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1.
PLoS One ; 16(4): e0250110, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33852642

RESUMO

BACKGROUND: Prediction of the dynamics of new SARS-CoV-2 infections during the current COVID-19 pandemic is critical for public health planning of efficient health care allocation and monitoring the effects of policy interventions. We describe a new approach that forecasts the number of incident cases in the near future given past occurrences using only a small number of assumptions. METHODS: Our approach to forecasting future COVID-19 cases involves 1) modeling the observed incidence cases using a Poisson distribution for the daily incidence number, and a gamma distribution for the series interval; 2) estimating the effective reproduction number assuming its value stays constant during a short time interval; and 3) drawing future incidence cases from their posterior distributions, assuming that the current transmission rate will stay the same, or change by a certain degree. RESULTS: We apply our method to predicting the number of new COVID-19 cases in a single state in the U.S. and for a subset of counties within the state to demonstrate the utility of this method at varying scales of prediction. Our method produces reasonably accurate results when the effective reproduction number is distributed similarly in the future as in the past. Large deviations from the predicted results can imply that a change in policy or some other factors have occurred that have dramatically altered the disease transmission over time. CONCLUSION: We presented a modelling approach that we believe can be easily adopted by others, and immediately useful for local or state planning.


Assuntos
/epidemiologia , Número Básico de Reprodução , Transmissão de Doença Infecciosa/prevenção & controle , Transmissão de Doença Infecciosa/estatística & dados numéricos , Previsões , Humanos , Incidência , Modelos Estatísticos , Pandemias , Saúde Pública , Estados Unidos/epidemiologia
2.
Front Public Health ; 9: 587425, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33834012

RESUMO

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-COV-2), which is causing the coronavirus disease-2019 (COVID-19) pandemic, poses a global health threat. However, it is easy to confuse COVID-19 with seasonal influenza in preliminary clinical diagnosis. In this study, the differences between influenza and COVID-19 in epidemiological features, clinical manifestations, comorbidities and pathogen biology were comprehensively compared and analyzed. SARS-CoV-2 causes a higher proportion of pneumonia (90.67 vs. 17.07%) and acute respiratory distress syndrome (12.00 vs. 0%) than influenza A virus. The proportion of leukopenia for influenza patients was 31.71% compared with 12.00% for COVID-19 patients (P = 0.0096). The creatinine and creatine kinase were significantly elevated when there were COVID-19 patients. The basic reproductive number (R0) for SARS-CoV-2 is 2.38 compared with 1.28 for seasonal influenza A virus. The mutation rate of SARS-CoV-2 ranges from 1.12 × 10-3 to 6.25 × 10-3, while seasonal influenza virus has a lower evolutionary rate (0.60-2.00 × 10-6). Overall, this study compared the clinical features and outcomes of medically attended COVID-19 and influenza patients. In addition, the S477N and N439K mutations on spike may affect the affinity with receptor ACE2. This study will contribute to COVID-19 control and epidemic surveillance in the future.


Assuntos
Influenza Humana , Adulto , Número Básico de Reprodução , Humanos , Influenza Humana/diagnóstico , Pessoa de Meia-Idade , Pandemias , Pneumonia Viral/epidemiologia , /virologia
3.
JAMA Netw Open ; 4(4): e217097, 2021 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-33890990

