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Open accessJournal ArticleDOI: 10.1371/JOURNAL.PONE.0246987

Impact of contact tracing on COVID-19 mortality: An impact evaluation using surveillance data from Colombia.

04 Mar 2021-PLOS ONE (Public Library of Science (PLoS))-Vol. 16, Iss: 3
Abstract: BACKGROUND: Contact tracing is a crucial part of the public health surveillance toolkit. However, it is labor-intensive and costly to carry it out. Some countries have faced challenges implementing contact tracing, and no impact evaluations using empirical data have assessed its impact on COVID-19 mortality. This study assesses the impact of contact tracing in a middle-income country, providing data to support the expansion and optimization of contact tracing strategies to improve infection control. METHODS: We obtained publicly available data on all confirmed COVID-19 cases in Colombia between March 2 and June 16, 2020. (N = 54,931 cases over 135 days of observation). As suggested by WHO guidelines, we proxied contact tracing performance as the proportion of cases identified through contact tracing out of all cases identified. We calculated the daily proportion of cases identified through contact tracing across 37 geographical units (32 departments and five districts). Further, we used a sequential log-log fixed-effects model to estimate the 21-days, 28-days, 42-days, and 56-days lagged impact of the proportion of cases identified through contact tracing on daily COVID-19 mortality. Both the proportion of cases identified through contact tracing and the daily number of COVID-19 deaths are smoothed using 7-day moving averages. Models control for the prevalence of active cases, second-degree polynomials, and mobility indices. Robustness checks to include supply-side variables were performed. RESULTS: We found that a 10 percent increase in the proportion of cases identified through contact tracing is related to COVID-19 mortality reductions between 0.8% and 3.4%. Our models explain between 47%-70% of the variance in mortality. Results are robust to changes of specification and inclusion of supply-side variables. CONCLUSION: Contact tracing is instrumental in containing infectious diseases. Its prioritization as a surveillance strategy will substantially impact reducing deaths while minimizing the impact on the fragile economic systems of lower and middle-income countries. This study provides lessons for other LMIC.

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Topics: Contact tracing (63%)
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9 results found


Open accessJournal ArticleDOI: 10.1016/J.ECLINM.2021.100801
30 Mar 2021-EClinicalMedicine
Abstract: Background Worldwide, Peru has one of the highest infection fatality rates of COVID-19, and its capital city, Lima, accumulates roughly 50% of diagnosed cases Despite surveillance efforts to assess the extent of the pandemic, reported cases and deaths only capture a fraction of its impact due to COVID-19's broad clinical spectrum This study aimed to estimate the seroprevalence of SARS-CoV-2 in Lima, stratified by age, sex, region, socioeconomic status (SES), overcrowding, and symptoms Methods We conducted a multi-stage, population-based serosurvey in Lima, between June 28th and July 9th, 2020, after 115 days of the index case and after the first peak cases We collected whole blood samples by finger-prick and applied a structured questionnaire A point-of-care rapid serological test assessed IgM and IgG antibodies against SARS-CoV-2 Seroprevalence estimates were adjusted by sampling weights and test performance Additionally, we performed RT-PCR molecular assays to seronegatives and estimated the infection prevalence Findings We enrolled 3212 participants from 797 households and 241 sample clusters from Lima in the analysis The SARS-CoV-2 seroprevalence was 20·8% (95%CI 17·2-23·5), and the prevalence was 25·2% (95%CI 22·5-28·2) Seroprevalence was equally distributed by sex (aPR=0·96 [95%CI 0·85-1·09, p = 0·547]) and across all age groups, including ≥60 versus ≤11 years old (aPR=0·96 [95%CI 0·73-1·27, p = 0·783]) A gradual decrease in SES was associated with higher seroprevalence (aPR=3·41 [95%CI 1·90-6·12, p<0·001] in low SES) Also, a gradual increase in the overcrowding index was associated with higher seroprevalence (aPR=1·99 [95%CI 1·41-2·81, p<0·001] in the fourth quartile) Seroprevalence was also associated with contact with a suspected or confirmed COVID-19 case, whether a household member (48·9%, aPR=2·67 [95%CI 2·06-3·47, p<0·001]), other family members (27·3%, aPR=1·66 [95%CI 1·15-2·40, p = 0·008]) or a workmate (34·1%, aPR=2·26 [95%CI 1·53-3·35, p<0·001]) More than half of seropositive participants reported never having had symptoms (56·1%, 95% CI 49·7-62·3) Interpretation This first estimate of SARS-CoV-2 seroprevalence in Lima shows an intense transmission scenario, despite the government's numerous interventions early established Susceptibles across age groups show that physical distancing interventions must not be relaxed SES and overcrowding households are associated with seroprevalence This study highlights the importance of considering the existing social inequalities for implementing the response to control transmission in low- and middle-income countries

