scholarly journals Comparative evaluation of the transmissibility of SARS-CoV-2 variants of concern

2021 ◽  
Author(s):  
Liang Wang ◽  
Xavier Didelot ◽  
Yuhai Bi ◽  
George Fu Gao
Keyword(s):  
Comparative Evaluation ◽  
Prevention And Control ◽  
Large Scale ◽  
Reproduction Number ◽  
Genomic Data ◽  
Control Measures ◽  
Global Pandemic ◽  
Time Period ◽  
Exact Reproduction ◽  
And Control

Since the start of the SARS-CoV-2 pandemic in late 2019, several variants of concern (VOC) have been reported, such as B.1.1.7, B.1.351, P.1, and B.1.617.2. The exact reproduction number Rt for these VOCs is important to determine appropriate control measures. Here, we estimated the transmissibility for VOCs and lineages of SAR-CoV-2 based on genomic data and Bayesian inference under an epidemiological model to infer the reproduction number (Rt). We analyzed data for multiple VOCs from the same time period and countries, in order to compare their transmissibility while controlling for geographical and temporal factors. The lineage B had a significantly higher transmissibility than lineage A, and contributed to the global pandemic to a large extent. In addition, all VOCs had increased transmissibility when compared with other lineages in each country, indicating they are harder to control and present a high risk to public health. All countries should formulate specific prevention and control policies for these VOCs when they are detected to curve their potential for large-scale spread.

scholarly journals Heterogeneity and effectiveness analysis of COVID-19 prevention and control in major cities in China through time-varying reproduction number estimation

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Qing Cheng ◽  
Zeyi Liu ◽  
Guangquan Cheng ◽  
Jincai Huang
Keyword(s):  
Prevention And Control ◽  
Large Scale ◽  
Reproduction Number ◽  
Correlation Method ◽  
Control Measures ◽  
Time Varying ◽  
Short Period ◽  
Significant Difference ◽  
Prevention And Control Measures ◽  
And Control

AbstractBeginning on December 31, 2019, the large-scale novel coronavirus disease 2019 (COVID-19) emerged in China. Tracking and analysing the heterogeneity and effectiveness of cities’ prevention and control of the COVID-19 epidemic is essential to design and adjust epidemic prevention and control measures. The number of newly confirmed cases in 25 of China’s most-affected cities for the COVID-19 epidemic from January 11 to February 10 was collected. The heterogeneity and effectiveness of these 25 cities’ prevention and control measures for COVID-19 were analysed by using an estimated time-varying reproduction number method and a serial correlation method. The results showed that the effective reproduction number (R) in 25 cities showed a downward trend overall, but there was a significant difference in the R change trends among cities, indicating that there was heterogeneity in the spread and control of COVID-19 in cities. Moreover, the COVID-19 control in 21 of 25 cities was effective, and the risk of infection decreased because their R had dropped below 1 by February 10, 2020. In contrast, the cities of Wuhan, Tianmen, Ezhou and Enshi still had difficulty effectively controlling the COVID-19 epidemic in a short period of time because their R was greater than 1.

scholarly journals The spatial transmission of SARS-CoV-2 in China under the prevention and control measures at the early outbreak

2021 ◽  
Vol 79 (1) ◽  
Author(s):  
Jianli Liu ◽  
Yuan Zhou ◽  
Chuanyu Ye ◽  
Guangming Zhang ◽  
Feng Zhang ◽  
...  
Keyword(s):  
Basic Reproduction Number ◽  
Prevention And Control ◽  
Reproduction Number ◽  
Early Stage ◽  
Chinese Mainland ◽  
Hubei Province ◽  
Control Measures ◽  
Provincial Level ◽  
Prevention And Control Measures ◽  
And Control

Abstract Background Since severe acute respiratory syndrome coronavirus, 2 (SARS-CoV-2) was firstly reported in Wuhan City, China in December 2019, Novel Coronavirus Disease 2019 (COVID-19) that is caused by SARS-CoV-2 is predominantly spread from person-to-person on worldwide scales. Now, COVID-19 is a non-traditional and major public health issue the world is facing, and the outbreak is a global pandemic. The strict prevention and control measures have mitigated the spread of SARS-CoV-2 and shown positive changes with important progress in China. But prevention and control tasks remain arduous for the world. The objective of this study is to discuss the difference of spatial transmission characteristics of COVID-19 in China at the early outbreak stage with resolute efforts. Simultaneously, the COVID-19 trend of China at the early time was described from the statistical perspective using a mathematical model to evaluate the effectiveness of the prevention and control measures. Methods In this study, the accumulated number of confirmed cases publicly reported by the National Health Committee of the People’s Republic of China (CNHC) from January 20 to February 11, 2020, were grouped into three partly overlapping regions: Chinese mainland including Hubei province, Hubei province alone, and the other 30 provincial-level regions on Chinese mainland excluding Hubei province, respectively. A generalized-growth model (GGM) was used to estimate the basic reproduction number to evaluate the transmissibility in different spatial locations. The prevention and control of COVID-19 in the early stage were analyzed based on the number of new cases of confirmed infections daily reported. Results Results indicated that the accumulated number of confirmed cases reported from January 20 to February 11, 2020, is well described by the GGM model with a larger correlation coefficient than 0.99. When the accumulated number of confirmed cases is well fitted by an exponential function, the basic reproduction number of COVID-19 of the 31 provincial-level regions on the Chinese mainland, Hubei province, and the other 30 provincial-level regions on the Chinese mainland excluding Hubei province, is 2.68, 6.46 and 2.18, respectively. The consecutive decline of the new confirmed cases indicated that the prevention and control measures taken by the Chinese government have contained the spread of SARS-CoV-2 in a short period. Conclusions The estimated basic reproduction number thorough GGM model can reflect the spatial difference of SARS-CoV-2 transmission in China at the early stage. The strict prevention and control measures of SARS-CoV-2 taken at the early outbreak can effectively reduce the new confirmed cases outside Hubei and have mitigated the spread and yielded positive results since February 2, 2020. The research results indicated that the outbreak of COVID-19 in China was sustaining localized at the early outbreak stage and has been gradually curbed by China’s resolute efforts.