RESUMO

Importance: A significant proportion of COVID-19 transmission occurs silently during the presymptomatic and asymptomatic stages of infection. Children, although important drivers of silent transmission, are not included in the current COVID-19 vaccination campaigns. Objective: To estimate the benefits of identifying silent infections among children as a proxy for their vaccination. Design, Setting, and Participants: This study used an age-structured disease transmission model, parameterized with census data and estimates from published literature, to simulate the estimated synergistic effect of interventions in reducing attack rates during the course of 1 year among a synthetic population representative of the US demographic composition. The population included 6 age groups of 0 to 4, 5 to 10, 11 to 18, 19 to 49, 50 to 64, and 65 years or older based on US census data. Data were analyzed from December 12, 2020, to February 26, 2021. Exposures: In addition to the isolation of symptomatic cases within 24 hours of symptom onset, vaccination of adults was implemented to reach a 40% to 60% coverage during 1 year with an efficacy of 95% against symptomatic and severe COVID-19. Main Outcomes and Measures: The combinations of proportion and speed for detecting silent infections among children that would suppress future attack rates to less than 5%. Results: In the base-case scenarios with an effective reproduction number Re = 1.2, a targeted approach that identifies 11% of silent infections among children within 2 days and 14% within 3 days after infection would bring attack rates to less than 5% with 40% vaccination coverage of adults. If silent infections among children remained undetected, achieving the same attack rates would require an unrealistically high vaccination coverage (≥81%) of this age group, in addition to 40% vaccination coverage of adults. The estimated effect of identifying silent infections was robust in sensitivity analyses with respect to vaccine efficacy against infection and reduced susceptibility of children to infection. Conclusions and Relevance: In this simulation modeling study of a synthetic US population, in the absence of vaccine availability for children, a targeted approach to rapidly identify silent COVID-19 infections in this age group was estimated to significantly mitigate disease burden. These findings suggest that without measures to interrupt transmission chains from silent infections, vaccination of adults is unlikely to contain the outbreaks in the near term.


Assuntos
Infecções Assintomáticas/epidemiologia , Número Básico de Reprodução/estatística & dados numéricos , Transmissão de Doença Infecciosa , Cobertura Vacinal/estatística & dados numéricos , Vacinação , Adulto , Idoso , /prevenção & controle , /provisão & distribução , Criança , Simulação por Computador , Transmissão de Doença Infecciosa/prevenção & controle , Transmissão de Doença Infecciosa/estatística & dados numéricos , Feminino , Humanos , Recém-Nascido , Masculino , Estados Unidos/epidemiologia , Vacinação/métodos , Vacinação/normas
4.
BMC Res Notes ; 14(1): 132, 2021 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-33845887

RESUMO

OBJECTIVE: Several essential factors have played a crucial role in the spreading mechanism of COVID-19 (Coronavirus disease 2019) in the human population. These factors include undetected cases, asymptomatic cases, and several non-pharmaceutical interventions. Because of the rapid spread of COVID-19 worldwide, understanding the significance of these factors is crucial in determining whether COVID-19 will be eradicated or persist in the population. Hence, in this study, we establish a new mathematical model to predict the spread of COVID-19 considering mentioned factors. RESULTS: Infection detection and vaccination have the potential to eradicate COVID-19 from Jakarta. From the sensitivity analysis, we find that rapid testing is crucial in reducing the basic reproduction number when COVID-19 is endemic in the population rather than contact trace. Furthermore, our results indicate that a vaccination strategy has the potential to relax social distancing rules, while maintaining the basic reproduction number at the minimum possible, and also eradicate COVID-19 from the population with a higher vaccination rate. In conclusion, our model proposed a mathematical model that can be used by Jakarta's government to relax social distancing policy by relying on future COVID-19 vaccine potential.


Assuntos
/administração & dosagem , /prevenção & controle , Programas de Imunização/organização & administração , Número Básico de Reprodução , Humanos , Indonésia/epidemiologia , Modelos Teóricos , Vacinação
5.
Sci Rep ; 11(1): 7342, 2021 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-33795723

RESUMO

We present different data analytic methodologies that have been applied in order to understand the evolution of the first wave of the Coronavirus disease 2019 in the Republic of Cyprus and the effect of different intervention measures that have been taken by the government. Change point detection has been used in order to estimate the number and locations of changes in the behaviour of the collected data. Count time series methods have been employed to provide short term projections and a number of various compartmental models have been fitted to the data providing with long term projections on the pandemic's evolution and allowing for the estimation of the effective reproduction number.