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Topics: Seroprevalence (58%), Population (52%), Overcrowding (50%)

15 Citations


Open accessPosted ContentDOI: 10.1101/2021.04.08.21254922
11 Apr 2021-medRxiv
Abstract: BackgroundIn the context of the COVID-19 pandemic, public health teams have struggled to conduct monitoring for confirmed or suspicious COVID-19 patients. However, monitoring these patients is critical to improving the chances of survival, and therefore, a prioritization strategy for these patients is warranted. This study developed a monitoring algorithm for COVID-19 patients for the Colombian Ministry of Health and Social Protection (MOH). MethodsThis work included 1) a literature review, 2) consultations with MOH and National Institute of Health officials, and 3) data analysis of all positive COVID-19 cases and their outcomes. We used clinical and socioeconomic variables to develop a set of risk categories to identify severe cases of COVID-19. ResultsThis tool provided four different risk categories for COVID-19 patients. As soon as the time of diagnosis, this tool can identify 91% of all severe and fatal COVID-19 cases within the first two risk categories. ConclusionThis tool is a low-cost strategy to prioritize patients at higher risk of experiencing severe COVID-19. This tool was developed so public health teams can focus their scarce monitoring resources on individuals at higher mortality risk. This tool can be easily adapted to the context of other lower and middle-income countries. Policymakers would benefit from this low-cost strategy to reduce COVID-19 mortality, particularly during outbreaks.

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Topics: Public health (54%)

1 Citations


Open accessPosted Content
Michela Meister1, Jon Kleinberg1Institutions (1)
Abstract: Contact tracing is a key tool for managing epidemic diseases like HIV, tuberculosis, and COVID-19. Manual investigations by human contact tracers remain a dominant way in which this is carried out. This process is limited by the number of contact tracers available, who are often overburdened during an outbreak or epidemic. As a result, a crucial decision in any contact tracing strategy is, given a set of contacts, which person should a tracer trace next? In this work, we develop a formal model that articulates these questions and provides a framework for comparing contact tracing strategies. Through analyzing our model, we give provably optimal prioritization policies via a clean connection to a tool from operations research called a "branching bandit". Examining these policies gives qualitative insight into trade-offs in contact tracing applications.

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Topics: Contact tracing (54%)

