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1.
Biomedica ; 40(Supl. 2): 166-172, 2020 10 30.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-33152200

RESUMO

Introduction: The 2019 coronavirus pandemic (COVID-19) has caused around 25 million cases worldwide. Asymptomatic patients have been described as potential sources of transmission. However, there are difficulties to detect them and to establish their role in the dynamics of virus transmission, which hinders the implementation of prevention strategies. Objective: To describe the behavior of asymptomatic SARS-CoV-2 virus infection in a cohort of workers at the El Dorado "Luis Carlos Galán Sarmiento" International Airport in Bogotá, Colombia. Materials and methods: A prospective cohort of 212 workers from the El Dorado airport was designed. The follow-up began in June, 2020. A survey was used to characterize health and work conditions. Every 21 day, a nasopharyngeal swab was taken to identify the presence of SARS-CoV-2 using RT-PCR. We analyzed the behavior of the cycle threshold (ORF1ab and N genes) according to the day of follow-up. Results: In the first three follow-ups of the cohort, we found an incidence of SARS-CoV-2 infection of 16.51%. The proportion of positive contacts was 14.08%. The median threshold for cycle threshold was 33.53. Conclusion: We characterized the asymptomatic SARS-CoV-2 infection in a cohort of workers. The identification of asymptomatic infected persons continues to be a challenge for epidemiological surveillance systems.


Assuntos
Aeroportos , Infecções Assintomáticas , Betacoronavirus/isolamento & purificação , Técnicas de Laboratório Clínico , Infecções por Coronavirus/diagnóstico , Nasofaringe/virologia , Pandemias , Pneumonia Viral/diagnóstico , Adulto , Infecções Assintomáticas/epidemiologia , Betacoronavirus/genética , Betacoronavirus/fisiologia , Colômbia , Busca de Comunicante , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/virologia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Proteínas do Nucleocapsídeo/genética , Pneumonia Viral/epidemiologia , Pneumonia Viral/virologia , Estudos Prospectivos , RNA Viral/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Inquéritos e Questionários , Proteínas Virais/genética , Replicação Viral/genética , Local de Trabalho
2.
Sensors (Basel) ; 20(21)2020 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-33138115

RESUMO

During the COVID-19 pandemic, the temporary closure of physical activity and sports facilities, and the generalized cancellation or postponement of sports events have a massive impact on social and economic development. In this study, we explored the feasibility of using tracking data from a football match to assess interpersonal contact between individuals by calculating two measures of respiratory exposure. The dynamic tracking positioning of all players and referees during one international football match was analyzed. For each individual, two measures of respiratory exposure were calculated, based on the 2 m interpersonal distance recommendations for contact tracing for COVID-19 control. Overall, individuals spent a median of 0.12 mm:ss (IQR = 0.45 mm:ss) exposed to interpersonal contact of fewer than 2 m from others. The highest value of exposure was observed between two players of opposing teams (6.35 mm:ss). The results suggest that tracking data can be used to assess respiratory exposure to interpersonal contact in team sports, such as football. The measures of exposure calculated can be used to the prompt identification of high-risk contacts of COVID-19 cases during a match or a training session, but also the risk stratification of different sports and physical activities.


Assuntos
Busca de Comunicante/métodos , Infecções por Coronavirus/prevenção & controle , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Futebol , Betacoronavirus/isolamento & purificação , Infecções por Coronavirus/patologia , Infecções por Coronavirus/transmissão , Infecções por Coronavirus/virologia , Estudos Transversais , Humanos , Pneumonia Viral/patologia , Pneumonia Viral/transmissão , Pneumonia Viral/virologia , Gravação em Vídeo
3.
J R Soc Interface ; 17(172): 20200393, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33143594