Assuntos
/patologia , Modelos Estatísticos , Número Básico de Reprodução , /virologia , Chipre/epidemiologia , Humanos , Pandemias , /isolamento & purificação
6.
Comput Math Methods Med ; 2021: 6664483, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33815565

RESUMO

In this study, we propose a new mathematical model and analyze it to understand the transmission dynamics of the COVID-19 pandemic in Bangkok, Thailand. It is divided into seven compartmental classes, namely, susceptible (S), exposed (E), symptomatically infected (I s ), asymptomatically infected (I a ), quarantined (Q), recovered (R), and death (D), respectively. The next-generation matrix approach was used to compute the basic reproduction number denoted as R cvd19 of the proposed model. The results show that the disease-free equilibrium is globally asymptotically stable if R cvd19 < 1. On the other hand, the global asymptotic stability of the endemic equilibrium occurs if R cvd19 > 1. The mathematical analysis of the model is supported using numerical simulations. Moreover, the model's analysis and numerical results prove that the consistent use of face masks would go on a long way in reducing the COVID-19 pandemic.


Assuntos
/epidemiologia , Modelos Biológicos , Pandemias/estatística & dados numéricos , Número Básico de Reprodução , Simulação por Computador , Suscetibilidade a Doenças , Humanos , Máscaras , Conceitos Matemáticos , Pandemias/prevenção & controle , Tailândia/epidemiologia
7.
J Biol Dyn ; 15(1): 195-212, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-33827379

RESUMO

Incidence vs. Cumulative Cases (ICC) curves are introduced and shown to provide a simple framework for parameter identification in the case of the most elementary epidemiological model, consisting of susceptible, infected, and removed compartments. This novel methodology is used to estimate the basic reproduction ratio of recent outbreaks, including those associated with the ongoing COVID-19 pandemic.


Assuntos
/epidemiologia , Pandemias/estatística & dados numéricos , Número Básico de Reprodução/estatística & dados numéricos , China/epidemiologia , Simulação por Computador , Suscetibilidade a Doenças , Gastroenterite/epidemiologia , Humanos , Incidência , Conceitos Matemáticos , Modelos Biológicos , Modelos Estatísticos , Dinâmica não Linear , Distribuição de Poisson , Razão Sinal-Ruído , Espanha/epidemiologia
8.
Artigo em Inglês | MEDLINE | ID: mdl-33809958

RESUMO

To curb the spread of SARS-CoV-2 virus (COVID-19) in Malaysia, the government imposed a nationwide movement control order (MCO) from 18 March 2020 to 3 May 2020. It was enforced in four phases (i.e., MCO 1, MCO 2, MCO 3 and MCO 4). In this paper, we propose an initiative to assess the impact of MCO by using time-varying reproduction number (Rt). We used data from the Johns Hopkins University Centre for Systems Science and Engineering Coronavirus repository. Day 1 was taken from the first assumed local transmission of COVID-19. We estimated Rt by using the EpiEstim package and plotted the epidemic curve and Rt. Then, we extracted the mean Rt at day 1, day 5 and day 10 for all MCO phases and compared the differences. The Rt values peaked around day 43, which was shortly before the start of MCO 1. The means for Rt at day 1, day 5, and day 10 for all MCOs ranged between 0.665 and 1.147. The average Rt gradually decreased in MCO 1 and MCO 2. Although spikes in the number of confirmed cases were observed when restrictions were gradually relaxed in the later MCO phases, the situation remained under control with Rt values being stabilised to below unity level (Rt value less than one).