Open accessPosted ContentDOI: 10.1101/2021.09.10.21263410
14 Sep 2021-medRxiv
Abstract: Importance A steady increase in acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cases worldwide is causing some regions of the world to withstand a third or even fourth wave of contagion. Swift detection of SARS-CoV-2 infection is paramount for the containment of cases, prevention of sustained contagion; and most importantly, for the reduction of mortality. Objective To evaluate the performance and validity of the COVISTIX™ rapid antigen test, for the detection of SARS-CoV-2 in an unselected population and compare it to Panbio™ rapid antigen test and RT-PCR. Design This is comparative effectiveness study; samples were collected at two point-of-care facilities in Mexico City between May and August 2021. Participants Recruited individuals were probable COVID-19 cases, either symptomatic or asymptomatic persons that were at risk of infection due to close contact to SARS-CoV-2 positive cases. Diagnostic intervention RT-PCR was used as gold standard for detection of SARS-CoV-2 in nasal and nasopharyngeal swabs, study subjects were tested in parallel either with the COVISTIX™ or with Panbio™ rapid antigen test. Main outcome Diagnostic performance of the COVISTIX™ assay is adequate in all commers since its accuracy parameters were not affected in samples collected after 7 days of symptom onset, and it detected almost 65% of samples with a Ct-value between 30 and 34. Results For the population tested with COVISTIX™ (n=783), specificity and sensitivity of the was 96.0% (CI95% 94.0-98.0) and 81% (CI95% 76.0-85.0), as for the Panbio™ (n=2202) population, was 99.0% (CI95%: 0.99-1.00) and 62% (CI%: 58.0-64.0%), respectively. Conclusions and relevance The COVISTIX™ rapid antigen test shows a high performance in all comers, thus, this test is also adequate for testing patients who have passed the peak of viral shedding or for asymptomatic patients.

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Topics: Rapid antigen test (60%), Population (55%), Gold standard (test) (51%)

Open accessPosted ContentDOI: 10.1101/2021.06.16.21258989
18 Jun 2021-medRxiv
Abstract: Background. Since April 28, 2021, in Colombia there are social protests with numerous demonstrations in various cities. This occurs whereas the country faces the third wave of the COVID-19 pandemic. The aim of this study was to assess the effect of social protests on the number and trend of the confirmed COVID-19 cases in some selected Colombian cities where social protests had more intensity. Methods. We performed and interrupted time-series analysis (ITSA) and Autoregressive Integrated Moving Average (ARIMA) models, based on the confirmed COVID-19 cases in Colombia, between March 1 and May 15, 2021, for the cities of Bogota, Cali, Barranquilla, Medellin, and Bucaramanga. The ITSA models estimated the impact of social demonstrations on the number and trend of cases for each city by using Newey-West standard errors and ARIMA models assessed the overall pattern of the series and effect of the intervention. We considered May 2, 2021, as the intervention date for the analysis, five days after social demonstrations started in the country. Findings. During the study period the number of cases by city was 1,014,815 for Bogota, 192,320 for Cali, 175,269 for Barranquilla, 311,904 for Medellin, and 62,512 for Bucaramanga. Heterogeneous results were found among cities. Only for the cities of Cali and Barranquilla statistically significant changes in trend of the number of cases were obtained after the intervention: positive in the first city, negative in the second one. None ARIMA models show evidence of abrupt changes in the trend of the series for any city and intervention effect was only positive for Bucaramanga. Interpretation. The findings confer solid evidence that social protests had an heterogenous effect on the number and trend of COVID-19 cases. Divergent effects might be related to the epidemiologic time of the pandemic and the characteristics of the social protests. Assessing the effect of social protests within a pandemic is complex and there are several methodological limitations. Further analyses are required with longer time-series data.

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23 results found


Open accessJournal ArticleDOI: 10.1016/S1473-3099(20)30120-1
Ensheng Dong1, Hongru Du1, Lauren Gardner1Institutions (1)
Abstract: The outbreak of the 2019 novel coronavirus disease (COVID-19) has induced a considerable degree of fear, emotional stress and anxiety among individuals around t

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Topics: Dashboard (business) (62%), Web application (53%)

5,397 Citations


Open accessJournal ArticleDOI: 10.1126/SCIENCE.ABB6936
Luca Ferretti1, Chris Wymant1, Michelle Kendall1, Lele Zhao1  +5 moreInstitutions (1)
31 Mar 2020-Science
Abstract: The newly emergent human virus SARS-CoV-2 (severe acute respiratory syndrome-coronavirus 2) is resulting in high fatality rates and incapacitated health systems. Preventing further transmission is a priority. We analyzed key parameters of epidemic spread to estimate the contribution of different transmission routes and determine requirements for case isolation and contact tracing needed to stop the epidemic. Although SARS-CoV-2 is spreading too fast to be contained by manual contact tracing, it could be controlled if this process were faster, more efficient, and happened at scale. A contact-tracing app that builds a memory of proximity contacts and immediately notifies contacts of positive cases can achieve epidemic control if used by enough people. By targeting recommendations to only those at risk, epidemics could be contained without resorting to mass quarantines ("lockdowns") that are harmful to society. We discuss the ethical requirements for an intervention of this kind.

