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1.
Mayo Clin Proc ; 96(6): 1592-1608, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34088418

RESUMO

The coronavirus disease 2019 (COVID-19) pandemic continues its global spread. Coordinated effort on a vast scale is required to halt its progression and to save lives. Electronic health record (EHR) data are a valuable resource to mitigate the COVID-19 pandemic. We review how the EHR could be used for disease surveillance and contact tracing. When linked to "omics" data, the EHR could facilitate identification of genetic susceptibility variants, leading to insights into risk factors, disease complications, and drug repurposing. Real-time monitoring of patients could enable early detection of potential complications, informing appropriate interventions and therapy. We reviewed relevant articles from PubMed, MEDLINE, and Google Scholar searches as well as preprint servers, given the rapidly evolving understanding of the COVID-19 pandemic.


Assuntos
COVID-19/epidemiologia , Registros Eletrônicos de Saúde , COVID-19/diagnóstico , COVID-19/prevenção & controle , Busca de Comunicante/métodos , Reposicionamento de Medicamentos , Monitoramento Epidemiológico , Humanos , SARS-CoV-2/genética
2.
An. pediatr. (2003. Ed. impr.) ; 94(5): 318-326, mayo 2021. tab
Artigo em Espanhol | IBECS | ID: ibc-196939

RESUMO

INTRODUCCIÓN: Ante la posible coexistencia de la infección por el virus SARS-CoV-2 con otras infecciones estacionales, se pretende identificar síntomas diferenciales. Se ha estudiado el papel de los niños en el contagio intrafamiliar y la sensibilidad de la reacción en cadena de la polimerasa con transcriptasa inversa (RT-PCR) en un área con baja transmisión comunitaria. MATERIAL Y MÉTODOS: Estudio observacional transversal. Pacientes entre 0-15 años estudiados por técnica RT-PCR por sospecha clínica de infección por virus SARS-CoV-2 en los meses de marzo-mayo del 2020. Encuesta sobre síntomas y contactos. Determinación de anticuerpos anti-SARS-CoV-2 al menos 21 días después del test RT- PCR. RESULTADOS: Se incluyó a 126 pacientes, 33 con infección confirmada y edad media 8,4 años (IC del 95%, 6,8-10,0) superior a los no infectados. La fiebre fue el síntoma más común y con mayor sensibilidad. Las diferencias encontradas fueron una mayor frecuencia de anosmia (p = 0,029) y cefalea (p = 0,009) entre los niños infectados con una especificidad del 96,7 y el 81,5% respectivamente. No hubo diferencias en la duración de los síntomas. Un 81,8% de los infectados fue probablemente contagiado en el núcleo familiar, en un 85,2% por un progenitor que trabajaba fuera del hogar. La sensibilidad de RT-PCR fue 70,9% y su valor predictivo negativo 91,1%. CONCLUSIONES: El cuadro clínico es inespecífico y los síntomas más específicos difíciles de detectar en niños más pequeños. Los niños tuvieron un papel reducido en la transmisión intrafamiliar. La sensibilidad de la RT-PCR podría estar relacionada con una menor contagiosidad infantil tras una semana de infección


INTRODUCTION: Given the possible coexistence of infection by the SARS-CoV-2 with other seasonal infections, the aim is to identify differential symptoms. I know has studied the role of children in intrafamily contagion and the sensitivity of reverse transcriptase polymerase chain reaction (RT-PCR) in an area with low community transmission. MATERIAL AND METHODS: Cross-sectional observational study. Patients between 0-15 years studied by RT-PCR technique due to clinical suspicion of infection by SARS-CoV-2 virus in the months of March-May 2020. Survey on symptoms and contacts. Determination of Anti-SARS-CoV-2 antibodies at least 21 days after the RT-PCR test. RESULTS: 126 patients were included, 33 with confirmed infection and age mean 8.4 years (95% CI 6.8-10,5) higher than not infected. Fever was the most common and with greater sensitivity. The differences found were a greater frequency of anosmia (P = 0.029) and headache (P = .009) among children infected with a specificity of 96.7% and 81.5% respectively. There were no differences in the duration of the symptoms. 81.8% of those infected were probably infected in the nucleus 85.2% by a parent who worked outside the home. The sensitivity of RT-PCR was 70.9% and its negative predictive value 91.1%. CONCLUSIONS: The clinical picture is nonspecific and the symptoms more specific difficult to detect in younger children. Children had a reduced role in the intrafamily transmission. The sensitivity of RT-PCR could be related to a less contagiousness in children after one week of infection