RESUMO

The basic reproductive number, R0, is one of the most common and most commonly misapplied numbers in public health. Often used to compare outbreaks and forecast pandemic risk, this single number belies the complexity that different epidemics can exhibit, even when they have the same R0. Here, we reformulate and extend a classic result from random network theory to forecast the size of an epidemic using estimates of the distribution of secondary infections, leveraging both its average R0 and the underlying heterogeneity. Importantly, epidemics with lower R0 can be larger if they spread more homogeneously (and are therefore more robust to stochastic fluctuations). We illustrate the potential of this approach using different real epidemics with known estimates for R0, heterogeneity and epidemic size in the absence of significant intervention. Further, we discuss the different ways in which this framework can be implemented in the data-scarce reality of emerging pathogens. Lastly, we demonstrate that without data on the heterogeneity in secondary infections for emerging infectious diseases like COVID-19 the uncertainty in outbreak size ranges dramatically. Taken together, our work highlights the critical need for contact tracing during emerging infectious disease outbreaks and the need to look beyond R0.


Assuntos
Betacoronavirus , Coinfecção/complicações , Doenças Transmissíveis Emergentes/epidemiologia , Infecções por Coronavirus/complicações , Infecções por Coronavirus/epidemiologia , Modelos Biológicos , Pneumonia Viral/complicações , Pneumonia Viral/epidemiologia , Busca de Comunicante , Infecções por Coronavirus/transmissão , Humanos , Pandemias , Pneumonia Viral/transmissão , Fatores de Risco
5.
MMWR Morb Mortal Wkly Rep ; 69(44): 1625-1630, 2020 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-33151915

RESUMO

Correctional and detention facilities have been disproportionately affected by coronavirus disease 2019 (COVID-19) because of shared space and movement of staff members and detained persons within facilities (1,2). During March 1-April 30, 2020, at Cook County Jail in Chicago, Illinois, >900 COVID-19 cases were diagnosed across all 10 housing divisions, representing 13 unique buildings.† Movement within the jail was examined through network analyses and visualization, a field that examines elements within a network and the connections between them. This methodology has been used to supplement contact tracing investigations for tuberculosis and to understand how social networks contribute to transmission of sexually transmitted infections (3-5). Movements and connections of 5,884 persons (3,843 [65%] detained persons and 2,041 [35%] staff members) at the jail during March 1-April 30 were analyzed. A total of 472 (12.3%) COVID-19 cases were identified among detained persons and 198 (9.7%) among staff members. Among 103,701 shared-shift connections among staff members, 1.4% occurred between persons with COVID-19, a percentage that is significantly higher than the expected 0.9% by random occurrence alone (p<0.001), suggesting that additional transmission occurred within this group. The observed connections among detained persons with COVID-19 were significantly lower than expected (1.0% versus 1.1%, p<0.001) when considering only the housing units in which initial transmission occurred, suggesting that the systematic isolation of persons with COVID-19 is effective at limiting transmission. A network-informed approach can identify likely points of high transmission, allowing for interventions to reduce transmission targeted at these groups or locations, such as by reducing convening of staff members, closing breakrooms, and cessation of contact sports.


Assuntos
Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/transmissão , Surtos de Doenças , Pneumonia Viral/epidemiologia , Pneumonia Viral/transmissão , Prisões , Busca de Comunicante , Visualização de Dados , Humanos , Illinois/epidemiologia , Pandemias , Rede Social
6.
MMWR Morb Mortal Wkly Rep ; 69(44): 1654-1659, 2020 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-33151922

