singapore and Australia. [ABSTRACT FROM AUTHOR]

The pandemic response was a thoroughly mediated phenomenon – one that paired digital information technologies with automated logistical systems to address inter-related crises of circulation. In the logistical sphere, automated media were used to manage flows of people, commodities and even (in the case of 'smart' ventilation systems) air itself. In the media realm, automated systems played a role in circulating timely notifications and alerts and in detecting and responding to false information. This theme issue brings together an interdisciplinary group of researchers focused on the analysis of automated control and response systems, including the networked devices and infrastructures that supported them, and the digital forms of data collection and processing they enabled. This introductory essay focuses on some organizing themes that emerge from the theme issue contributions, including the relationship between automation and the temporality of viral contagion, logics of pre-emptive intervention and forms of atmospheric and environmental control. [ABSTRACT FROM AUTHOR]

In this paper, we develop an epidemic model with a nonlinear function that describes the saturated digital contact tracing. The model is theoretically and numerically analyzed based on its dynamics. The model equilibria points and the basic reproduction number are obtained. However, the proposed model reveals both backward and forward bifurcation, and backward bifurcation occurs when the digital contact tracing saturation parameter is larger than a specific threshold. Real data are used to fit the model and estimate the parameter values. Sensitivity analysis reveals that interventions such as reducing the infection rate, enhancing quarantine efforts, and accelerating vaccination can effectively reduce the basic reproduction number, R 0 . Simulations show that improving tracing accuracy and encouraging greater participation in providing personal track information can effectively reduce the peak of undetected exposed individuals. Moreover, we analyze the expression for the specific threshold and determine that the increasing hospital resources and strengthening patient quarantine can reduce the potential occurrence of backward bifurcation. The analysis and simulations presented in this paper provide valuable suggestions for the prevention and control of the epidemic. [ABSTRACT FROM AUTHOR]

This article offers a critical analysis of China's health code system, a data-powered pandemic control and contact tracing system that supposedly subjects all individuals in the country to its panopticon control, a surveillance system that monitors and categorises the Chinese population into the healthy (green), the dubious (yellow), and the unhealthy (red). The article highlights the pretence of surveillance as care and the digital divide that normalises discrimination against the elderly and other digitally left-behind population. It also illustrates how, from policy making and technological design to user engagement, the health code system is implemented, optimised, and used in everyday life to meet the needs of the vulnerable population. The health code is better taken as a medium of adaptable and communicative process that can reset the relation between the system and the lifeworld. It is the process of interchange between the system and the lifeworld that deserves our critical attention. [ABSTRACT FROM AUTHOR]

Objective To assess the outcomes of a contact-tracing programme to increase the diagnosis of tuberculosis in Cubal, Angola and offer preventive treatment to high-risk groups. Methods A health centre-based contact-tracing programme was launched in Hospital Nossa Senhora da Paz in March 2015 and we followed the programme until 2022. In that time, staffing and testing varied which we categorized as four periods: medical staff reinforcement, 2015-2017, with a doctor seconded from Vall d'Hebron University Hospital, Spain; routine staff, 2017-2021, with no external medical support; community directly observed treatment (DOT), 2018-2019 with community worker support; and enhanced contact tracing, 2021-2022, with funding that allowed free chest radiographs, molecular and gastric aspirate testing. We assessed differences in contacts seen each month, and testing and treatment offered across the four periods. Findings Overall, the programme evaluated 1978 contacts from 969 index cases. Participation in the programme was low, although it increased significantly during the community DOT period. Only 16.6% (329/1978) of contacts had a chest radiograph. Microbiological confirmation increased to 72.2% (26/36) after including molecular testing, and 10.1% (200/1978) of contacts received treatment for tuberculosis. Of 457 contacts younger than 5 years, 36 (7.9%) received preventive tuberculosis treatment. Half of the contacts were lost to follow-up before a final decision was taken on treatment. Conclusion Contact tracing increased the diagnosis of tuberculosis although engagement with the programme was low and loss to followup was high. Participation increased during community DOT. Community-based screening should be explored to improve participation and diagnosis. [ABSTRACT FROM AUTHOR]

This article frames the action imperative as an ethical dilemma for governance actors. It situates the debate in the context of the design and implementation of digital contact tracing applications to mitigate the spread of the COVID-19 pandemic. Using a normative case study approach, it seeks to answer the question—how can the ethical dilemma of an action imperative in the face of scientific and normative uncertainty, be resolved by governance actors in ways that can minimize harms? Drawing insights from the field of Science and Technology Studies, this article makes the case that when scientific evidence claims are weak, the action imperative should follow a cascade of deference with objectivity, consensus, precaution, and subsidiarity as stopping points. It concludes by making a broader case to promote moral reasoning concerning the substantive goals of digitalization. [ABSTRACT FROM AUTHOR]