Assuntos
Humanos , Masculino , Feminino , Recém-Nascido , Lactente , Pré-Escolar , Busca de Comunicante/métodos , Busca de Comunicante/estatística & dados numéricos , Infecções por Coronavirus/transmissão , Pneumonia Viral/transmissão , Infecções por Coronavirus/diagnóstico , Pneumonia Viral/diagnóstico , Pandemias , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Sensibilidade e Especificidade , Diagnóstico Diferencial , Estudos Transversais
3.
JAMA Netw Open ; 4(5): e218824, 2021 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-33938934

RESUMO

Importance: Schools were closed intermittently across Hong Kong to control the COVID-19 outbreak, which led to significant physical and psychosocial problems among children and youths. Objective: To compare the clinical characteristics and sources of infection among children and youths with COVID-19 during the 3 waves of outbreaks in Hong Kong in 2020. Design, Setting, and Participants: This cross-sectional study involved children and youths aged 18 years or younger with COVID-19 in the 3 waves of outbreaks from January 23 through December 2, 2020. Data were analyzed from December 2020 through January 2021. Main Outcomes and Measures: Demographic characteristics, travel and contact histories, lengths of hospital stay, and symptoms were captured through the central electronic database. Individuals who were infected without recent international travel were defined as having domestic infections. Results: Among 397 children and youths confirmed with COVID-19 infections, the mean (SD) age was 9.95 (5.34) years, 220 individuals (55.4%) were male, and 154 individuals (38.8%) were asymptomatic. There were significantly more individuals who were infected without symptoms in the second wave (59 of 118 individuals [50.0%]) and third wave (94 of 265 individuals [35.5%]) than in the first wave (1 of 14 individuals [7.1%]) (P = .001). Significantly fewer individuals who were infected in the second and third waves, compared with the first wave, had fever (first wave: 10 individuals [71.4%]; second wave: 22 individuals [18.5%]; third wave: 98 individuals [37.0%]; P < .001) or cough (first wave: 6 individuals [42.9%]; second wave: 15 individuals [12.7%]; third wave: 52 individuals [19.6%]; P = .02). Among all individuals, 394 individuals (99.2%) had mild illness. One patient developed chilblains (ie, COVID toes), 1 patient developed multisystem inflammatory syndrome in children, and 1 patient developed post-COVID-19 autoimmune hemolytic anemia. In all 3 waves, 204 patients with COVID-19 (51.4%) had domestic infections. Among these individuals, 186 (91.2%) reported having a contact history with another individual with COVID-19, of which most (183 individuals [90.0%]) were family members. In the third wave, 18 individuals with domestic infections had unknown contact histories. Three schoolmates were confirmed with COVID-19 on the same day and were reported to be close contacts. Conclusions and Relevance: This cross-sectional study found that nearly all children and youths with COVID-19 in Hong Kong had mild illness. These findings suggest that household transmission was the main source of infection for children and youths with domestic infections and that the risk of being infected at school was small.


Assuntos
Infecções Assintomáticas/epidemiologia , Busca de Comunicante , Avaliação de Sintomas , Adolescente , /terapia , Criança , Busca de Comunicante/métodos , Busca de Comunicante/estatística & dados numéricos , Estudos Transversais , Transmissão de Doença Infecciosa/prevenção & controle , Transmissão de Doença Infecciosa/estatística & dados numéricos , Características da Família , Feminino , Hong Kong/epidemiologia , Hospitalização/estatística & dados numéricos , Humanos , Masculino , Índice de Gravidade de Doença , Avaliação de Sintomas/métodos , Avaliação de Sintomas/estatística & dados numéricos , Doença Relacionada a Viagens
4.
Sci Rep ; 11(1): 9414, 2021 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-33941793

RESUMO

To combat the COVID-19 pandemic, many countries around the globe have adopted digital contact tracing apps. Various technologies exist to trace contacts that are potentially prone to different types of tracing errors. Here, we study the impact of different proximity detection ranges on the effectiveness and efficiency of digital contact tracing apps. Furthermore, we study a usage stop effect induced by a false positive quarantine. Our results reveal that policy makers should adjust digital contact tracing apps to the behavioral characteristics of a society. Based on this, the proximity detection range should at least cover the range of a disease spread, and be much wider in certain cases. The widely used Bluetooth Low Energy protocol may not necessarily be the most effective technology for contact tracing.