Assuntos
Infecções por Coronavirus , Número Básico de Reprodução , Humanos , Malásia/epidemiologia
9.
Artigo em Inglês | MEDLINE | ID: mdl-33921152

RESUMO

At the beginning of 2020, the global outbreak of the novel coronavirus COVID-19 posed a huge challenge to the governance capabilities of public health in various countries. In this paper, the SEIR model is used to fit the number of confirmed cases in each province in China, and the reduction rate of the basic reproduction number is used to measure the actual score of the control effect of COVID-19. The potential capacity of prevention and control of epidemics, in theory, is constructed, and we use the difference between theoretical ability and actual score to measure the ability of governance of public health. We found that there were significant differences between actual effect and theoretical ability in various regions, and governance capabilities were an important reason leading to this difference, which was not consistent with the level of economic development. The balance of multiple objectives, the guiding ideology of emphasizing medical treatment over prevention, the fragmentation of the public health system, and the insufficiency of prevention and control ability in primary public health systems seriously affected the government's ability to respond to public health emergencies.


Assuntos
Número Básico de Reprodução , China , Humanos , Saúde Pública
10.
Artigo em Inglês | MEDLINE | ID: mdl-33922564

RESUMO

We combine infectious disease transmission and the non-pharmaceutical (NPI) intervention response to disease incidence into one closed model consisting of two coupled delay differential equations for the incidence rate and the time-dependent reproduction number. The model contains three parameters, the initial reproduction number, the intervention strength, and the response delay. The response is modeled by assuming that the rate of change of the reproduction number is proportional to the negative deviation of the incidence rate from an intervention threshold. This delay dynamical system exhibits damped oscillations in one part of the parameter space, and growing oscillations in another, and these are separated by a surface where the solution is a strictly periodic nonlinear oscillation. For the COVID-19 pandemic, the tipping transition from damped to growing oscillations occurs for response delays of about one week, and suggests that, without vaccination, effective control and mitigation of successive epidemic waves cannot be achieved unless NPIs are implemented in a precautionary manner, rather as a response to the present incidence rate. Vaccination increases the quiet intervals between waves, but with delayed response, future flare-ups can only be prevented by establishing a post-pandemic normal with lower basic reproduction number.


Assuntos
Pandemias , Número Básico de Reprodução , Humanos , Incidência
11.
Artigo em Inglês | MEDLINE | ID: mdl-33925665

RESUMO

Detection and isolation of infected people are believed to play an important role in the control of the COVID-19 pandemic. Some countries conduct large-scale screenings for testing, whereas others test mainly people with high prior probability of infection such as showing severe symptoms and/or having an epidemiological link with a known or suspected case or cluster of cases. However, what a good testing strategy is and whether the difference in testing strategy shows a meaningful, measurable impact on the COVID-19 epidemic remain unknown. Here, we showed that patterns of association between effective reproduction number (Rt) and test positivity rate can illuminate differences in testing situation among different areas, using global and local data from Japan. This association can also evaluate the adequacy of current testing systems and what information is captured in COVID-19 surveillance. The differences in testing systems alone cannot predict the results of epidemic containment efforts. Furthermore, monitoring test positivity rates and severe case proportions among the nonelderly can predict imminent case count increases. Monitoring test positivity rates in conjunction with the concurrent Rt could be useful to assess and strengthen public health management and testing systems and deepen understanding of COVID-19 epidemic dynamics.


Assuntos
Número Básico de Reprodução , Humanos , Japão/epidemiologia , Pandemias
12.
BMC Infect Dis ; 21(1): 274, 2021 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-33736606

