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1.
Infect Dis Poverty ; 9(1): 83, 2020 Jul 06.
Article in English | MEDLINE | ID: covidwho-657687

ABSTRACT

BACKGROUND: The coronavirus disease 2019 (COVID-19) outbreak has seriously endangered the health and lives of Chinese people. In this study, we predicted the COVID-19 epidemic trend and estimated the efficacy of several intervention strategies in the mainland of China. METHODS: According to the COVID-19 epidemic status, we constructed a compartmental model. Based on reported data from the National Health Commission of People's Republic of China during January 10-February 17, 2020, we estimated the model parameters. We then predicted the epidemic trend and transmission risk of COVID-19. Using a sensitivity analysis method, we estimated the efficacy of several intervention strategies. RESULTS: The cumulative number of confirmed cases in the mainland of China will be 86 763 (95% CI: 86 067-87 460) on May 2, 2020. Up until March 15, 2020, the case fatality rate increased to 6.42% (95% CI: 6.16-6.68%). On February 23, 2020, the existing confirmed cases reached its peak, with 60 890 cases (95% CI: 60 350-61 431). On January 23, 2020, the effective reproduction number was 2.620 (95% CI: 2.567-2.676) and had dropped below 1.0 since February 5, 2020. Due to governmental intervention, the total number of confirmed cases was reduced by 99.85% on May 2, 2020. Had the isolation been relaxed from February 24, 2020, there might have been a second peak of infection. However, relaxing the isolation after March 16, 2020 greatly reduced the number of existing confirmed cases and deaths. The total number of confirmed cases and deaths would increase by 8.72 and 9.44%, respectively, due to a 1-day delayed diagnosis in non-isolated infected patients. Moreover, if the coverage of close contact tracing was increased to 100%, the cumulative number of confirmed cases would be decreased by 88.26% on May 2, 2020. CONCLUSIONS: The quarantine measures adopted by the Chinese government since January 23, 2020 were necessary and effective. Postponing the relaxation of isolation, early diagnosis, patient isolation, broad close-contact tracing, and strict monitoring of infected persons could effectively control the COVID-19 epidemic. April 1, 2020 would be a reasonable date to lift quarantine in Hubei and Wuhan.


Subject(s)
Communicable Disease Control/methods , Coronavirus Infections/prevention & control , Coronavirus Infections/transmission , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Pneumonia, Viral/transmission , Betacoronavirus , China/epidemiology , Communicable Disease Control/legislation & jurisprudence , Coronavirus Infections/epidemiology , Disease Transmission, Infectious/legislation & jurisprudence , Disease Transmission, Infectious/prevention & control , Disease Transmission, Infectious/statistics & numerical data , Forecasting , Humans , Models, Statistical , National Health Programs/statistics & numerical data , Pneumonia, Viral/epidemiology
2.
Swiss Med Wkly ; 150: w20313, 2020 07 13.
Article in English | MEDLINE | ID: covidwho-651678

ABSTRACT

The reproduction number is broadly considered as a key indicator for the spreading of the COVID-19 pandemic. Its estimated value is a measure of the necessity and, eventually, effectiveness of interventions imposed in various countries. Here we present an online tool for the data-driven inference and quantification of uncertainties for the reproduction number, as well as the time points of interventions for 51 European countries. The study relied on the Bayesian calibration of the SIR model with data from reported daily infections from these countries. The model fitted the data, for most countries, without individual tuning of parameters. We also compared the results of SIR and SEIR models, which give different estimates of the reproduction number, and provided an analytical relationship between the respective numbers. We deployed a Bayesian inference framework with efficient sampling algorithms, to present a publicly available graphical user interface (https://cse-lab.ethz.ch/coronavirus) that allows the user to assess and compare predictions for pairs of European countries. The results quantified the rate of the disease’s spread before and after interventions, and provided a metric for the effectiveness of non-pharmaceutical interventions in different countries. They also indicated how geographic proximity and the times of interventions affected the progression of the epidemic.