Objective: Publication science is the scholarly study of various aspects of the academic publishing process. Its applications to COVID-19 literature have been limited. Here, we describe COVID-19 submissions to, and resulting articles published by, the journal Public Health Reports (PHR), an important resource for US public health practice. Methods: We reviewed PHR 's COVID-19 submissions and articles published between March 27, 2020, and March 27, 2023. We coded each article for article type, author affiliation, the categories listed in PHR 's call for COVID-19 papers, and the public health emergency preparedness and response capabilities from the Centers for Disease Control and Prevention (CDC). Results: During the study period, PHR received 1545 COVID-19 submissions and published 190 of those articles in a collection, COVID-19 Response. The COVID-19 Response collection included 102 research articles, 29 case study/practice articles, and 24 commentaries. The corresponding author of more than half (52.1%; n = 99) of the articles was affiliated with academia. By the categories listed in PHR 's call for COVID-19 papers, 51 articles addressed health disparities, 38 addressed public health surveillance, and 34 addressed COVID-19 vaccination. By the CDC public health emergency preparedness and response capabilities, 87 articles addressed public health surveillance and epidemiologic investigation, 38 addressed community preparedness, and 32 addressed community recovery. The percentage of articles focused on policy/law was higher early in the pandemic (2020-2021) than later (2022-2023) (9.5% vs <3.0%). During the latter period, articles largely focused on vaccination (12.8%) and contact tracing (10.6%). Conclusions: Articles published in PHR 's COVID-19 Response collection covered a broad range of topics and were authored by contributors from diverse organizations. Our characterization of the COVID-19 output of a representative US public health practice journal can help academic publishing better address informational needs of public health responders. [ABSTRACT FROM AUTHOR]

In this research, we present the first steps toward developing a data-driven agent-based model (ABM) specifically designed for simulating infectious disease dynamics in Greece. Amidst the ongoing COVID-19 pandemic caused by SARS-CoV-2, this research holds significant importance as it can offer valuable insights into disease transmission patterns and assist in devising effective intervention strategies. To the best of our knowledge, no similar study has been conducted in Greece. We constructed a prototype ABM that utilizes publicly accessible data to accurately represent the complex interactions and dynamics of disease spread in the Greek population. By incorporating demographic information and behavioral patterns, our model captures the specific characteristics of Greece, enabling accurate and context-specific simulations. By using our proposed ABM, we aim to assist policymakers in making informed decisions regarding disease control and prevention. Through the use of simulations, policymakers have the opportunity to explore different scenarios and predict the possible results of various intervention measures. These may include strategies like testing approaches, contact tracing, vaccination campaigns, and social distancing measures. Through these simulations, policymakers can assess the effectiveness and feasibility of these interventions, leading to the development of well-informed strategies aimed at reducing the impact of infectious diseases on the Greek population. This study is an initial exploration toward understanding disease transmission patterns and a first step towards formulating effective intervention strategies for Greece. [ABSTRACT FROM AUTHOR]

Background: The aim of our study was to test the hypothesis that the community contact tracing strategy of testing contacts in households immediately instead of at the end of quarantine had an impact on the transmission of SARS-CoV-2 in schools in Reggio Emilia Province. Methods: We analysed surveillance data on notification of COVID-19 cases in schools between 1 September 2020 and 4 April 2021. We have applied a mediation analysis that allows for interaction between the intervention (before/after period) and the mediator. Results: Median tracing delay decreased from 7 to 3.1 days and the percentage of the known infection source increased from 34-54.8% (incident rate ratio-IRR 1.61 1.40-1.86). Implementation of prompt contact tracing was associated with a 10% decrease in the number of secondary cases (excess relative risk -0.1 95% CI -0.35-0.15). Knowing the source of infection of the index case led to a decrease in secondary transmission (IRR 0.75 95% CI 0.63-0.91) while the decrease in tracing delay was associated with decreased risk of secondary cases (1/IRR 0.97 95% CI 0.94-1.01 per one day of delay). The direct effect of the intervention accounted for the 29% decrease in the number of secondary cases (excess relative risk -0.29 95%-0.61 to 0.03). Conclusions: Prompt contact testing in the community reduces the time of contact tracing and increases the ability to identify the source of infection in school outbreaks. Although there are strong reasons for thinking it is a causal link, observed differences can be also due to differences in the force of infection and to other control measures put in place. Funding: This project was carried out with the technical and financial support of the Italian Ministry of Health - CCM 2020 and Ricerca Corrente Annual Program 2023. [ABSTRACT FROM AUTHOR]

