scholarly journals Tracing contacts to evaluate the transmission of COVID-19 from highly exposed individuals in public transportation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Caio Ponte ◽  
Humberto A. Carmona ◽  
Erneson A. Oliveira ◽  
Carlos Caminha ◽  
Antonio S. Lima ◽  
...  
Keyword(s):  
Public Transportation ◽  
Healthcare Workers ◽  
Time Windows ◽  
Mean Field ◽  
Contact Tracing ◽  
Reproduction Numbers ◽  
Consecutive Time ◽  
Longitudinal Comparison ◽  
The City ◽  
Close Contacts

AbstractWe investigate, through a data-driven contact tracing model, the transmission of COVID-19 inside buses during distinct phases of the pandemic in a large Brazilian city. From this microscopic approach, we recover the networks of close contacts within consecutive time windows. A longitudinal comparison is then performed by upscaling the traced contacts with the transmission computed from a mean-field compartmental model for the entire city. Our results show that the effective reproduction numbers inside the buses, $$Re^{bus}$$ R e bus , and in the city, $$Re^{city}$$ R e city , followed a compatible behavior during the first wave of the local outbreak. Moreover, by distinguishing the close contacts of healthcare workers in the buses, we discovered that their transmission, $$Re^{health}$$ R e health , during the same period, was systematically higher than $$Re^{bus}$$ R e bus . This result reinforces the need for special public transportation policies for highly exposed groups of people.

scholarly journals Tracing contacts to evaluate the transmission of COVID-19 from highly exposed individuals in public transportation

2021 ◽  
Author(s):  
Caio Ponte ◽  
Humberto Carmona ◽  
Erneson Oliveira ◽  
Carlos Caminha ◽  
Antonio Lima Neto ◽  
...  
Keyword(s):  
Public Transportation ◽  
Healthcare Workers ◽  
Time Windows ◽  
Mean Field ◽  
Contact Tracing ◽  
Reproduction Numbers ◽  
Consecutive Time ◽  
Longitudinal Comparison ◽  
The City ◽  
Close Contacts

We investigate, through a data-driven contact tracing model, the transmission of COVID-19 inside buses during distinct phases of the pandemic in a large Brazilian city. From this microscopic approach, we recover the networks of close contacts within consecutive time windows. A longitudinal comparison is then performed by upscaling the traced contacts with the transmission computed from a mean-field compartmental model for the entire city. Our results show that the effective reproduction numbers inside the buses, Rebus, and in the city, Recity, followed a compatible behavior during the first wave of the local outbreak. Moreover, by distinguishing the close contacts of healthcare workers in the buses, we discovered that their transmission, Rehealth, during the same period, was systematically higher than Rebus. This result reinforces the need for special public transportation policies for highly exposed groups of people.

scholarly journals Estimation of effects of contact tracing and mask adoption on COVID-19 transmission in San Francisco: a modeling study

2020 ◽  
Author(s):  
Lee Worden ◽  
Rae Wannier ◽  
Seth Blumberg ◽  
Alex Y. Ge ◽  
George W. Rutherford ◽  
...  
Keyword(s):  
San Francisco ◽  
Statistical Estimation ◽  
Detection Rate ◽  
Reproduction Number ◽  
Contact Tracing ◽  
Reproduction Numbers ◽  
The Impact ◽  
The City ◽  
Testing Coverage ◽  
Over Time

AbstractThe current COVID-19 pandemic has spurred concern about what interventions may be effective at reducing transmission. The city and county of San Francisco imposed a shelter-in-place order in March 2020, followed by use of a contact tracing program and a policy requiring use of cloth face masks. We used statistical estimation and simulation to estimate the effectiveness of these interventions in San Francisco. We estimated that self-isolation and other practices beginning at the time of San Francisco’s shelter-in-place order reduced the effective reproduction number of COVID-19 by 35.4% (95% CI, −20.1%–81.4%). We estimated the effect of contact tracing on the effective reproduction number to be a reduction of approximately 44% times the fraction of cases that are detected, which may be modest if the detection rate is low. We estimated the impact of cloth mask adoption on reproduction number to be approximately 8.6%, and note that the benefit of mask adoption may be substantially greater for essential workers and other vulnerable populations, residents return to circulating outside the home more often. We estimated the effect of those interventions on incidence by simulating counterfactual scenarios in which contact tracing was not adopted, cloth masks were not adopted, and neither contact tracing nor cloth masks was adopted, and found increases in case counts that were modest, but relatively larger than the effects on reproduction numbers. These estimates and model results suggest that testing coverage and timing of testing and contact tracing may be important, and that modest effects on reproduction numbers can nonetheless cause substantial effects on case counts over time.