Assuntos
/transmissão , Busca de Comunicante/métodos , Aplicativos Móveis , Humanos , Pandemias , Privacidade , Quarentena , Tecnologia
5.
Sci Adv ; 7(19)2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33962957

RESUMO

Nonpharmaceutical interventions to control SARS-CoV-2 spread have been implemented with different intensity, timing, and impact on transmission. As a result, post-lockdown COVID-19 dynamics are heterogeneous and difficult to interpret. We describe a set of contact surveys performed in four Chinese cities (Wuhan, Shanghai, Shenzhen, and Changsha) during the pre-pandemic, lockdown and post-lockdown periods to quantify changes in contact patterns. In the post-lockdown period, the mean number of contacts increased by 5 to 17% as compared to the lockdown period. However, it remains three to seven times lower than its pre-pandemic level sufficient to control SARS-CoV-2 transmission. We find that the impact of school interventions depends nonlinearly on the intensity of other activities. When most community activities are halted, school closure leads to a 77% decrease in the reproduction number; in contrast, when social mixing outside of schools is at pre-pandemic level, school closure leads to a 5% reduction in transmission.


Assuntos
/epidemiologia , Busca de Comunicante/estatística & dados numéricos , Pandemias/prevenção & controle , Quarentena , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , China/epidemiologia , Cidades/epidemiologia , Busca de Comunicante/métodos , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Inquéritos e Questionários , Adulto Jovem
6.
PLoS One ; 16(5): e0251867, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33989350

RESUMO

Contact tracing has historically been used to retard the spread of infectious diseases, but if it is exercised by hand in large-scale, it is known to be a resource-intensive and quite deficient process. Nowadays, digital contact tracing has promptly emerged as an indispensable asset in the global fight against the coronavirus pandemic. The work at hand offers a meticulous study of all the official Android contact tracing apps deployed hitherto by European countries. Each app is closely scrutinized both statically and dynamically by means of dynamic instrumentation. Depending on the level of examination, static analysis results are grouped in two axes. The first encompasses permissions, API calls, and possible connections to external URLs, while the second concentrates on potential security weaknesses and vulnerabilities, including the use of trackers, in-depth manifest analysis, shared software analysis, and taint analysis. Dynamic analysis on the other hand collects data pertaining to Java classes and network traffic. The results demonstrate that while overall these apps are well-engineered, they are not free of weaknesses, vulnerabilities, and misconfigurations that may ultimately put the user security and privacy at risk.


Assuntos
/epidemiologia , Busca de Comunicante/métodos , Aplicativos Móveis , Pandemias/prevenção & controle , /virologia , Segurança Computacional , Europa (Continente)/epidemiologia , Humanos , Privacidade
7.
Philos Trans R Soc Lond B Biol Sci ; 376(1829): 20200267, 2021 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-34053253

RESUMO

We explore strategies of contact tracing, case isolation and quarantine of exposed contacts to control the SARS-CoV-2 epidemic using a branching process model with household structure. This structure reflects higher transmission risks among household members than among non-household members. We explore strategic implementation choices that make use of household structure, and investigate strategies including two-step tracing, backwards tracing, smartphone tracing and tracing upon symptom report rather than test results. The primary model outcome is the effect of contact tracing, in combination with different levels of physical distancing, on the growth rate of the epidemic. Furthermore, we investigate epidemic extinction times to indicate the time period over which interventions must be sustained. We consider effects of non-uptake of isolation/quarantine, non-adherence, and declining recall of contacts over time. Our results find that, compared to self-isolation of cases without contact tracing, a contact tracing strategy designed to take advantage of household structure allows for some relaxation of physical distancing measures but cannot completely control the epidemic absent of other measures. Even assuming no imported cases and sustainment of moderate physical distancing, testing and tracing efforts, the time to bring the epidemic to extinction could be in the order of months to years. This article is part of the theme issue 'Modelling that shaped the early COVID-19 pandemic response in the UK'.