RESUMO

On June 3, 2020, a woman aged 73 years (patient A) with symptoms consistent with coronavirus disease 2019 (COVID-19) (1) was evaluated at the emergency department of the Hopi Health Care Center (HHCC, an Indian Health Services facility) and received a positive test result for SARS-CoV-2, the virus that causes COVID-19. The patient's symptoms commenced on May 27, and a sibling (patient B) of the patient experienced symptom onset the following day. On May 23, both patients had driven together and spent time in a retail store in Flagstaff, Arizona. Because of their similar exposures, symptom onset dates, and overlapping close contacts, these patients are referred to as co-index patients. The co-index patients had a total of 58 primary (i.e., direct) and secondary contacts (i.e., contacts of a primary contact); among these, 27 (47%) received positive SARS-CoV-2 test results. Four (15%) of the 27 contacts who became ill were household members of co-index patient B, 14 (52%) had attended family gatherings, one was a child who might have transmitted SARS-CoV-2 to six contacts, and eight (30%) were community members. Findings from the outbreak investigation prompted the HHCC and Hopi Tribe leadership to strengthen community education through community health representatives, public health nurses, and radio campaigns. In communities with similar extended family interaction, emphasizing safe ways to stay in touch, along with wearing a mask, frequent hand washing, and physical distancing might help limit the spread of disease.


Assuntos
Infecções por Coronavirus/etnologia , Infecções por Coronavirus/prevenção & controle , Surtos de Doenças , Índios Norte-Americanos/estatística & dados numéricos , Pandemias/prevenção & controle , Pneumonia Viral/etnologia , Pneumonia Viral/prevenção & controle , Adolescente , Adulto , Idoso , Arizona/epidemiologia , Betacoronavirus/isolamento & purificação , Criança , Pré-Escolar , Técnicas de Laboratório Clínico , Busca de Comunicante , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/transmissão , Feminino , Humanos , Lactente , Laboratórios , Masculino , Pessoa de Meia-Idade , Pneumonia Viral/transmissão , Adulto Jovem
7.
MMWR Morb Mortal Wkly Rep ; 69(45): 1686-1690, 2020 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-33180752

RESUMO

Large indoor gatherings pose a high risk for transmission of SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19), and have the potential to be super-spreading events (1,2). Such events are associated with explosive growth, followed by sustained transmission (3). During August 7-September 14, 2020, the Maine Center for Disease Control and Prevention (MeCDC) investigated a COVID-19 outbreak linked to a wedding reception attended by 55 persons in a rural Maine town. In addition to the community outbreak, secondary and tertiary transmission led to outbreaks at a long-term care facility 100 miles away and at a correctional facility approximately 200 miles away. Overall, 177 COVID-19 cases were epidemiologically linked to the event, including seven hospitalizations and seven deaths (four in hospitalized persons). Investigation revealed noncompliance with CDC's recommended mitigation measures. To reduce transmission, persons should avoid large gatherings, practice physical distancing, wear masks, stay home when ill, and self-quarantine after exposure to a person with confirmed SARS-CoV-2 infection. Persons can work with local health officials to increase COVID-19 awareness and determine the best policies for organizing social events to prevent outbreaks in their communities.


Assuntos
Infecções por Coronavirus/epidemiologia , Surtos de Doenças , Pneumonia Viral/epidemiologia , Prisões/estatística & dados numéricos , Instituições Residenciais/estatística & dados numéricos , População Rural/estatística & dados numéricos , Adolescente , Adulto , Idoso , Betacoronavirus/isolamento & purificação , Técnicas de Laboratório Clínico , Busca de Comunicante , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/transmissão , Feminino , Humanos , Maine/epidemiologia , Masculino , Casamento , Pessoa de Meia-Idade , Pandemias , Pneumonia Viral/transmissão , Adulto Jovem
8.
MMWR Morb Mortal Wkly Rep ; 69(45): 1691-1694, 2020 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-33180757