RESUMO

BACKGROUND: In 2010-2011, we conducted a social contact survey in Flanders, Belgium, aimed at improving and extending the design of the first social contact survey conducted in Belgium in 2006. This second social contact survey aimed to enable, for the first time, the estimation of social mixing patterns for an age range of 0 to 99 years and the investigation of whether contact rates remain stable over this 5-year time period. METHODS: Different data mining techniques are used to explore the data, and the age-specific number of social contacts and the age-specific contact rates are modelled using a generalized additive models for location, scale and shape (GAMLSS) model. We compare different matrices using assortativeness measures. The relative change in the basic reproduction number (R0) and the ratio of relative incidences with 95% bootstrap confidence intervals (BCI) are employed to investigate and quantify the impact on epidemic spread due to differences in sex, day of the week, holiday vs. regular periods and changes in mixing patterns over the 5-year time gap between the 2006 and 2010-2011 surveys. Finally, we compare the fit of the contact matrices in 2006 and 2010-2011 to Varicella serological data. RESULTS: All estimated contact patterns featured strong homophily in age and sex, especially for small children and adolescents. A 30% (95% BCI [17%; 37%]) and 29% (95% BCI [14%; 40%]) reduction in R0 was observed for weekend versus weekdays and for holiday versus regular periods, respectively. Significantly more interactions between people aged 60+ years and their grandchildren were observed on holiday and weekend days than on regular weekdays. Comparing contact patterns using different methods did not show any substantial differences over the 5-year time period under study. CONCLUSIONS: The second social contact survey in Flanders, Belgium, endorses the findings of its 2006 predecessor and adds important information on the social mixing patterns of people older than 60 years of age. Based on this analysis, the mixing patterns of people older than 60 years exhibit considerable heterogeneity, and overall, the comparison of the two surveys shows that social contact rates can be assumed stable in Flanders over a time span of 5 years.


Assuntos
Número Básico de Reprodução , Epidemias , Rede Social , Inquéritos e Questionários , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Bélgica/epidemiologia , Varicela/epidemiologia , Criança , Pré-Escolar , Busca de Comunicante , Família , Feminino , Férias e Feriados , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Adulto Jovem
13.
Elife ; 102021 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-33722343

RESUMO

Analysing the characteristics of the SARS-CoV-2 virus makes it possible to estimate the length of quarantine that reduces the impact on society and the economy, while minimising infections.


Assuntos
Quarentena , Número Básico de Reprodução , Busca de Comunicante , Humanos
14.
BMC Infect Dis ; 21(1): 245, 2021 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-33676420

RESUMO

BACKGROUND: Based on differences in populations and prevention and control measures, the spread of new coronary pneumonia in different countries and regions also differs. This study aimed to calculate the transmissibility of coronavirus disease 2019 (COVID-19), and to evaluate the effectiveness of measures to control the disease in Jilin Province, China. METHODS: The data of reported COVID-19 cases were collected, including imported and local cases from Jilin Province as of March 14, 2019. A Susceptible-Exposed-Infectious-Asymptomatic-Recovered/Removed (SEIAR) model was developed to fit the data, and the effective reproduction number (Reff) was calculated at different stages in the province. Finally, the effectiveness of the measures was assessed. RESULTS: A total of 97 COVID-19 infections were reported in Jilin Province, among which 45 were imported infections (including one asymptomatic infection) and 52 were local infections (including three asymptomatic infections). The model fit the reported data well (R2 = 0.593, P < 0.001). The Reff of COVID-19 before and after February 1, 2020 was 1.64 and 0.05, respectively. Without the intervention taken on February 1, 2020, the predicted cases would have reached a peak of 177,011 on October 22, 2020 (284 days from the first case). The projected number of cases until the end of the outbreak (on October 9, 2021) would have been 17,129,367, with a total attack rate of 63.66%. Based on the comparison between the predicted incidence of the model and the actual incidence, the comprehensive intervention measures implemented in Jilin Province on February 1 reduced the incidence of cases by 99.99%. Therefore, according to the current measures and implementation efforts, Jilin Province can achieve good control of the virus's spread. CONCLUSIONS: COVID-19 has a moderate transmissibility in Jilin Province, China. The interventions implemented in the province had proven effective; increasing social distancing and a rapid response by the prevention and control system will help control the spread of the disease.