Assuntos
COVID-19/epidemiologia , Modelos Teóricos , Pandemias , SARS-CoV-2/patogenicidade , COVID-19/transmissão , COVID-19/virologia , Busca de Comunicante/métodos , Características da Família , Humanos , Quarentena/métodos
8.
AIDS Educ Prev ; 33(3): 234-248, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34014111

RESUMO

We explored interest in disclosing test results through a smartphone app dedicated to self- and partner testing for HIV/syphilis. Fifty-nine cisgender men and transgender women each participated in an in-person survey and interview. We examined their interests in sharing test results by audience (e.g., partners, physicians) and by positive versus negative test result. Participants wanted the ability to share results, with notable interest in disclosing negative results to sexual partners and on social media and forwarding positive results to physicians. Participants envisioned smartphone sharing as a means to normalize testing, to notify partners of results, and to expedite linkage to care. Some questioned the authenticity of results shared by smartphone, while others voiced optimism that a personalized, authenticated app could ensure the security and veracity of results. Smartphone testing apps for HIV/syphilis may facilitate disclosure, partner notification, and linkage to care, but need to address concerns about the security and veracity of results.


Assuntos
Busca de Comunicante/métodos , Infecções por HIV/diagnóstico , Conhecimentos, Atitudes e Prática em Saúde , Aplicativos Móveis , Parceiros Sexuais , Smartphone , Sífilis/diagnóstico , Revelação da Verdade , Adulto , Idoso , Feminino , Infecções por HIV/prevenção & controle , Infecções por HIV/psicologia , Humanos , Entrevistas como Assunto , Masculino , Pessoa de Meia-Idade , Percepção , Pesquisa Qualitativa , Sífilis/prevenção & controle , Sífilis/psicologia , Adulto Jovem
9.
JMIR Public Health Surveill ; 7(6): e27189, 2021 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-34003761

RESUMO

BACKGROUND: During the COVID-19 pandemic, swab tests proved to be effective in containing the infection and served as a means for early diagnosis and contact tracing. However, little evidence exists regarding the correct timing for the execution of the swab test, especially for asymptomatic individuals and health care workers. OBJECTIVE: The objective of this study was to analyze changes in the positive findings over time in individual SARS-CoV-2 swab tests during a health surveillance program. METHODS: The study was conducted with 2071 health care workers at the University Hospital of Verona, with a known date of close contact with a patient with COVID-19, between February 29 and April 17, 2020. The health care workers underwent a health surveillance program with repeated swab tests to track their virological status. A generalized additive mixed model was used to investigate how the probability of a positive test result changes over time since the last known date of close contact, in an overall sample of individuals who tested positive for COVID-19 and in a subset of individuals with an initial negative swab test finding before being proven positive, to assess different surveillance time intervals. RESULTS: Among the 2071 health care workers in this study, 191 (9.2%) tested positive for COVID-19, and 103 (54%) were asymptomatic with no differences based on sex or age. Among 49 (25.7%) cases, the initial swab test yielded negative findings after close contact with a patient with COVID-19. Sex, age, symptoms, and the time of sampling were not different between individuals with an initial negative swab test finding and those who initially tested positive after close contact. In the overall sample, the estimated probability of testing positive was 0.74 on day 1 after close contact, which increased to 0.77 between days 5 and 8. In the 3 different scenarios for scheduled repeated testing intervals (3, 5, and 7 days) in the subgroup of individuals with an initially negative swab test finding, the probability peaked on the sixth, ninth and tenth, and 13th and 14th days, respectively. CONCLUSIONS: Swab tests can initially yield false-negative outcomes. The probability of testing positive increases from day 1, peaking between days 5 and 8 after close contact with a patient with COVID-19. Early testing, especially in this final time window, is recommended together with a health surveillance program scheduled in close intervals.