Subject(s)
Basic Reproduction Number/statistics & numerical data , Coronavirus Infections , Disease Transmission, Infectious/statistics & numerical data , Epidemiological Monitoring , Pandemics , Pneumonia, Viral , Bayes Theorem , Betacoronavirus/isolation & purification , Communicable Disease Control/methods , Communicable Disease Control/statistics & numerical data , Coronavirus Infections/epidemiology , Coronavirus Infections/prevention & control , Coronavirus Infections/transmission , Disease Transmission, Infectious/prevention & control , Epidemiologic Measurements , Europe/epidemiology , Humans , Pandemics/prevention & control , Pandemics/statistics & numerical data , Pneumonia, Viral/epidemiology , Pneumonia, Viral/prevention & control , Pneumonia, Viral/transmission , Uncertainty
4.
Infect Dis Poverty ; 9(1): 87, 2020 Jul 10.
Article in English | MEDLINE | ID: covidwho-640469

ABSTRACT

BACKGROUND: The new coronavirus disease COVID-19 began in December 2019 and has spread rapidly by human-to-human transmission. This study evaluated the transmissibility of the infectious disease and analyzed its association with temperature and humidity to study the propagation pattern of COVID-19. METHODS: In this study, we revised the reported data in Wuhan based on several assumptions to estimate the actual number of confirmed cases considering that perhaps not all cases could be detected and reported in the complex situation there. Then we used the equation derived from the Susceptible-Exposed-Infectious-Recovered (SEIR) model to calculate R0 from January 24, 2020 to February 13, 2020 in 11 major cities in China for comparison. With the calculation results, we conducted correlation analysis and regression analysis between R0 and temperature and humidity for four major cities in China to see the association between the transmissibility of COVID-19 and the weather variables. RESULTS: It was estimated that the cumulative number of confirmed cases had exceeded 45 000 by February 13, 2020 in Wuhan. The average R0 in Wuhan was 2.7, significantly higher than those in other cities ranging from 1.8 to 2.4. The inflection points in the cities outside Hubei Province were between January 30, 2020 and February 3, 2020, while there had not been an obvious downward trend of R0 in Wuhan. R0 negatively correlated with both temperature and humidity, which was significant at the 0.01 level. CONCLUSIONS: The transmissibility of COVID-19 was strong and importance should be attached to the intervention of its transmission especially in Wuhan. According to the correlation between R0 and weather, the spread of disease will be suppressed as the weather warms.


Subject(s)
Basic Reproduction Number , Coronavirus Infections/epidemiology , Coronavirus Infections/transmission , Pneumonia, Viral/epidemiology , Pneumonia, Viral/transmission , Betacoronavirus/pathogenicity , China/epidemiology , Cities , Coronavirus Infections/prevention & control , Disease Transmission, Infectious/prevention & control , Disease Transmission, Infectious/statistics & numerical data , Humans , Humidity , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Regression Analysis , Temperature
8.
Proc Natl Acad Sci U S A ; 117(26): 14857-14863, 2020 06 30.
Article in English | MEDLINE | ID: covidwho-595563

ABSTRACT

Various mitigation measures have been implemented to fight the coronavirus disease 2019 (COVID-19) pandemic, including widely adopted social distancing and mandated face covering. However, assessing the effectiveness of those intervention practices hinges on the understanding of virus transmission, which remains uncertain. Here we show that airborne transmission is highly virulent and represents the dominant route to spread the disease. By analyzing the trend and mitigation measures in Wuhan, China, Italy, and New York City, from January 23 to May 9, 2020, we illustrate that the impacts of mitigation measures are discernable from the trends of the pandemic. Our analysis reveals that the difference with and without mandated face covering represents the determinant in shaping the pandemic trends in the three epicenters. This protective measure alone significantly reduced the number of infections, that is, by over 78,000 in Italy from April 6 to May 9 and over 66,000 in New York City from April 17 to May 9. Other mitigation measures, such as social distancing implemented in the United States, are insufficient by themselves in protecting the public. We conclude that wearing of face masks in public corresponds to the most effective means to prevent interhuman transmission, and this inexpensive practice, in conjunction with simultaneous social distancing, quarantine, and contact tracing, represents the most likely fighting opportunity to stop the COVID-19 pandemic. Our work also highlights the fact that sound science is essential in decision-making for the current and future public health pandemics.