Assuntos
Número Básico de Reprodução , Controle de Doenças Transmissíveis , Avaliação de Resultados em Cuidados de Saúde/estatística & dados numéricos , /epidemiologia , /transmissão , China/epidemiologia , Controle de Doenças Transmissíveis/métodos , Controle de Doenças Transmissíveis/organização & administração , Controle de Doenças Transmissíveis/normas , Humanos , Incidência , /isolamento & purificação
15.
Infez Med ; 29(1): 10-19, 2021 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-33664169

RESUMO

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a pandemic worldwide. On a daily basis the number of deaths associated with COVID-19 is rapidly increasing. The main transmission route of SARS-CoV-2 is through the air (airborne transmission). This review details the airborne transmission of SARS-CoV-2, the aerodynamics, and different modes of transmission (e.g. droplets, droplet nuclei, and aerosol particles). SARS-CoV-2 can be transmitted by an infected person during activities such as expiration, coughing, sneezing, and talking. During such activities and some medical procedures, aerosols and droplets contaminated with SARS-CoV-2 particles are formed. Depending on their sizes and the environmental conditions, such particles stay viable in the air for varying time periods and can cause infection in a susceptible host. Very few studies have been conducted to establish the mechanism or the aerodynamics of virus-loaded particles and droplets in causing infection. In this review we discuss the various forms in which SARS-CoV-2 virus particles can be transmitted in air and cause infections.


Assuntos
Microbiologia do Ar , /transmissão , Número Básico de Reprodução/estatística & dados numéricos , Tosse/virologia , Exposição Ambiental , Humanos , Máscaras , Espirro
16.
J Med Internet Res ; 23(4): e24389, 2021 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-33755577

RESUMO

BACKGROUND: The dynamics of the COVID-19 pandemic vary owing to local population density and policy measures. During decision-making, policymakers consider an estimate of the effective reproduction number Rt, which is the expected number of secondary infections spread by a single infected individual. OBJECTIVE: We propose a simple method for estimating the time-varying infection rate and the Rt. METHODS: We used a sliding window approach with a Susceptible-Infectious-Removed (SIR) model. We estimated the infection rate from the reported cases over a 7-day window to obtain a continuous estimation of Rt. A proposed adaptive SIR (aSIR) model was applied to analyze the data at the state and county levels. RESULTS: The aSIR model showed an excellent fit for the number of reported COVID-19 cases, and the 1-day forecast mean absolute prediction error was <2.6% across all states. However, the 7-day forecast mean absolute prediction error approached 16.2% and strongly overestimated the number of cases when the Rt was rapidly decreasing. The maximal Rt displayed a wide range of 2.0 to 4.5 across all states, with the highest values for New York (4.4) and Michigan (4.5). We found that the aSIR model can rapidly adapt to an increase in the number of tests and an associated increase in the reported cases of infection. Our results also suggest that intensive testing may be an effective method of reducing Rt. CONCLUSIONS: The aSIR model provides a simple and accurate computational tool for continuous Rt estimation and evaluation of the efficacy of mitigation measures.


Assuntos
Número Básico de Reprodução , Modelos Teóricos , Previsões , Humanos , Estados Unidos
17.
Comput Math Methods Med ; 2021: 6647425, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33777169

RESUMO

A modeling approach to investigate the dynamics of COVID-19 epidemics coupled with fear is presented in this paper. The basic reproduction number R 0 is computed and employed in analysing the effect of initial transmission and the conditions for disease control or eradication. Numerical simulations show that whenever there is an outbreak coupled with fear, the disease is likely to persist in the first two months, and after that, it will start to slow down as the recovery rate from fear increases. An increase in the number of recovered individuals lead to a rise in the number of susceptibles and consequently set off a second wave of infection in the third month of the epidemic.


Assuntos
/epidemiologia , Epidemias , Medo , Algoritmos , Número Básico de Reprodução , Simulação por Computador , Surtos de Doenças , Humanos , Controle de Infecções , Modelos Teóricos , Pandemias
18.
PLoS Comput Biol ; 17(3): e1008892, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33780436