Assuntos
Teste de Ácido Nucleico para COVID-19/estatística & dados numéricos , COVID-19/diagnóstico , Pessoal de Saúde/estatística & dados numéricos , Adulto , COVID-19/epidemiologia , COVID-19/transmissão , Busca de Comunicante/métodos , Reações Falso-Negativas , Feminino , Humanos , Transmissão de Doença Infecciosa do Paciente para o Profissional/estatística & dados numéricos , Itália/epidemiologia , Masculino , Pessoa de Meia-Idade , Pandemias , SARS-CoV-2 , Fatores de Tempo
10.
PLoS One ; 16(5): e0251242, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34014947

RESUMO

The SARS-CoV-2 pandemic led to closure of nearly all K-12 schools in the United States of America in March 2020. Although reopening K-12 schools for in-person schooling is desirable for many reasons, officials understand that risk reduction strategies and detection of cases are imperative in creating a safe return to school. Furthermore, consequences of reclosing recently opened schools are substantial and impact teachers, parents, and ultimately educational experiences in children. To address competing interests in meeting educational needs with public safety, we compare the impact of physical separation through school cohorts on SARS-CoV-2 infections against policies acting at the level of individual contacts within classrooms. Using an age-stratified Susceptible-Exposed-Infected-Removed model, we explore influences of reduced class density, transmission mitigation, and viral detection on cumulative prevalence. We consider several scenarios over a 6-month period including (1) multiple rotating cohorts in which students cycle through in-person instruction on a weekly basis, (2) parallel cohorts with in-person and remote learning tracks, (3) the impact of a hypothetical testing program with ideal and imperfect detection, and (4) varying levels of aggregate transmission reduction. Our mathematical model predicts that reducing the number of contacts through cohorts produces a larger effect than diminishing transmission rates per contact. Specifically, the latter approach requires dramatic reduction in transmission rates in order to achieve a comparable effect in minimizing infections over time. Further, our model indicates that surveillance programs using less sensitive tests may be adequate in monitoring infections within a school community by both keeping infections low and allowing for a longer period of instruction. Lastly, we underscore the importance of factoring infection prevalence in deciding when a local outbreak of infection is serious enough to require reverting to remote learning.


Assuntos
/transmissão , Busca de Comunicante/métodos , Pandemias , Vigilância da População/métodos , Instituições Acadêmicas , Adolescente , Criança , Humanos , Modelos Teóricos , Estados Unidos
11.
Nat Commun ; 12(1): 2993, 2021 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-34017008

RESUMO

Initial COVID-19 containment in the United States focused on limiting mobility, including school and workplace closures. However, these interventions have had enormous societal and economic costs. Here, we demonstrate the feasibility of an alternative control strategy, test-trace-quarantine: routine testing of primarily symptomatic individuals, tracing and testing their known contacts, and placing their contacts in quarantine. We perform this analysis using Covasim, an open-source agent-based model, which has been calibrated to detailed demographic, mobility, and epidemiological data for the Seattle region from January through June 2020. With current levels of mask use and schools remaining closed, we find that high but achievable levels of testing and tracing are sufficient to maintain epidemic control even under a return to full workplace and community mobility and with low vaccine coverage. The easing of mobility restrictions in June 2020 and subsequent scale-up of testing and tracing programs through September provided real-world validation of our predictions. Although we show that test-trace-quarantine can control the epidemic in both theory and practice, its success is contingent on high testing and tracing rates, high quarantine compliance, relatively short testing and tracing delays, and moderate to high mask use. Thus, in order for test-trace-quarantine to control transmission with a return to high mobility, strong performance in all aspects of the program is required.


Assuntos
/prevenção & controle , Busca de Comunicante/métodos , Quarentena/métodos , Humanos , Estados Unidos
12.
PLoS One ; 16(5): e0252019, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34019589

RESUMO

Against the current COVID-19 pandemic, governments worldwide have devised a variety of non-pharmaceutical interventions to mitigate it. However, it is generally difficult to estimate the joint impact of different control strategies. In this paper, we tackle this question with an extended epidemic SEIR model, informed by a socio-political classification of different interventions. First, we inquire the conceptual effect of mitigation parameters on the infection curve. Then, we illustrate the potential of our model to reproduce and explain empirical data from a number of countries, to perform cross-country comparisons. This gives information on the best synergies of interventions to control epidemic outbreaks while minimising impact on socio-economic needs. For instance, our results suggest that, while rapid and strong lockdown is an effective pandemic mitigation measure, a combination of social distancing and early contact tracing can achieve similar mitigation synergistically, while keeping lower isolation rates. This quantitative understanding can support the establishment of mid- and long-term interventions, to prepare containment strategies against further outbreaks. This paper also provides an online tool that allows researchers and decision makers to interactively simulate diverse scenarios with our model.