Contact tracing forms a crucial part of the public-health toolbox in mitigating and understanding emergent pathogens and nascent disease outbreaks. Contact tracing in the United States was conducted during the pre-Omicron phase of the ongoing COVID-19 pandemic. This tracing relied on voluntary reporting and responses, often using rapid antigen tests due to lack of accessibility to PCR tests. These limitations, combined with SARS-CoV-2's propensity for asymptomatic transmission, raise the question "how reliable was contact tracing for COVID-19 in the United States"? We answered this question using a Markov model to examine the efficiency with which transmission could be detected based on the design and response rates of contact tracing studies in the United States. Our results suggest that contact tracing protocols in the U.S. are unlikely to have identified more than 1.65% (95% uncertainty interval: 1.62-1.68%) of transmission events with PCR testing and 1.00% (95% uncertainty interval 0.98-1.02%) with rapid antigen testing. When considering a more robust contact tracing scenario, based on compliance rates in East Asia with PCR testing, this increases to 62.7% (95% uncertainty interval: 62.6-62.8%). We did not assume presence of asymptomatic transmission or superspreading, making our estimates upper bounds on the actual percentages traced. These findings highlight the limitations in interpretability for studies of SARS-CoV-2 disease spread based on U.S. contact tracing and underscore the vulnerability of the population to future disease outbreaks, for SARS-CoV-2 and other pathogens. [ABSTRACT FROM AUTHOR]

The coronavirus disease 2019 (COVID-19) presents a severe and urgent threat to global health. In response to the COVID-19 pandemic, many countries have implemented nonpharmaceutical interventions (NPIs), including national workplace and school closures, personal protection, social distancing, contact tracing, testing, home quarantine, and isolation. To evaluate the effectiveness of these NPIs in mitigating the spread of early COVID-19 and predict the epidemic trend in the United Kingdom, we developed a compartmental model to mimic the transmission with time-varying transmission rate, contact rate, disease-induced mortality rate, proportion of quarantined close contacts, and hospitalization rate. The model was fitted to the number of confirmed new cases and daily number of deaths in five stages with a Markov Chain Monte Carlo method. We quantified the effectiveness of NPIs and found that if the transmission rate, contact rate, and hospitalization rate were approximately equal to those in the second stage of the most strict NPIs, and the proportion of quarantined close contacts increased by 3%, then the epidemic would die out as early as January 12, 2021, with around 1,533,000 final cumulative number of confirmed cases, and around 55,610 final cumulative number of deaths. [ABSTRACT FROM AUTHOR]

A rapid and affordable point-of-care test is a priority for Neisseria gonorrhoeae control. WHO and Foundation for Innovative New Diagnostics (FIND) have a target product profile for a non-molecular N gonorrhoeae rapid point-of-care test that requires a clinical sensitivity of greater than 80% and a specificity over 95% to be considered useful in syndromic management; test turnaround time should be 30 min or under, and the test should cost less than US$3. A novel lateral flow assay (LFA) was developed to achieve that profile. In this cross-sectional study we evaluated the performance of the novel N gonorrhoeae lateral flow assay (NG-LFA) at the primary health-care level in South Africa. Male patients with urethral discharge syndrome and female patients with vaginal discharge syndrome were recruited from five primary health-care facilities in the Buffalo City Metropolitan Municipality health district of South Africa. First-void urine specimens and nurse-collected vaginal swabs were tested in-facility with the NG-LFA and Xpert CT/NG PCR assay. N gonorrhoeae multi-antigen sequence typing (NG-MAST) was performed on all LFA positive specimens. Between March 7, and Sept 19, 2022, we enrolled 200 male patients with urethral discharge and 200 female patients with vaginal discharge. The median age of male patients was 24 years (IQR 21–31 years), and the median age of female patients was 25 years (IQR 21–32 years). In addition, 23 male patients and 12 female patients who presented at the facility with a partner notification slip were enrolled of whom one (4%) and five (42%) were symptomatic, respectively. NG-LFA and Xpert results were available for all participants. In urine specimens, NG-LFA sensitivity was 96·1% (Wilson 95% CI 91·2–98·3; 123 LFA-positive among 128 PCR-positive specimens) and 91·7% in vaginal swab specimens (78·2–97·1; 33 LFA-positive among 36 PCR-positive). The specificity was 97·2% in urine specimens (90·4–99·2; 70 LFA-negative among 72 PCR-negative) and 96·3% in vaginal specimens (92·2–98·3; 158 LFA-negative among 164 PCR-negative). In 156 LFA-positive specimens, NG-MAST showed 93 different sequence types. The novel NG-LFA had excellent clinical sensitivity and specificity in symptomatic male and female patients. The test met the optimal requirement for sensitivity and the minimal requirement for specificity specified in the target product profile. NG-LFA could provide an important tool to optimise clinical management and reduce excess antibiotic use in settings without direct access to laboratory testing. Global Antimicrobial Resistance Innovation Fund (GAMRIF) via FIND and National Institutes of Health. [ABSTRACT FROM AUTHOR]