RESUMO

Mitigation measures, including stay-at-home orders and public mask wearing, together with routine public health interventions such as case investigation with contact tracing and immediate self-quarantine after exposure, are recommended to prevent and control the transmission of SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19) (1-3). On March 11, the first COVID-19 case in Delaware was reported to the Delaware Division of Public Health (DPH). The state responded to ongoing community transmission with investigation of all identified cases (commencing March 11), issuance of statewide stay-at-home orders (March 24-June 1), a statewide public mask mandate (from April 28), and contact tracing (starting May 12). The relationship among implementation of mitigation strategies, case investigations, and contact tracing and COVID-19 incidence and associated hospitalization and mortality was examined during March-June 2020. Incidence declined by 82%, hospitalization by 88%, and mortality by 100% from late April to June 2020, as the mask mandate and contact tracing were added to case investigations and the stay-at-home order. Among 9,762 laboratory-confirmed COVID-19 cases reported during March 11-June 25, 2020, two thirds (6,527; 67%) of patients were interviewed, and 5,823 (60%) reported completing isolation. Among 2,834 contacts reported, 882 (31%) were interviewed and among these contacts, 721 (82%) reported completing quarantine. Implementation of mitigation measures, including mandated mask use coupled with public health interventions, was followed by reductions in COVID-19 incidence and associated hospitalizations and mortality. The combination of state-mandated community mitigation efforts and routine public health interventions can reduce the occurrence of new COVID-19 cases, hospitalizations, and deaths.


Assuntos
Infecções por Coronavirus/prevenção & controle , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Saúde Pública/legislação & jurisprudência , Adolescente , Adulto , Idoso , Busca de Comunicante , Infecções por Coronavirus/mortalidade , Infecções por Coronavirus/terapia , Infecções por Coronavirus/transmissão , Delaware/epidemiologia , Feminino , Hospitalização/estatística & dados numéricos , Humanos , Masculino , Máscaras/estatística & dados numéricos , Pessoa de Meia-Idade , Pneumonia Viral/mortalidade , Pneumonia Viral/terapia , Pneumonia Viral/transmissão , Quarentena/legislação & jurisprudência , Adulto Jovem
10.
BMC Public Health ; 20(1): 1713, 2020 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-33198707

RESUMO

BACKGROUND: Mathematical modeling studies have suggested that pre-emptive school closures alone have little overall impact on SARS-CoV-2 transmission, but reopening schools in the background of community contact reduction presents a unique scenario that has not been fully assessed. METHODS: We adapted a previously published model using contact information from Shanghai to model school reopening under various conditions. We investigated different strategies by combining the contact patterns observed between different age groups during both baseline and "lockdown" periods. We also tested the robustness of our strategy to the assumption of lower susceptibility to infection in children under age 15 years. RESULTS: We find that reopening schools for all children would maintain a post-intervention R0 < 1 up to a baseline R0 of approximately 3.3 provided that daily contacts among children 10-19 years are reduced to 33% of baseline. This finding was robust to various estimates of susceptibility to infection in children relative to adults (up to 50%) and to estimates of various levels of concomitant reopening in the rest of the community (up to 40%). However, full school reopening without any degree of contact reduction in the school setting returned R0 virtually back to baseline, highlighting the importance of mitigation measures. CONCLUSIONS: These results, based on contact structure data from Shanghai, suggest that schools can reopen with proper precautions during conditions of extreme contact reduction and during conditions of reasonable levels of reopening in the rest of the community.


Assuntos
Infecções por Coronavirus/transmissão , Pneumonia Viral/transmissão , Instituições Acadêmicas/organização & administração , Criança , China/epidemiologia , Busca de Comunicante , Infecções por Coronavirus/epidemiologia , Humanos , Modelos Teóricos , Pandemias , Pneumonia Viral/epidemiologia
11.
Science ; 370(6517): 691-697, 2020 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-33154136

RESUMO

Although most cases of coronavirus disease 2019 (COVID-19) have occurred in low-resource countries, little is known about the epidemiology of the disease in such contexts. Data from the Indian states of Tamil Nadu and Andhra Pradesh provide a detailed view into severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission pathways and mortality in a high-incidence setting. Reported cases and deaths have been concentrated in younger cohorts than would be expected from observations in higher-income countries, even after accounting for demographic differences across settings. Among 575,071 individuals exposed to 84,965 confirmed cases, infection probabilities ranged from 4.7 to 10.7% for low-risk and high-risk contact types, respectively. Same-age contacts were associated with the greatest infection risk. Case fatality ratios spanned 0.05% at ages of 5 to 17 years to 16.6% at ages of 85 years or more. Primary data from low-resource countries are urgently needed to guide control measures.