Assuntos
/epidemiologia , Busca de Comunicante/estatística & dados numéricos , Quarentena/estatística & dados numéricos , /prevenção & controle , Busca de Comunicante/métodos , Humanos , Modelos Estatísticos , Quarentena/métodos
13.
Lancet Digit Health ; 3(6): e383-e396, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33967002

RESUMO

Health information technology can support the development of national learning health and care systems, which can be defined as health and care systems that continuously use data-enabled infrastructure to support policy and planning, public health, and personalisation of care. The COVID-19 pandemic has offered an opportunity to assess how well equipped the UK is to leverage health information technology and apply the principles of a national learning health and care system in response to a major public health shock. With the experience acquired during the pandemic, each country within the UK should now re-evaluate their digital health and care strategies. After leaving the EU, UK countries now need to decide to what extent they wish to engage with European efforts to promote interoperability between electronic health records. Major priorities for strengthening health information technology in the UK include achieving the optimal balance between top-down and bottom-up implementation, improving usability and interoperability, developing capacity for handling, processing, and analysing data, addressing privacy and security concerns, and encouraging digital inclusivity. Current and future opportunities include integrating electronic health records across health and care providers, investing in health data science research, generating real-world data, developing artificial intelligence and robotics, and facilitating public-private partnerships. Many ethical challenges and unintended consequences of implementation of health information technology exist. To address these, there is a need to develop regulatory frameworks for the development, management, and procurement of artificial intelligence and health information technology systems, create public-private partnerships, and ethically and safely apply artificial intelligence in the National Health Service.


Assuntos
Sistema de Aprendizagem em Saúde , Informática Médica , Inteligência Artificial/tendências , Busca de Comunicante/métodos , Interoperabilidade da Informação em Saúde , Humanos , Aplicativos Móveis , Vigilância da População/métodos , Parcerias Público-Privadas , Robótica/tendências , Integração de Sistemas , Reino Unido
14.
PLoS Med ; 18(4): e1003585, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33930019

RESUMO

BACKGROUND: Test-trace-isolate programs are an essential part of coronavirus disease 2019 (COVID-19) control that offer a more targeted approach than many other nonpharmaceutical interventions. Effective use of such programs requires methods to estimate their current and anticipated impact. METHODS AND FINDINGS: We present a mathematical modeling framework to evaluate the expected reductions in the reproductive number, R, from test-trace-isolate programs. This framework is implemented in a publicly available R package and an online application. We evaluated the effects of completeness in case detection and contact tracing and speed of isolation and quarantine using parameters consistent with COVID-19 transmission (R0: 2.5, generation time: 6.5 days). We show that R is most sensitive to changes in the proportion of cases detected in almost all scenarios, and other metrics have a reduced impact when case detection levels are low (<30%). Although test-trace-isolate programs can contribute substantially to reducing R, exceptional performance across all metrics is needed to bring R below one through test-trace-isolate alone, highlighting the need for comprehensive control strategies. Results from this model also indicate that metrics used to evaluate performance of test-trace-isolate, such as the proportion of identified infections among traced contacts, may be misleading. While estimates of the impact of test-trace-isolate are sensitive to assumptions about COVID-19 natural history and adherence to isolation and quarantine, our qualitative findings are robust across numerous sensitivity analyses. CONCLUSIONS: Effective test-trace-isolate programs first need to be strong in the "test" component, as case detection underlies all other program activities. Even moderately effective test-trace-isolate programs are an important tool for controlling the COVID-19 pandemic and can alleviate the need for more restrictive social distancing measures.


Assuntos
/prevenção & controle , Busca de Comunicante , Surtos de Doenças/prevenção & controle , Modelos Teóricos , /diagnóstico , Busca de Comunicante/métodos , Humanos , Quarentena , /patogenicidade
15.
Travel Med Infect Dis ; 41: 102044, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33838318