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Topics: Contact tracing (51%)

1,692 Citations


Open accessJournal ArticleDOI: 10.1016/S0140-6736(20)30374-3
David L Heymann1, Nahoko Shindo2Institutions (2)
22 Feb 2020-The Lancet
Abstract: 542 www.thelancet.com Vol 395 February 22, 2020 The WHO Scientific and Technical Advisory Group for Infectious Hazards (STAG-IH), working with the WHO secretariat, reviewed available information about the outbreaks of 2019 novel coronavirus disease (COVID-19) on Feb 7, 2020, in Geneva, Switzerland, and concluded that the continuing strategy of containment for elimination should continue, and that the coming 2–3 weeks through to the end of February, 2020, will be crucial to monitor the situation of community transmission to update WHO public health recommendations if required. Genetic analysis early in the outbreak of COVID-19 in China revealed that the virus was similar to, but distinct from, severe acute respiratory syndrome coronavirus (SARS-CoV), but the closest genetic similarity was found in a coronavirus that had been COVID-19: what is next for public health? U-Report to identify how and where young people wish to be involved in advancing the goal of promoting mental health and wellbeing in their communities and wider society. Alongside scalability, a need exists for inclusive tools that allow for genuine and meaningful engagement from children in rural areas, ethnic minorities, gender and sexual minorities, those exposed to poverty and violence, and those who experience health challenges. In our work with the Lancet Commission on Global Mental Health and Sustainable Development on the My Mind Our Humanity campaign, arts-based approaches have allowed us to engage young people from a range of backgrounds, both face-to-face and online. Poetry and music have created safe spaces for sharing deeply personal experiences of mental health challenges and supporting each other. These approaches have allowed us to challenge stigma by reminding young people of our shared humanity. The potential of artsbased and digital tools to foster inclusive engagement and participation is important, and our capacity to empower young generations is dependent on our ability to harness these and other resources to understand their values and experiences. The WHO–UNICEF–Lancet Commission invites us to think holistically about children and their rights to be heard and respected, and emphasises the role of community engagement in promoting the health and development of the world’s children. Children’s participation goes far beyond formal, high-level platforms. Having a voice—or lacking one—defines every relationship and interaction children experience at home and in school, work, leisure settings, and other spaces they inhabit. Children are empowered when they feel safe and welcome at home and school; when they have someone to talk to if something is wrong; and when family, friends, and teachers hear their concerns and appreciate their ideas. Indeed, family togetherness and connection to one’s culture are crucial for health and wellbeing, according to the children consulted by the Commission, from communities across New Zealand, Lebanon, Nigeria, and Argentina. The potential of shared experiences to harness children’s health and wellbeing is enormous. By fostering a culture of connectedness and mutual respect, we meet children’s needs for self-esteem and confidence and strengthen their ability to make a difference. The WHO–UNICEF–Lancet Commission presents a candid assessment of the threats children face and the sombre implications for their future. But the Commission also presents a clear vision for making a better world, for them and with them. Too often have we seen young people sidelined while those who have the power to make a change hesitate. For too long have young people been silenced, mocked, and judged for their bold ambitions to challenge the status quo. We will not be deterred. Now and always, the voices of children will call for an inclusive, fair, and sustainable future.