Assuntos
Infecções por Coronavirus/mortalidade , Infecções por Coronavirus/transmissão , Pneumonia Viral/mortalidade , Pneumonia Viral/transmissão , Adolescente , Adulto , Distribuição por Idade , Idoso , Idoso de 80 Anos ou mais , Betacoronavirus , Criança , Pré-Escolar , Busca de Comunicante , Feminino , Humanos , Incidência , Índia/epidemiologia , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Pandemias , Adulto Jovem
13.
BMC Infect Dis ; 20(1): 760, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-33059620

RESUMO

BACKGROUND: A more stringent QuantiFERON-TB Gold In-Tube (QFT) conversion (from negative to positive) definition has been proposed to allow more definite detection of recent tuberculosis (TB) infection. We explored alternative conversion definitions to assist the interpretation of serial QFT results and estimate incidence of TB infection in a large cohort study. METHODS: We used QFT serial results from TB household contacts aged ≥15 years, collected at baseline and during two follow-up visits (2006-2011) as part of a cohort study in 24 communities in Zambia and South Africa (SA). Conversion rates using the manufacturers' definition (interferon-gamma (IFN-g) < 0.35 to ≥0.35, 'def1') were compared with stricter definitions (IFN-g < 0.2 to ≥0.7 IU/ml, 'def2'; IFN-g < 0.2 to ≥1.05 IU/ml, 'def3'; IFN-g < 0.2 to ≥1.4 IU/ml, 'def4'). Poisson regression was used for analysis. RESULTS: One thousand three hundred sixty-five individuals in Zambia and 822 in SA had QFT results available. Among HIV-negative individuals, the QFT conversion rate was 27.4 per 100 person-years (CI:22.9-32.6) using def1, 19.0 using def2 (CI:15.2-23.7), 14.7 using def3 (CI:11.5-18.8), and 12.0 using def4 (CI:9.2-15.7). Relative differences across def1-def4 were similar in Zambia and SA. Using def1, conversion was less likely if HIV positive not on antiretroviral treatment compared to HIV negative (aRR = 0.7, 95%CI = 0.4-0.9), in analysis including both countries. The same direction of associations were found using def 2-4. CONCLUSION: High conversion rates were found even with the strictest definition, indicating high incidence of TB infection among household contacts of TB patients in these communities. The trade-off between sensitivity and specificity using different thresholds of QFT conversion remains unknown due to the absence of a reference standard. However, we identified boundaries within which an appropriate definition might fall, and our strictest definition plausibly has high specificity.


Assuntos
Testes de Liberação de Interferon-gama/métodos , Tuberculose/diagnóstico , Antirretrovirais/uso terapêutico , Estudos de Coortes , Busca de Comunicante , Características da Família , Soropositividade para HIV , Humanos , Incidência , Prevalência , África do Sul/epidemiologia , Tuberculose/epidemiologia , Zâmbia/epidemiologia
14.
Artigo em Inglês | MEDLINE | ID: mdl-33113936