scholarly journals Source and symptoms of COVID-19 among hospital workers in Milan

2020 ◽  
Vol 70 (9) ◽  
pp. 672-679 ◽  
Author(s):  
S Mandić-Rajčević ◽  
F Masci ◽  
E Crespi ◽  
S Franchetti ◽  
A Longo ◽  
...  
Keyword(s):  
Healthcare Workers ◽  
Case Series ◽  
Nursing Assistants ◽  
Vulnerable Groups ◽  
Contact Tracing ◽  
Public Healthcare ◽  
Nasopharyngeal Swab ◽  
Infection Rates ◽  
Sources Of Infection ◽  
Close Contacts

Abstract Background Healthcare workers (HCWs) are commonly infected by SARS-CoV-2 and represent one of the most vulnerable groups. Adequate prevention strategies are necessary to guarantee HCWs’ safety, as well as to prevent dissemination of the infection among patients. Aims To describe a case series of SARS-CoV-2-positive HCWs in a large public healthcare organization in Milan (Italy) during the most devastating weeks of the epidemic and analyse the sources, symptoms and duration of SARS-CoV-2 infection. Methods This study included 172 SARS-CoV-2-positive HCWs who were infected between the 25th of February and the 7th of April 2020. A nasopharyngeal swab (NPS) and RT-PCR were used to indicate. Results Initially, the most common sources of infection were other positive HCWs (49%). Medical doctors and nursing assistants were most frequently infected, with infection rates of 53/1000 and 50/1000, respectively. COVID-19 departments were less affected than internal medicine, surgery, intensive care, or emergency room. The most commonly reported symptom was mild cough, while loss of smell (anosmia) and loss of taste (ageusia) were reported as moderate and severe by 30–40% of HCWs. The time necessary for 50% of workers to recover from the infection was 23 days, while it took 41 days for 95% of HCWs to become virus-free. Conclusions HCWs are commonly infected due to close contacts with other positive HCWs, and non-COVID departments were most affected. Most HCWs were asymptomatic or subclinical but contact tracing and testing of asymptomatic HCWs help identify and isolate infected workers.

The first 2 months of COVID-19 contact tracing in the Northern Territory of Australia, March–April 2020

2020 ◽  
Vol 44 ◽  
Author(s):  
Anthony DK Draper ◽  
Karen E Dempsey ◽  
Rowena H Boyd ◽  
Emma M Childs ◽  
Hayley M Black ◽  
...  
Keyword(s):  
Disease Control ◽  
Healthcare Workers ◽  
Northern Territory ◽  
Contact Tracing ◽  
Cruise Ship ◽  
Disease Symptoms ◽  
Household Contacts ◽  
Close Contacts

The Northern Territory (NT) Centre for Disease Control (CDC) undertook contact tracing of all notified cases of coronavirus disease 2019 (COVID-19) within the Territory. There were 28 cases of COVID-19 notified in the NT between 1 March and 30 April 2020. In total 527 people were identified as close contacts over the same period; 493 were successfully contacted; 445 were located in the NT and were subsequently quarantined and monitored for disease symptoms daily for 14 days after contact with a confirmed COVID-19 case. Of these 445 close contacts, 4 tested positive for COVID-19 after developing symptoms; 2/46 contacts who were cruise ship passengers (4.3%, 95% CI 0.5–14.8%) and 2/51 household contacts (3.9%, 95% CI 0.5–13.5%). None of the 326 aircraft passengers or 4 healthcare workers who were being monitored in the NT as close contacts became cases.

scholarly journals Epidemiological characteristics of COVID-19 cases among Indians residing in Kuwait

2021 ◽  
Author(s):  
Jagan K. Baskaradoss ◽  
Aishah Alsumait ◽  
Shaheer Malik ◽  
Jitendra Ariga ◽  
Amrita Geevarghese ◽  
...  
Keyword(s):  
Healthcare Workers ◽  
Contact Tracing ◽  
Indian Community ◽  
Asymptomatic Patients ◽  
Serial Interval ◽  
The World ◽  
Early Increase ◽  
The Mean ◽  
Epidemiological Characteristics ◽  
Close Contacts