Subject(s)
Coronavirus Infections/transmission , Disease Transmission, Infectious/statistics & numerical data , Inhalation Exposure/statistics & numerical data , Pneumonia, Viral/transmission , Coronavirus Infections/epidemiology , Disease Transmission, Infectious/classification , Disease Transmission, Infectious/prevention & control , Humans , Inhalation Exposure/prevention & control , Masks/statistics & numerical data , Pandemics , Pneumonia, Viral/epidemiology , Primary Prevention/methods , Primary Prevention/statistics & numerical data , Quarantine/methods , Quarantine/statistics & numerical data , Respiratory Protective Devices/statistics & numerical data , United States
10.
Proc Natl Acad Sci U S A ; 117(26): 14642-14644, 2020 06 30.
Article in English | MEDLINE | ID: covidwho-595209

ABSTRACT

To prevent the spread of coronavirus disease 2019 (COVID-19), some types of public spaces have been shut down while others remain open. These decisions constitute a judgment about the relative danger and benefits of those locations. Using mobility data from a large sample of smartphones, nationally representative consumer preference surveys, and economic statistics, we measure the relative transmission reduction benefit and social cost of closing 26 categories of US locations. Our categories include types of shops, entertainments, and service providers. We rank categories by their trade-off of social benefits and transmission risk via dominance across 13 dimensions of risk and importance and through composite indexes. We find that, from February to March 2020, there were larger declines in visits to locations that our measures indicate should be closed first.


Subject(s)
Behavior , Coronavirus Infections/prevention & control , Disease Transmission, Infectious/prevention & control , Inhalation Exposure/prevention & control , Models, Statistical , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Primary Prevention/statistics & numerical data , Quarantine/statistics & numerical data , Confined Spaces , Contact Tracing/methods , Contact Tracing/statistics & numerical data , Coronavirus Infections/epidemiology , Coronavirus Infections/transmission , Costs and Cost Analysis , Disease Transmission, Infectious/statistics & numerical data , Humans , Inhalation Exposure/statistics & numerical data , Museums , Pneumonia, Viral/epidemiology , Pneumonia, Viral/transmission , Primary Prevention/economics , Primary Prevention/methods , Quarantine/economics , Quarantine/methods , Risk Assessment , Schools , Smartphone/statistics & numerical data , Sports and Recreational Facilities , United States
11.
Swiss Med Wkly ; 150: w20295, 2020 05 18.
Article in English | MEDLINE | ID: covidwho-425097

ABSTRACT

Following the rapid dissemination of COVID-19 cases in Switzerland, large-scale non-pharmaceutical interventions (NPIs) were implemented by the cantons and the federal government between 28 February and 20 March 2020. Estimates of the impact of these interventions on SARS-CoV-2 transmission are critical for decision making in this and future outbreaks. We here aim to assess the impact of these NPIs on disease transmission by estimating changes in the basic reproduction number (R0) at national and cantonal levels in relation to the timing of these NPIs. We estimated the time-varying R0 nationally and in eleven cantons by fitting a stochastic transmission model explicitly simulating within-hospital dynamics. We used individual-level data from more than 1000 hospitalised patients in Switzerland and public daily reports of hospitalisations and deaths. We estimated the national R0 to be 2.8 (95% confidence interval 2.1–3.8) at the beginning of the epidemic. Starting from around 7 March, we found a strong reduction in time-varying R0 with a 86% median decrease (95% quantile range [QR] 79–90%) to a value of 0.40 (95% QR 0.3–0.58) in the period of 29 March to 5 April. At the cantonal level, R0 decreased over the course of the epidemic between 53% and 92%. Reductions in time-varying R0 were synchronous with changes in mobility patterns as estimated through smartphone activity, which started before the official implementation of NPIs. We inferred that most of the reduction of transmission is attributable to behavioural changes as opposed to natural immunity, the latter accounting for only about 4% of the total reduction in effective transmission. As Switzerland considers relaxing some of the restrictions of social mixing, current estimates of time-varying R0 well below one are promising. However, as of 24 April 2020, at least 96% (95% QR 95.7–96.4%) of the Swiss population remains susceptible to SARS-CoV-2. These results warrant a cautious relaxation of social distance practices and close monitoring of changes in both the basic and effective reproduction numbers.