RESUMO

The novel coronavirus Severe Acute Respiratory Syndrome (SARS)-Coronavirus-2 (CoV-2) has resulted in an ongoing pandemic and has affected over 200 countries around the world. Mathematical epidemic models can be used to predict the course of an epidemic and develop methods for controlling it. As social contact is a key factor in disease spreading, modeling epidemics on contact networks has been increasingly used. In this work, we propose a simulation model for the spread of Coronavirus Disease 2019 (COVID-19) in Saudi Arabia using a network-based epidemic model. We generated a contact network that captures realistic social behaviors and dynamics of individuals in Saudi Arabia. The proposed model was used to evaluate the effectiveness of the control measures employed by the Saudi government, to predict the future dynamics of the disease in Saudi Arabia according to different scenarios, and to investigate multiple vaccination strategies. Our results suggest that Saudi Arabia would have faced a nationwide peak of the outbreak on 21 April 2020 with a total of approximately 26 million infections had it not imposed strict control measures. The results also indicate that social distancing plays a crucial role in determining the future local dynamics of the epidemic. Our results also show that the closure of schools and mosques had the maximum impact on delaying the epidemic peak and slowing down the infection rate. If a vaccine does not become available and no social distancing is practiced from 10 June 2020, our predictions suggest that the epidemic will end in Saudi Arabia at the beginning of November with over 13 million infected individuals, and it may take only 15 days to end the epidemic after 70% of the population receive a vaccine.


Assuntos
Infecções por Coronavirus , Coronavirus , Modelos Teóricos , Pandemias , Pneumonia Viral , Betacoronavirus , Busca de Comunicante , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/transmissão , Humanos , Pneumonia Viral/epidemiologia , Pneumonia Viral/transmissão , Arábia Saudita/epidemiologia
15.
J Glob Health ; 10(2): 020103, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33110502

RESUMO

The COVID-19 pandemic has put health systems, economies and societies under unprecedented strain, calling for innovative approaches. Scotland's government, like those elsewhere, is facing difficult decisions about how to deploy digital technologies and data to help contain, control and manage the disease, while also respecting citizens' rights. This paper explores the ethical challenges presented by these methods, with particular emphasis on mobile apps associated with contact tracing. Drawing on UK and international experiences, it examines issues such as public trust, data privacy and technology design; how changing disease threats and contextual factors can affect the balance between public benefits and risks; and the importance of transparency, accountability and stakeholder participation for the trustworthiness and good-governance of digital systems and strategies. Analysis of recent technology debates, controversial programmes and emerging outcomes in comparable countries implementing contact tracing apps, reveals sociotechnical complexities and unexpected paradoxes that warrant further study and underlines the need for holistic, inclusive and adaptive strategies. The paper also considers the potential role of these apps as Scotland transitions to the 'new normal', outlines challenges and opportunities for public engagement, and poses a set of ethical questions to inform decision-making at multiple levels, from software design to institutional governance.


Assuntos
Busca de Comunicante/ética , Transmissão de Doença Infecciosa/ética , Direitos Humanos/ética , Aplicativos Móveis/ética , Pandemias/ética , Betacoronavirus , Busca de Comunicante/métodos , Infecções por Coronavirus/prevenção & controle , Transmissão de Doença Infecciosa/prevenção & controle , Governo , Humanos , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Escócia/epidemiologia , Participação dos Interessados , Tecnologia/ética
16.
JMIR Mhealth Uhealth ; 8(10): e23148, 2020 10 29.
Artigo em Inglês | MEDLINE | ID: mdl-33006944