RESUMO

BACKGROUND: Imported COVID-19 cases, if unchecked, can jeopardize the effort of domestic containment. We aim to find out what sustainable border control options for different entities (e.g., countries, states) exist during the reopening phases, given their own choice of domestic control measures. METHODS: We propose a SUIHR model, which has built-in imported risk and (1-tier) contact tracing to study the cross-border spreading and control of COVID-19. Under plausible parameter assumptions, we examine the effectiveness of border control policies, in combination with internal measures, to confine the virus and avoid reverting back to more restrictive life styles again. RESULTS: When the basic reproduction number R0 of COVID-19 exceeds 2.5, even 100% effective contact tracing alone is not enough to contain the spreading. For an entity that has completely eliminated the virus domestically, and resumes "normal", without mandatory institutional quarantine, even very strict border control measures combined with effective contact tracing can only delay another outbreak by 6 months. For entities employing a confining domestic control policy, non-increasing net imported cases is sufficient to remain open. CONCLUSIONS: Extremely strict border control in entities, where domestic spreading is currently eliminated (e.g., China), is justifiable. However such harsh measure are not necessary for other places. Entities successfully confining the virus by internal measures can open up to similar entities without additional border controls so long as the imported risk stays non-increasing. Opening the borders to entities lacking sufficient internal control of the virus should be exercised in combination with pre-departure screening and tests upon arrival.


Assuntos
/prevenção & controle , Controle de Doenças Transmissíveis/métodos , Política Pública , Viagem , Número Básico de Reprodução , /transmissão , Doenças Transmissíveis Importadas/epidemiologia , Doenças Transmissíveis Importadas/prevenção & controle , Doenças Transmissíveis Importadas/transmissão , Busca de Comunicante/métodos , Surtos de Doenças/prevenção & controle , Governo , Humanos , Modelos Teóricos , Pandemias/prevenção & controle , Quarentena/métodos
17.
PLoS One ; 16(4): e0249394, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33852588

RESUMO

INTRODUCTION: The reporting of Coronavirus Disease 19 (COVID-19) mortality among healthcare workers highlights their vulnerability in managing the COVID-19 pandemic. Some low- and middle-income countries have highlighted the challenges with COVID-19 testing, such as inadequate capacity, untrained laboratory personnel, and inadequate funding. This article describes the components and implementation of a healthcare worker surveillance programme in a designated COVID-19 teaching hospital in Malaysia. In addition, the distribution and characteristics of healthcare workers placed under surveillance are described. MATERIAL AND METHODS: A COVID-19 healthcare worker surveillance programme was implemented in University Malaya Medical Centre. The programme involved four teams: contact tracing, risk assessment, surveillance and outbreak investigation. Daily symptom surveillance was conducted over fourteen days for healthcare workers who were assessed to have low-, moderate- and high-risk of contracting COVID-19. A cross-sectional analysis was conducted for data collected over 24 weeks, from the 6th of March 2020 to the 20th of August 2020. RESULTS: A total of 1,174 healthcare workers were placed under surveillance. The majority were females (71.6%), aged between 25 and 34 years old (64.7%), were nursing staff (46.9%) and had no comorbidities (88.8%). A total of 70.9% were categorised as low-risk, 25.7% were moderate-risk, and 3.4% were at high risk of contracting COVID-19. One-third (35.2%) were symptomatic, with the sore throat (23.6%), cough (19.8%) and fever (5.0%) being the most commonly reported symptoms. A total of 17 healthcare workers tested positive for COVID-19, with a prevalence of 0.3% among all the healthcare workers. Risk category and presence of symptoms were associated with a positive COVID-19 test (p<0.001). Fever (p<0.001), cough (p = 0.003), shortness of breath (p = 0.015) and sore throat (p = 0.002) were associated with case positivity. CONCLUSION: COVID-19 symptom surveillance and risk-based assessment have merits to be included in a healthcare worker surveillance programme to safeguard the health of the workforce.


Assuntos
/métodos , Surtos de Doenças/prevenção & controle , Adulto , /tendências , Comorbidade , Busca de Comunicante/métodos , Estudos Transversais , Monitoramento Epidemiológico , Feminino , Pessoal de Saúde , Hospitais de Ensino , Humanos , Malásia/epidemiologia , Masculino , Pandemias , /isolamento & purificação
19.
PLoS One ; 16(4): e0250826, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33914810