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Topics: Betacoronavirus (57%), Viral Epidemiology (57%), Pneumonia (51%)

654 Citations


Open accessJournal ArticleDOI: 10.1016/S1473-3099(20)30162-6
Joel R Koo1, Alex R. Cook1, Minah Park1, Yinxiaohe Sun1  +5 moreInstitutions (2)
Abstract: Summary Background Since the coronavirus disease 2019 outbreak began in the Chinese city of Wuhan on Dec 31, 2019, 68 imported cases and 175 locally acquired infections have been reported in Singapore. We aimed to investigate options for early intervention in Singapore should local containment (eg, preventing disease spread through contact tracing efforts) be unsuccessful. Methods We adapted an influenza epidemic simulation model to estimate the likelihood of human-to-human transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in a simulated Singaporean population. Using this model, we estimated the cumulative number of SARS-CoV-2 infections at 80 days, after detection of 100 cases of community transmission, under three infectivity scenarios (basic reproduction number [R0] of 1·5, 2·0, or 2·5) and assuming 7·5% of infections are asymptomatic. We first ran the model assuming no intervention was in place (baseline scenario), and then assessed the effect of four intervention scenarios compared with a baseline scenario on the size and progression of the outbreak for each R0 value. These scenarios included isolation measures for infected individuals and quarantining of family members (hereafter referred to as quarantine); quarantine plus school closure; quarantine plus workplace distancing; and quarantine, school closure, and workplace distancing (hereafter referred to as the combined intervention). We also did sensitivity analyses by altering the asymptomatic fraction of infections (22·7%, 30·0%, 40·0%, and 50·0%) to compare outbreak sizes under the same control measures. Findings For the baseline scenario, when R0 was 1·5, the median cumulative number of infections at day 80 was 279 000 (IQR 245 000–320 000), corresponding to 7·4% (IQR 6·5–8·5) of the resident population of Singapore. The median number of infections increased with higher infectivity: 727 000 cases (670 000–776 000) when R0 was 2·0, corresponding to 19·3% (17·8–20·6) of the Singaporean population, and 1 207 000 cases (1 164 000–1 249 000) when R0 was 2·5, corresponding to 32% (30·9–33·1) of the Singaporean population. Compared with the baseline scenario, the combined intervention was the most effective, reducing the estimated median number of infections by 99·3% (IQR 92·6–99·9) when R0 was 1·5, by 93·0% (81·5–99·7) when R0 was 2·0, and by 78·2% (59·0 −94·4) when R0 was 2·5. Assuming increasing asymptomatic fractions up to 50·0%, up to 277 000 infections were estimated to occur at day 80 with the combined intervention relative to 1800 for the baseline at R0 of 1·5. Interpretation Implementing the combined intervention of quarantining infected individuals and their family members, workplace distancing, and school closure once community transmission has been detected could substantially reduce the number of SARS-CoV-2 infections. We therefore recommend immediate deployment of this strategy if local secondary transmission is confirmed within Singapore. However, quarantine and workplace distancing should be prioritised over school closure because at this early stage, symptomatic children have higher withdrawal rates from school than do symptomatic adults from work. At higher asymptomatic proportions, intervention effectiveness might be substantially reduced requiring the need for effective case management and treatments, and preventive measures such as vaccines. Funding Singapore Ministry of Health, Singapore Population Health Improvement Centre.

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Topics: Population (54%)

453 Citations


Open accessJournal ArticleDOI: 10.1126/SCIENCE.ABC0035
12 Jun 2020-Science
Abstract: The ongoing coronavirus disease 2019 (COVID-19) pandemic poses a severe threat to public health worldwide. We combine data on demography, contact patterns, disease severity, and health care capacity and quality to understand its impact and inform strategies for its control. Younger populations in lower-income countries may reduce overall risk, but limited health system capacity coupled with closer intergenerational contact largely negates this benefit. Mitigation strategies that slow but do not interrupt transmission will still lead to COVID-19 epidemics rapidly overwhelming health systems, with substantial excess deaths in lower-income countries resulting from the poorer health care available. Of countries that have undertaken suppression to date, lower-income countries have acted earlier. However, this will need to be maintained or triggered more frequently in these settings to keep below available health capacity, with associated detrimental consequences for the wider health, well-being, and economies of these countries.

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Topics: Health care (57%), Global health (57%), Public health (56%)

428 Citations