Subject(s)
Betacoronavirus/isolation & purification , Communicable Disease Control , Coronavirus Infections , Disease Transmission, Infectious , Pandemics/statistics & numerical data , Pneumonia, Viral , Communicable Disease Control/methods , Communicable Disease Control/organization & administration , Communicable Disease Control/statistics & numerical data , Communicable Diseases, Emerging/prevention & control , Coronavirus Infections/epidemiology , Coronavirus Infections/prevention & control , Coronavirus Infections/transmission , Disease Transmission, Infectious/prevention & control , Disease Transmission, Infectious/statistics & numerical data , Hospitalization/statistics & numerical data , Humans , Models, Statistical , Mortality , Pandemics/prevention & control , Pneumonia, Viral/epidemiology , Pneumonia, Viral/prevention & control , Pneumonia, Viral/transmission , Space-Time Clustering , Stochastic Processes
15.
Graefes Arch Clin Exp Ophthalmol ; 258(7): 1419-1426, 2020 Jul.
Article in English | MEDLINE | ID: covidwho-133580

ABSTRACT

PURPOSE: The coronavirus disease (COVID-19) pandemic has evolved into a formidable healthcare crisis. Ophthalmologists are at daily personal risk of acquiring and transmitting the virus. Implementation of official practical and protective guidelines can be challenging and is often absent. The purpose of this study was to describe the status of ophthalmology practice in Israel, at the early stages of the outbreak. METHODS: A 17-item questionnaire was distributed to ophthalmologists practicing in Israel. Data was obtained regarding demographics and clinical and surgical practice during the pandemic. RESULTS: One hundred and sixty-seven ophthalmologists completed the survey from all regions of Israel. The survey was distributed during the early stages of the outbreak. At this time, no official government guidelines were in place. Most respondents reported no reduction of elective clinic visits and surgeries and no utilization of triage questionnaires. COVID-19 guidelines were reportedly promulgated to hospital ophthalmologists but not to community and private physicians. Personal protective equipment (PPE) measures were reportedly utilized; however, many respondents often acquired them individually. A majority of respondents advocated that healthcare institutions limit clinic and surgery services to emergency services. CONCLUSION: During the critical early stages of the COVID-19 outbreak in Israel, this study emphasizes the delay in development of emergency guidelines, necessary to protect patients and ophthalmologists from this highly transmissible disease.


Subject(s)
Betacoronavirus , Coronavirus Infections/epidemiology , Disease Outbreaks , Disease Transmission, Infectious/prevention & control , Emergency Service, Hospital , Ophthalmologists/standards , Pneumonia, Viral/epidemiology , Adult , Coronavirus Infections/transmission , Disease Transmission, Infectious/statistics & numerical data , Female , Humans , Israel/epidemiology , Male , Middle Aged , Pandemics , Pneumonia, Viral/transmission , Surveys and Questionnaires
17.
Graefes Arch Clin Exp Ophthalmol ; 258(7): 1427-1436, 2020 Jul.
Article in English | MEDLINE | ID: covidwho-88497

ABSTRACT

PURPOSE: The Coronavirus (COVID-19) outbreak is rapidly emerging as a global health threat. With no proven vaccination or treatment, infection control measures are paramount. In this article, we aim to describe the impact of COVID-19 on our practice and share our strategies and guidelines to maintain a sustainable ophthalmology practice. METHODS: Tan Tock Seng Hospital (TTSH) Eye Centre is the only ophthalmology department supporting the National Centre for Infectious Diseases (NCID), which is the national screening center and the main center for management of COVID-19 patients in Singapore. Our guidelines during this outbreak are discussed. RESULTS: Challenges in different care settings in our ophthalmology practice have been identified and analyzed with practical solutions and guidelines implemented in anticipation of these challenges. First, to minimize cross-infection of COVID-19, stringent infection control measures were set up. These include personal protective equipment (PPE) for healthcare workers and routine cleaning of "high-touch" surfaces. Second, for outpatient care, a stringent dual screening and triaging process were carried out to identify high-risk patients, with proper isolation for such patients. Administrative measures to lower patient attendance and reschedule appointments were carried out. Third, inpatient and outpatient care were separated to minimize interactions. Last but not least, logistics and manpower plans were drawn up in anticipation of resource demands and measures to improve the mental well-being of staff were implemented. CONCLUSION: We hope our measures during this COVID-19 pandemic can help ophthalmologists globally and serve to guide and maintain safe access in ophthalmology clinics when faced with similar disease outbreaks.


Subject(s)
Betacoronavirus , Coronavirus Infections/epidemiology , Disease Transmission, Infectious/prevention & control , Ophthalmology/standards , Pandemics , Personal Protective Equipment/supply & distribution , Pneumonia, Viral/epidemiology , Coronavirus Infections/transmission , Disease Transmission, Infectious/statistics & numerical data , Humans , Pneumonia, Viral/transmission , Singapore/epidemiology
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