Background Universities returned to in-person learning in 2021 while SARS-CoV-2 spread remained high. At the time, it was not clear whether in-person learning would be a source of disease spread. Methods We combined surveillance testing, universal contact tracing, and viral genome sequencing to quantify introductions and identify likely on-campus spread. Results Ninety-one percent of viral genotypes occurred once, indicating no follow-on transmission. Less than 5% of introductions resulted in >3 cases, with 2 notable exceptions of 40 and 47 cases. Both partially overlapped with outbreaks defined by contact tracing. In both cases, viral genomics eliminated over half the epidemiologically linked cases but added an equivalent or greater number of individuals to the transmission cluster. Conclusions Public health interventions prevented within-university transmission for most SARS-CoV-2 introductions, with only 2 major outbreaks being identified January to May 2021. The genetically linked cases overlap with outbreaks identified by contact tracing; however, they persisted in the university population for fewer days and rounds of transmission than estimated via contact tracing. This underscores the effectiveness of test-trace-isolate strategies in controlling undetected spread of emerging respiratory infectious diseases. These approaches limit follow-on transmission in both outside-in and internal transmission conditions. [ABSTRACT FROM AUTHOR]

Importance: Contact tracing is the process of identifying people who have recently been in contact with someone diagnosed with an infectious disease. During an outbreak, data collected from contact tracing can inform interventions to reduce the spread of infectious diseases. Understanding factors associated with completion rates of contact tracing surveys can help design improved interview protocols for ongoing and future programs. Objective: To identify factors associated with completion rates of COVID-19 contact tracing surveys in New York City (NYC) and evaluate the utility of a predictive model to improve completion rates, we analyze laboratory-confirmed and probable COVID-19 cases and their self-reported contacts in NYC from October 1st 2020 to May 10th 2021. Methods: We analyzed 742,807 case investigation calls made during the study period. Using a log-binomial regression model, we examined the impact of age, time of day of phone call, and zip code-level demographic and socioeconomic factors on interview completion rates. We further developed a random forest model to predict the best phone call time and performed a counterfactual analysis to evaluate the change of completion rates if the predicative model were used. Results: The percentage of contact tracing surveys that were completed was 79.4%, with substantial variations across ZIP code areas. Using a log-binomial regression model, we found that the age of index case (an individual who has tested positive through PCR or antigen testing and is thus subjected to a case investigation) had a significant effect on the completion of case investigation – compared with young adults (the reference group,24 years old < age < = 65 years old), the completion rate for seniors (age > 65 years old) were lower by 12.1% (95%CI: 11.1% – 13.3%), and the completion rate for youth group (age < = 24 years old) were lower by 1.6% (95%CI: 0.6% –2.6%). In addition, phone calls made from 6 to 9 pm had a 4.1% (95% CI: 1.8% – 6.3%) higher completion rate compared with the reference group of phone calls attempted from 12 and 3 pm. We further used a random forest algorithm to assess its potential utility for selecting the time of day of phone call. In counterfactual simulations, the overall completion rate in NYC was marginally improved by 1.2%; however, certain ZIP code areas had improvements up to 7.8%. Conclusion: These findings suggest that age and time of day of phone call were associated with completion rates of case investigations. It is possible to develop predictive models to estimate better phone call time for improving completion rates in certain communities. [ABSTRACT FROM AUTHOR]