Background: The coronavirus disease 2019 (COVID-19) pandemic has rapidly spread to most countries around the world. Disproportionate spread of COVID-19 among the Indian community in Kuwait prompted heightened surveillance in this community. Aims: To study the epidemiological characteristics of COVID-19 patients and their contacts among the Indian community in Kuwait. Methods: Data collection was done as a part of contact tracing efforts undertaken by the Kuwaiti Ministry of Health. Results: We analysed contact-tracing data for the initial 1348 laboratory-confirmed Indian patients and 6357 contacts (5681 close and 676 casual). The mean (standard deviation) age of the patients was 39.43 (10.5) years and 76.5% of the cases were asymptomatic or had only mild symptoms. Asymptomatic patients were significantly older [40.05 (10.42) years] than patients with severe symptoms [37.54 (10.54) years] (P = 0.024). About 70% of the patients were living in shared accommodation. Most of the close contacts were living in the same household, as compared with casual contacts, who were primarily workplace contacts (P < 0.001). Among the different occupations, healthcare workers had the highest proportion of cases (18.4%). Among the 216 pairs of cases with a clear relationship between the index and secondary cases, the mean serial interval was estimated to be 3.89 (3.69) days, with a median of 3 and interquartile range of 1–5 days. Conclusion: An early increase in the number of COVID-19 cases among the Indian community could be primarily attributed to crowded living conditions and the high proportion of healthcare workers in this community.

scholarly journals Spatiotemporal tracing of pandemic spread from infection data

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Satyaki Roy ◽  
Preetom Biswas ◽  
Preetam Ghosh
Keyword(s):  
New York ◽  
Network Inference ◽  
Spatial Interaction ◽  
Time Windows ◽  
New York State ◽  
Mitigation Measures ◽  
Contact Tracing ◽  
Long Distance ◽  
Spatiotemporal Models ◽  
Spread Of Infection

AbstractCOVID-19, a global pandemic caused by the Severe Acute Respiratory Syndrome Coronavirus 2 virus, has claimed millions of lives worldwide. Amid soaring contagion due to newer strains of the virus, it is imperative to design dynamic, spatiotemporal models to contain the spread of infection during future outbreaks of the same or variants of the virus. The reliance on existing prediction and contact tracing approaches on prior knowledge of inter- or intra-zone mobility renders them impracticable. We present a spatiotemporal approach that employs a network inference approach with sliding time windows solely on the date and number of daily infection numbers of zones within a geographical region to generate temporal networks capturing the influence of each zone on another. It helps analyze the spatial interaction among the hotspot or spreader zones and highly affected zones based on the flow of network contagion traffic. We apply the proposed approach to the daily infection counts of New York State as well as the states of USA to show that it effectively measures the phase shifts in the pandemic timeline. It identifies the spreaders and affected zones at different time points and helps infer the trajectory of the pandemic spread across the country. A small set of zones periodically exhibit a very high outflow of contagion traffic over time, suggesting that they act as the key spreaders of infection. Moreover, the strong influence between the majority of non-neighbor regions suggests that the overall spread of infection is a result of the unavoidable long-distance trips by a large number of people as opposed to the shorter trips at a county level, thereby informing future mitigation measures and public policies.

scholarly journals Selecting Freight Transportation Modes in Last-Mile Urban Distribution in Pamplona (Spain): An Option for Drone Delivery in Smart Cities

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4748
Author(s):  
Adrian Serrano-Hernandez ◽  
Aitor Ballano ◽  
Javier Faulin
Keyword(s):  
Public Transportation ◽  
Smart Cities ◽  
Freight Transportation ◽  
City Center ◽  
Analytic Hierarchy ◽  
Freight Logistics ◽  
Transportation Modes ◽  
Last Mile ◽  
Urban Distribution ◽  
The City

Urban distribution in medium-sized cities faces a major challenge, mainly when deliveries are difficult in the city center due to: an increase of e-commerce, weak public transportation system, and the promotion of urban sustainability plans. As a result, private cars, public transportation, and freight transportation compete for the same space. This paper analyses the current state for freight logistics in the city center of Pamplona (Spain) and proposes alternative transportation routes and transportation modes in the last-mile city center distribution according to different criteria evaluated by residents. An analytic hierarchy process (AHP) was developed. A number of alternatives have been assessed considering routes and transportation modes: the shortest route criterion and avoiding some city center area policies are combined with traditional van-based, bike, and aerial (drone) distribution protocols for delivering parcels and bar/restaurant supplies. These alternatives have been evaluated within a multicriteria framework in which economic, environmental, and social objectives are considered at the same time. The point in this multicriteria framework is that the criteria/alternative AHP weights and priorities have been set according to a survey deployed in the city of Pamplona (Navarre, Spain). The survey and AHP results show the preference for the use of drone or bike distribution in city center in order to reduce social and environmental issues.

scholarly journals Assessing testing strategies and duration of quarantine in contact tracing for SARS-CoV-2: a retrospective study of San Francisco’s COVID-19 contact tracing program, June- August, 2020

2021 ◽  
Author(s):  
M J A Reid ◽  
P Prado ◽  
H Brosnan ◽  
A Ernst ◽  
H Spindler ◽  
...  
Keyword(s):  
Retrospective Study ◽  
San Francisco ◽  
Contact Tracing ◽  
Testing Strategies ◽  
Close Contacts