RESUMO

BACKGROUND: Effective contact tracing is labor intensive and time sensitive during the COVID-19 pandemic, but also essential in the absence of effective treatment and vaccines. Singapore launched the first Bluetooth-based contact tracing app-TraceTogether-in March 2020 to augment Singapore's contact tracing capabilities. OBJECTIVE: This study aims to compare the performance of the contact tracing app-TraceTogether-with that of a wearable tag-based real-time locating system (RTLS) and to validate them against the electronic medical records at the National Centre for Infectious Diseases (NCID), the national referral center for COVID-19 screening. METHODS: All patients and physicians in the NCID screening center were issued RTLS tags (CADI Scientific) for contact tracing. In total, 18 physicians were deployed to the NCID screening center from May 10 to May 20, 2020. The physicians activated the TraceTogether app (version 1.6; GovTech) on their smartphones during shifts and urged their patients to use the app. We compared patient contacts identified by TraceTogether and those identified by RTLS tags within the NCID vicinity during physicians' 10-day posting. We also validated both digital contact tracing tools by verifying the physician-patient contacts with the electronic medical records of 156 patients who attended the NCID screening center over a 24-hour time frame within the study period. RESULTS: RTLS tags had a high sensitivity of 95.3% for detecting patient contacts identified either by the system or TraceTogether while TraceTogether had an overall sensitivity of 6.5% and performed significantly better on Android phones than iPhones (Android: 9.7%, iPhone: 2.7%; P<.001). When validated against the electronic medical records, RTLS tags had a sensitivity of 96.9% and specificity of 83.1%, while TraceTogether only detected 2 patient contacts with physicians who did not attend to them. CONCLUSIONS: TraceTogether had a much lower sensitivity than RTLS tags for identifying patient contacts in a clinical setting. Although the tag-based RTLS performed well for contact tracing in a clinical setting, its implementation in the community would be more challenging than TraceTogether. Given the uncertainty of the adoption and capabilities of contact tracing apps, policy makers should be cautioned against overreliance on such apps for contact tracing. Nonetheless, leveraging technology to augment conventional manual contact tracing is a necessary move for returning some normalcy to life during the long haul of the COVID-19 pandemic.


Assuntos
Sistemas Computacionais , Busca de Comunicante/instrumentação , Infecções por Coronavirus/prevenção & controle , Aplicativos Móveis , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Dispositivos Eletrônicos Vestíveis , Técnicas de Laboratório Clínico , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/epidemiologia , Estudos Transversais , Registros Eletrônicos de Saúde , Humanos , Relações Médico-Paciente , Pneumonia Viral/epidemiologia , Reprodutibilidade dos Testes , Singapura/epidemiologia
17.
N Z Med J ; 133(1524): 28-39, 2020 10 30.
Artigo em Inglês | MEDLINE | ID: mdl-33119568

RESUMO

AIMS: We aimed to determine the effectiveness of surveillance using testing for SARS-CoV-2 to identify an outbreak arising from a single case of border control failure in a country that has eliminated community transmission of COVID-19: New Zealand. METHODS: A stochastic version of the SEIR model CovidSIM v1.1 designed specifically for COVID-19 was utilised. It was seeded with New Zealand population data and relevant parameters sourced from the New Zealand and international literature. RESULTS: For what we regard as the most plausible scenario with an effective reproduction number of 2.0, the results suggest that 95% of outbreaks from a single imported case would be detected in the period up to day 36 after introduction. At the time point of detection, there would be a median number of five infected cases in the community (95% range: 1-29). To achieve this level of detection, an ongoing programme of 5,580 tests per day (1,120 tests per million people per day) for the New Zealand population would be required. The vast majority of this testing (96%) would be of symptomatic cases in primary care settings and the rest in hospitals. CONCLUSIONS: This model-based analysis suggests that a surveillance system with a very high level of routine testing is probably required to detect an emerging or re-emerging SARS-CoV-2 outbreak within five weeks of a border control failure in a nation that had previously eliminated COVID-19. Nevertheless, there are plausible strategies to enhance testing yield and cost-effectiveness and potential supplementary surveillance systems such as the testing of town/city sewerage systems for the pandemic virus.


Assuntos
Simulação por Computador , Infecções por Coronavirus/epidemiologia , Monitoramento Epidemiológico , Pneumonia Viral/epidemiologia , Betacoronavirus , Busca de Comunicante , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/transmissão , Hospitais , Humanos , Nova Zelândia/epidemiologia , Pandemias , Pneumonia Viral/diagnóstico , Pneumonia Viral/transmissão , Atenção Primária à Saúde , Quarentena
18.
Phys Biol ; 17(6): 065007, 2020 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-33048841