Background: It is not yet fully understood to what extent in-flight transmission contributed to the spread of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). This study aimed to determine the occurrence and extent of SARS-CoV-2 transmission in-flight and assess factors associated with transmission risk to inform future control strategies. Methods: Retrospective cohort study using data obtained from contact tracing of international flights arriving in England between 02/08/2021–15/10/2021. Transmission risk was estimated by calculating the secondary attack rate (SAR). Univariable and multivariable analyses of the SAR by specific risk factors was undertaken, including: number of in-flight index cases; number of symptomatic index cases; contact vaccination status; flight duration; proximity to the index case(s); contact age. Results: 11,307 index cases linked to 667,849 contacts with 5,289 secondary cases reported. In-flight SAR was 0.79% (95% CI: 0.77–0.81). Increasing numbers of symptomatic cases (when > 4 index cases compared to one index case aOR 1.85; 95% CI: 1.40–2.44) and seating proximity to an index case (seated within compared to outside of two rows OR 1.82; 95% CI: 1.50–2.22) were associated with increased risk of secondary cases. Full vaccination history was protective (aOR 0.52; 95% CI: 0.47–0.57). Conclusions: This study confirms that in-flight transmission of SARS-CoV-2 occurred. There are factors associated with increased risk of infection. Contact tracing identified exposed persons who subsequently developed infection. A targeted approach to contact tracing passengers with the highest exposure risk could be an effective use of limited public health resources. [ABSTRACT FROM AUTHOR]

Objectives: Limited evidence exists on the policies to increase self‐isolation compliance, with no experimental evidence. This trial aimed to evaluate the effect of a home visiting intervention in the London Borough of Havering on compliance with self‐isolation guidance, relative to positive COVID‐19 cases who received no home visits. Design: Mixed method evaluation involving a two‐arm randomized controlled trial (RCT) with an implementation and process evaluation. Methods: A total of 3878 cases who tested positive for COVID‐19 were randomly allocated with equal probability to receive home visits from Havering outreach team staff (n = 1946) or to a control group (n = 1932) who did not receive home visits. Randomization was implemented through a spreadsheet consisting of random numbers generated online that was used to randomly allocate cases to treatment and control. Check‐in calls were conducted by a separate blinded contact tracing team on day six of isolation to measure successful self‐isolation compliance. The primary intention‐to‐treat (ITT) analysis was conducted on 3860 cases as 18 patients were excluded from analysis because of the missing outcome data. For the implementation and process evaluation, qualitative, semi‐structured, one‐to‐one interviews were conducted with trial participants in the treatment arm of the RCT (n = 15) and stakeholders within the London Borough of Havering's Adult Social Care and Health Team (n = 8). Qualitative data was analysed thematically using a framework approach. Results: Positive cases who were allocated to receive the home visiting intervention (n = 1933) were more likely to report successful self‐isolation compared to those allocated to the control group (n = 1927), an effect that was statistically significant (odds ratio 1.204 [95% CI: 1.052, 1.377]; absolute probability difference: 4.1 percentage points [95% CI: 1.2–6.9]). The implementation and process evaluation found that a key driver of compliance was altruistic motivation based on its perceived importance for protecting the community with some participants also reporting the potential of being caught not complying as a driving factor. Participants also reported that the intervention helped them 'feel supported', provided them with information about practical and financial support, and clarified their understanding or increased their awareness of self‐isolation and COVID‐19 guidance. No harms were reported from this trial. The trial was registered at the ISRCTN registry, number ISRCTN10030612. Conclusions: A home‐visiting intervention conducted between January and March 2022 increased the self‐isolation compliance of positive COVID‐19 cases allocated to receive home visits. The implementation and process evaluation highlighted that the intervention increased individuals' motivation to comply with guidance, and addressed some barriers associated with opportunity and capability to comply. This trial provides much‐needed evidence to inform the policy and intervention design to support public health and social measures in future outbreak scenarios. [ABSTRACT FROM AUTHOR]