Abstract We sought to assess the proportion of elicited close contacts diagnosed with COVID-19 at the start, and before exiting quarantine, in San Francisco, USA. From June 8th to August 31st, 6946 contacts were identified; 3008 (46.3%) tested, 940 (13.5%) tested positive; 90% tested positive in first 9 days of quarantine.

scholarly journals Methicillin-Resistant Staphylococcus aureus Prevalence Among Healthcare Workers in Contact Tracings in a Dutch Hospital

2020 ◽  
Vol 41 (S1) ◽  
pp. s316-s317
Author(s):  
Veronica Weterings ◽  
Heidi Kievits ◽  
Miranda van Rijen ◽  
Jan Kluytmans
Keyword(s):  
Staphylococcus Aureus ◽  
The Netherlands ◽  
Healthcare Workers ◽  
Index Case ◽  
Contact Tracing ◽  
Secondary Case ◽  
National Guidelines ◽  
Carriage Rate ◽  
Methicillin Resistant ◽  
Mlva Type

Background: In The Netherlands, the national guidelines on Methicillin-Resistant Staphylococcus aureus (MRSA) prevention and control advocate screening of healthcare workers (HCWs) after unprotected exposure to MRSA carriers. Although this strategy is largely successful, contact tracing of staff is a time-consuming and costly component. We evaluated our contact tracing policy for HCWs over the years 2010–2018. Methods: A retrospective, observational study was performed in a Dutch teaching hospital. All HCWs who had unprotected contact with an MRSA carrier were included in contact tracing. When there had been a long period of unprotected admission prior to an MRSA finding, or when the index case was an HCW, the entire (nursing) team was tested. All samples of HCWs who were tested for MRSA carriage as part of contact tracing from 2010 until 2018 were included. A pooled nose, throat, and perineum swab was collected using the eSwab medium (Copan) and inoculated on chromID MRSA agar plates (bioMérieux) after enrichment in a broth. Molecular typing was performed using multiple-locus variable number of tandem repeat analysis (MLVA). Results: In total, we included 8,849 samples (range, 677–1,448 samples per year) from 287 contact tracings (range, 26–55 contact tracings per year). Overall, 32 HCWs were colonized with MRSA (0.36%; 95% CI, 0.26%–0.51%). None of them developed a clinical infection. Moreover, 8 HCWs (0.10%; 95% CI, 0.05%–0.19%) were colonized with the same MLVA type as the index case and were detected in 6 of 287 contact tracings (2%). In 4 of 8 of these cases, a positive HCW was the index for undertaking contact tracing. In 3 of 8 cases, it was clear that the HCW who was identified in the contact tracing was the source of the outbreak and was the cause of invasive MRSA infections in patients. Notably, a different MLVA type as the index case was found in 24 HCWs (0.27%; 95% CI, 0.18%–0.40%) of whom 7 of 24 HCWs (29.2%) were intermittent carriers. Conclusions: This study revealed a sustained low MRSA prevalence among samples in contact tracing of HCWs over 9 years. Furthermore, it shows that when MRSA contact tracing is performed according to the national guideline, only 1 of 1,000 samples results in a secondary case. This is similar to the population carriage rate of MRSA in The Netherlands. More frequently, an unrelated strain is found. These findings raise questions regarding the efficacy of the current strategy to perform contact tracing after unprotected exposure.Funding: NoneDisclosures: None

scholarly journals A Novel Deep Learning Approach for Machinery Prognostics Based on Time Windows

2019 ◽  
Vol 9 (22) ◽  
pp. 4813 ◽  
Author(s):  
Hanbo Yang ◽  
Fei Zhao ◽  
Gedong Jiang ◽  
Zheng Sun ◽  
Xuesong Mei
Keyword(s):  
Time Windows ◽  
Remaining Useful Life ◽  
Sensor Data ◽  
Time Interval ◽  
Kernel Module ◽  
Initial Stage ◽  
Research Task ◽  
Consecutive Time ◽  
Useful Life

Remaining useful life (RUL) prediction is a challenging research task in prognostics and receives extensive attention from academia to industry. This paper proposes a novel deep convolutional neural network (CNN) for RUL prediction. Unlike health indicator-based methods which require the long-term tracking of sensor data from the initial stage, the proposed network aims to utilize data from consecutive time samples at any time interval for RUL prediction. Additionally, a new kernel module for prognostics is designed where the kernels are selected automatically, which can further enhance the feature extraction ability of the network. The effectiveness of the proposed network is validated using the C-MAPSS dataset for aircraft engines provided by NASA. Compared with the state-of-the-art results on the same dataset, the prediction results demonstrate the superiority of the proposed network.

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