RESUMO

We argue that frequent sampling of the fraction of a priori non-symptomatic but infectious humans (either by random or cohort testing) significantly improves the management of the COVID-19 pandemic, when compared to intervention strategies relying on data from symptomatic cases only. This is because such sampling measures the incidence of the disease, the key variable controlled by restrictive measures, and thus anticipates the load on the healthcare system due to progression of the disease. The frequent testing of non-symptomatic infectiousness will (i) significantly improve the predictability of the pandemic, (ii) allow informed and optimized decisions on how to modify restrictive measures, with shorter delay times than the present ones, and (iii) enable the real-time assessment of the efficiency of new means to reduce transmission rates. These advantages are quantified by considering a feedback and control model of mitigation where the feedback is derived from the evolution of the daily measured prevalence. While the basic model we propose aggregates data for the entire population of a country such as Switzerland, we point out generalizations which account for hot spots which are analogous to Anderson-localized regions in the theory of diffusion in random media.


Assuntos
Betacoronavirus/isolamento & purificação , Técnicas de Laboratório Clínico , Busca de Comunicante , Infecções por Coronavirus/epidemiologia , Modelos Teóricos , Pandemias , Pneumonia Viral/epidemiologia , Doenças Assintomáticas , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/prevenção & controle , Infecções por Coronavirus/transmissão , Retroalimentação , Humanos , Pandemias/prevenção & controle , Pneumonia Viral/diagnóstico , Pneumonia Viral/prevenção & controle , Pneumonia Viral/transmissão
19.
Phys Biol ; 17(6): 065010, 2020 10 21.
Artigo em Inglês | MEDLINE | ID: mdl-33085650

RESUMO

Shelter-in-place and other confinement strategies implemented in the current COVID-19 pandemic have created stratified patterns of contacts between people: close contacts within households and more distant contacts between the households. The epidemic transmission dynamics is significantly modified as a consequence. We introduce a minimal model that incorporates these household effects in the framework of mean-field theory and numerical simulations. We show that the reproduction number R 0 depends on the household size in a surprising way: linearly for relatively small households, and as a square root of size for larger households. We discuss the implications of the findings for the lockdown, test, tracing, and isolation policies.


Assuntos
Betacoronavirus/fisiologia , Busca de Comunicante , Infecções por Coronavirus/epidemiologia , Modelos Teóricos , Pandemias , Pneumonia Viral/epidemiologia , Simulação por Computador , Infecções por Coronavirus/transmissão , Características da Família , Humanos , Pneumonia Viral/transmissão
20.
Sci Rep ; 10(1): 18543, 2020 10 29.
Artigo em Inglês | MEDLINE | ID: mdl-33122753

RESUMO

The international community has been put in an unprecedented situation by the COVID-19 pandemic. Creating models to describe and quantify alternative mitigation strategies becomes increasingly urgent. In this study, we propose an agent-based model of disease transmission in a society divided into closely connected families, workplaces, and social groups. This allows us to discuss mitigation strategies, including targeted quarantine measures. We find that workplace and more diffuse social contacts are roughly equally important to disease spread, and that an effective lockdown must target both. We examine the cost-benefit of replacing a lockdown with tracing and quarantining contacts of the infected. Quarantine can contribute substantially to mitigation, even if it has short duration and is done within households. When reopening society, testing and quarantining is a strategy that is much cheaper in terms of lost workdays than a long lockdown. A targeted quarantine strategy is quite efficient with only 5 days of quarantine, and its effect increases when testing is more widespread.


Assuntos
Técnicas de Laboratório Clínico/economia , Infecções por Coronavirus/economia , Análise Custo-Benefício , Pandemias/economia , Pneumonia Viral/economia , Quarentena/economia , Busca de Comunicante/economia , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/prevenção & controle , Humanos , Pandemias/prevenção & controle , Pneumonia Viral/diagnóstico , Pneumonia Viral/epidemiologia , Pneumonia Viral/prevenção & controle
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