RESUMO

We report on the results of a measurement study carried out on a commuter bus in Dublin, Ireland using the Google/Apple Exposure Notification (GAEN) API. This API is likely to be widely used by Covid-19 contact tracing apps. Measurements were collected between 60 pairs of Android handset locations and are publicly available. We find that the attenuation level reported by the GAEN API need not increase with distance between handsets, consistent with there being a complex radio environment inside a bus caused by the metal-rich environment. Changing the people sitting in a pair of seats can cause variations of ±10dB in the attenuation level reported by the GAEN API. Applying the rule used by the Swiss Covid-19 contact tracing app to trigger an exposure notification to our bus measurements we find that no exposure notifications would have been triggered despite the fact that all pairs of handsets were within 2m of one another for at least 15 mins. Applying an alternative threshold-based exposure notification rule can somewhat improve performance to a detection rate of 5% when an exposure duration threshold of 15 minutes is used, increasing to 8% when the exposure duration threshold is reduced to 10 mins. Stratifying the data by distance between pairs of handsets indicates that there is only a weak dependence of detection rate on distance.


Assuntos
Busca de Comunicante , Aplicativos Móveis , Transportes , /epidemiologia , Telefone Celular , Busca de Comunicante/métodos , Humanos , Irlanda/epidemiologia
20.
JAMA Netw Open ; 4(4): e218184, 2021 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-33929521

RESUMO

Importance: Digital contact tracing (DCT) apps have been released in several countries to help interrupt SARS-CoV-2 transmission chains. However, the effect of DCT on pandemic mitigation remains to be demonstrated. Objective: To estimate key populations and performance indicators along the exposure notification cascade of the SwissCovid DCT app in a clearly defined regional and temporal context. Design, Setting, and Participants: This comparative effectiveness study was based on a simulation informed by measured data from issued quarantine recommendations and positive SARS-CoV-2 test results after DCT exposure notifications in the canton of Zurich. A stochastic model was developed to re-create the DCT notification cascade for Zurich. Population sizes at each cascade step were estimated using triangulation based on publicly available administrative and observational research data for the study duration from September 1 to October 31, 2020. The resultant estimates were checked for internal consistency and consistency with upstream or downstream estimates in the cascade. Stochastic sampling from data-informed parameter distributions was performed to explore the robustness of results. Subsequently, key performance indicators were evaluated to assess the potential contribution of DCT compared with manual contact tracing. Main Outcomes and Measures: Receiving a voluntary quarantine recommendation and/or a positive SARS-CoV-2 test result after exposure notification. Results: In September 2020, 537 app users received a positive SARS-CoV-2 test result in Zurich, 324 of whom received and entered an upload authorization code. This code triggered an app notification for an estimated 1374 (95% simulation interval [SI], 932-2586) proximity contacts and led to 722 information hotline calls, with an estimated 170 callers (95% SI, 154-186) receiving a quarantine recommendation. An estimated 939 (95% SI, 720-1127) notified app users underwent testing for SARS-CoV-2, of whom 30 (95% SI, 23-36) had positive results after an app notification. Key indicator evaluations revealed that the DCT app triggered quarantine recommendations for the equivalent of 5% of all exposed contacts placed in quarantine by manual contact tracing. For every 10.9 (95% SI, 7.6-15.6) upload authorization codes entered in the app, 1 contact had positive test results for SARS-CoV-2 after app notification. Longitudinal indicator analyses demonstrated bottlenecks in the notification cascade, because capacity limits were reached owing to an increased incidence of SARS-CoV-2 infection in October 2020. Conclusions and Relevance: In this simulation study of the notification cascade of the SwissCovid DCT app, receipt of exposure notifications was associated with quarantine recommendations and identification of SARS-CoV-2-positive cases. These findings in notified proximity contacts reflect important intermediary steps toward transmission prevention.


Assuntos
Simulação por Computador , Busca de Comunicante , Notificação de Doenças , Transmissão de Doença Infecciosa , Aplicativos Móveis , Adulto , /epidemiologia , /transmissão , Controle de Doenças Transmissíveis/métodos , Controle de Doenças Transmissíveis/organização & administração , Busca de Comunicante/métodos , Busca de Comunicante/estatística & dados numéricos , Notificação de Doenças/métodos , Notificação de Doenças/estatística & dados numéricos , Transmissão de Doença Infecciosa/prevenção & controle , Transmissão de Doença Infecciosa/estatística & dados numéricos , Feminino , Humanos , Masculino , Quarentena , Suíça/epidemiologia
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