RESUMO

The SARS-CoV-2 pathogen is currently spreading worldwide and its propensity for presymptomatic and asymptomatic transmission makes it difficult to control. The control measures adopted in several countries aim at isolating individuals once diagnosed, limiting their social interactions and consequently their transmission probability. These interventions, which have a strong impact on the disease dynamics, can affect the inference of the epidemiological quantities. We first present a theoretical explanation of the effect caused by non-pharmaceutical intervention measures on the mean serial and generation intervals. Then, in a simulation study, we vary the assumed efficacy of control measures and quantify the effect on the mean and variance of realized generation and serial intervals. The simulation results show that the realized serial and generation intervals both depend on control measures and their values contract according to the efficacy of the intervention strategies. Interestingly, the mean serial interval differs from the mean generation interval. The deviation between these two values depends on two factors. First, the number of undiagnosed infectious individuals. Second, the relationship between infectiousness, symptom onset and timing of isolation. Similarly, the standard deviations of realized serial and generation intervals do not coincide, with the former shorter than the latter on average. The findings of this study are directly relevant to estimates performed for the current COVID-19 pandemic. In particular, the effective reproduction number is often inferred using both daily incidence data and the generation interval. Failing to account for either contraction or mis-specification by using the serial interval could lead to biased estimates of the effective reproduction number. Consequently, this might affect the choices made by decision makers when deciding which control measures to apply based on the value of the quantity thereof.


Assuntos
/epidemiologia , Modelos Estatísticos , Pandemias/prevenção & controle , Infecções Assintomáticas/epidemiologia , Número Básico de Reprodução/estatística & dados numéricos , Biologia Computacional , Simulação por Computador , Humanos , Incidência , Prevalência , Processos Estocásticos , Fatores de Tempo
19.
Artigo em Inglês | MEDLINE | ID: mdl-33668472

RESUMO

The emergence and spread of vector-borne diseases (VBDs) is a function of biotic, abiotic and socio-economic drivers of disease while their economic and societal burden depends upon a number of time-varying factors. This work is concerned with the development of an early warning system that can act as a predictive tool for public health preparedness and response. We employ a host-vector model that combines entomological (mosquito data), social (immigration rate, demographic data), environmental (temperature) and geographical data (risk areas). The output consists of appropriate maps depicting suitable risk measures such as the basic reproduction number, R0, and the probability of getting infected by the disease. These tools consist of the backbone of a semi-automatic early warning system tool which can potentially aid the monitoring and control of VBDs in different settings. In addition, it can be used for optimizing the cost-effectiveness of distinct control measures and the integration of open geospatial and climatological data. The R code used to generate the risk indicators and the corresponding spatial maps along with the data is made available.


Assuntos
Mosquitos Vetores , Doenças Transmitidas por Vetores , Animais , Número Básico de Reprodução , Vetores de Doenças , Fatores de Risco
20.
Science ; 372(6538)2021 04 09.
Artigo em Inglês | MEDLINE | ID: mdl-33658326

RESUMO

A severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant, VOC 202012/01 (lineage B.1.1.7), emerged in southeast England in September 2020 and is rapidly spreading toward fixation. Using a variety of statistical and dynamic modeling approaches, we estimate that this variant has a 43 to 90% (range of 95% credible intervals, 38 to 130%) higher reproduction number than preexisting variants. A fitted two-strain dynamic transmission model shows that VOC 202012/01 will lead to large resurgences of COVID-19 cases. Without stringent control measures, including limited closure of educational institutions and a greatly accelerated vaccine rollout, COVID-19 hospitalizations and deaths across England in the first 6 months of 2021 were projected to exceed those in 2020. VOC 202012/01 has spread globally and exhibits a similar transmission increase (59 to 74%) in Denmark, Switzerland, and the United States.


Assuntos
/transmissão , /virologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Número Básico de Reprodução , /mortalidade , Criança , Pré-Escolar , Controle de Doenças Transmissíveis , Inglaterra/epidemiologia , Europa (Continente)/epidemiologia , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Modelos Teóricos , Mutação , /crescimento & desenvolvimento , Índice de Gravidade de Doença , Fatores Socioeconômicos , Estados Unidos/epidemiologia , Carga Viral , Adulto Jovem
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