Background Many hospitals caring for adult patients have discontinued the requirement for contact precautions (CP) for patients with methicillin-resistant Staphylococcus aureus (MRSA) infection or colonization without reported negative effects. It is not clear whether this experience can be extrapolated to pediatric facilities. Methods CP for MRSA were discontinued in all locations except the neonatal intensive care unit at a 3-hospital pediatric healthcare system in September 2019. All hospitalized patients underwent surveillance for LabID healthcare facility-onset MRSA infections. Analysis was done using interrupted time series (ITS) from September 2017 through August 2023 and aggregate before-and-after rate ratios. Results There were 234 incident healthcare facility-onset MRSA infections during 766 020 patient days of surveillance. After discontinuation of CP for MRSA there was no change in the ITS slope (0.06, 95% CI: −0.35 to 0.47, P  = .78) or intercept (0.21, 95% CI: −0.36 to 0.78, P  = .47) of the LabID healthcare facility-onset MRSA infection incidence density rate. Additionally, there was no change in the aggregate incidence density rate of these MRSA LabID events (aggregate rate ratio = 0.98, 95% CI: 0.74 to 1.28). MRSA nasal colonization among patients being screened before cardiac surgery did not change (aggregate rate ratio = 0.94, 95% CI: 0.60 to 1.48). The prevalence rate of contact isolation days decreased by 14.0%. Conclusions Discontinuation of CP for pediatric patients with MRSA was not associated with increased MRSA infection over 4 years. Our experience supports considering discontinuation of CP for MRSA in similar pediatric healthcare settings in the context of good adherence to horizontal infection prevention measures. [ABSTRACT FROM AUTHOR]

Childhood tuberculosis remains a major cause of morbidity and mortality in part due to missed diagnosis. Diagnostic methods with enhanced sensitivity using easy-to-obtain specimens are needed. We aimed to assess the diagnostic accuracy of the Cepheid Mycobacterium tuberculosis Host Response prototype cartridge (MTB-HR), a candidate test measuring a three-gene transcriptomic signature from fingerstick blood, in children with presumptive tuberculosis disease. RaPaed-TB was a prospective diagnostic accuracy study conducted at four sites in African countries (Malawi, Mozambique, South Africa, and Tanzania) and one site in India. Children younger than 15 years with presumptive pulmonary or extrapulmonary tuberculosis were enrolled between Jan 21, 2019, and June 30, 2021. MTB-HR was performed at baseline and at 1 month in all children and was repeated at 3 months and 6 months in children on tuberculosis treatment. Accuracy was compared with tuberculosis status based on standardised microbiological, radiological, and clinical data. 5313 potentially eligible children were screened, of whom 975 were eligible. 784 children had MTB-HR test results, of whom 639 had a diagnostic classification and were included in the analysis. MTB-HR differentiated children with culture-confirmed tuberculosis from those with unlikely tuberculosis with a sensitivity of 59·8% (95% CI 50·8–68·4). Using any microbiological confirmation (culture, Xpert MTB/RIF Ultra, or both), sensitivity was 41·6% (34·7–48·7), and using a composite clinical reference standard, sensitivity was 29·6% (25·4–34·2). Specificity for all three reference standards was 90·3% (95% CI 85·5–94·0). Performance was similar in different age groups and by malnutrition status. Among children living with HIV, accuracy against the strict reference standard tended to be lower (sensitivity 50·0%, 15·7–84·3) compared with those without HIV (61·0%, 51·6–69·9), although the difference did not reach statistical significance. Combining baseline MTB-HR result with one Ultra result identified 71·2% of children with microbiologically confirmed tuberculosis. MTB-HR showed promising diagnostic accuracy for culture-confirmed tuberculosis in this large, geographically diverse, paediatric cohort and hard-to-diagnose subgroups. European and Developing Countries Clinical Trials Partnership, UK Medical Research Council, Swedish International Development Cooperation Agency, Bundesministerium für Bildung und Forschung; German Center for Infection Research (DZIF). [ABSTRACT FROM AUTHOR]

Because of constrained personnel time, the Philadelphia Department of Public Health (Philadelphia, PA, USA) adjusted its COVID-19 contact tracing protocol in summer 2021 by prioritizing recent cases and limiting staff time per case. This action reduced required staff hours to prevent each case from 21-30 to 8-11 hours, while maintaining program effectiveness. [ABSTRACT FROM AUTHOR]

Based on differential geometry and gear meshing theory, a meshing model of working pitch cone and pitch cylinder of crossed beveloid gear and involute cylindrical gear transmission was established for geometric parameter design. The mounting parameters of gear pair were derived, with the addition of tooth surface equation of beveloid gear and involute cylindrical gear obtained by hobbing process, tooth contact analysis (TCA) was performed. The changes of contact trace, contact ellipse and principal curvature of gear pair under different geometric parameters were investigated, then the accuracy of results was verified by loaded tooth contact analysis (LTCA). The results show that the contact region of gear pair is significantly influenced by shaft angle and cone angle of beveloid gear. The principal curvature at contact points of the gear pair is relatively sensitive to the cone angle of beveloid gear. Moreover, the length of contact trace is strongly influenced by geometric parameters. [ABSTRACT FROM AUTHOR]