scholarly journals Heterogeneity and effectiveness analysis of COVID-19 prevention and control in major cities in China through time-varying reproduction numbers estimation

2020 ◽  
Author(s):  
Qing Cheng ◽  
Zeyi Liu ◽  
Guangquan Cheng ◽  
Jincai Huang
Keyword(s):  
Prevention And Control ◽  
Large Scale ◽  
Correlation Method ◽  
Control Measures ◽  
Time Varying ◽  
Reproduction Numbers ◽  
Short Period ◽  
Significant Difference ◽  
Novel Coronavirus ◽  
And Control

Abstract From December 31, 2019, a large-scale 2019 novel coronavirus disease (COVID-19) broke out in China. Tracking and analyzing the heterogeneity and effectiveness of cities’ prevention and control for COVID-19 epidemic is essential to design and adjust epidemic prevention and control. The number of newly infected cases in 25 China’s worst cities for COVID-19 epidemic from January 11 to February 10 was collected. The heterogeneity and effectiveness of these 25 cities’ prevention and control measures for COVID-19 were analyzed by using a estimate time-varying reproduction numbers method and a serial correlation method. The results shown that the effective reproduction number (R) in 25 cities showed a downward trend as a whole, but there was a significant difference in the R change trends among cities indicating that there was heterogeneity in the spread and control of COVID-19 in cities. Moreover, the COVID-19 control in 21 of 25 cities were effective and the risk of infection was decreasing due to their R had dropped below 1 on February 10, 2020 and the average decline of R in the past 5 days was greater than 0, while cities of Wuhan, Tianmen, Ezhou and Enshi were still difficult to effectively control the COVID-19 epidemic in a short period of time because their R was also greater than 1.

scholarly journals Shortages of hospital beds exacerbate severity of COVID-19 outbreaks

2020 ◽  
Author(s):  
Weike Zhou ◽  
Aili Wang ◽  
Xia Wang ◽  
Robert A Cheke ◽  
Sanyi Tang
Keyword(s):  
Prevention And Control ◽  
Reproduction Number ◽  
Control Strategies ◽  
Threshold Value ◽  
Control Measures ◽  
Unknown Parameters ◽  
Health Authorities ◽  
Hospital Beds ◽  
And Control ◽  
The Impact

Abstract Background: The global outbreak of COVID-19 has caused worrying concern amongst the public and health authorities. The first and foremost problem that many countries face is a shortage of medical resources. The experience of Wuhan, China, in fighting against COVID-19 provides a model for other countries to learn from. Methods: We formulated a piecewise smooth model to describe the limitation of hospital beds, based on the transmission progression of COVID-19, and the strengthening prevention and control strategies implemented in Wuhan, China. We used data of the cumulative numbers of confirmed cases, cured cases and deaths in Wuhan city from 10 January to 20 March, 2020 to estimate unknown parameters and the effective reproduction number. Sensitivity analysis was conducted to investigate the impact of a shortage of hospital beds on the COVID-19 outbreak. Results: Even with strong prevention and control measures in Wuhan, slowing down of the supply rate, reducing the maximum capacity and delaying the intervention time of supplementing hospital beds aggravated the outbreak severity by magnifying the cumulative numbers of confirmed cases and deaths, prolonging the period of the outbreak in Wuhan, enlarging the value of the effective reproduction number during the outbreak and postponing the time when the threshold value is reduced to 1. Conclusions: The quick establishment of the Huoshenshan and Leishenshan Hospitals in a short time and the deployment of mobile cabin hospitals played important roles in containing the COVID-19 outbreak in Wuhan, providing a model for other countries to provide more hospital beds for COVID-19 patients faster and earlier.

scholarly journals What matters: non-pharmaceutical interventions for COVID-19 in Europe

2022 ◽  
Vol 11 (1) ◽  
Author(s):  
Yan Liu ◽  
Qiuyan Yu ◽  
Haoyu Wen ◽  
Fang Shi ◽  
Fang Wang ◽  
...  
Keyword(s):  
Prevention And Control ◽  
Large Scale ◽  
Great Influence ◽  
Control Measures ◽  
European Countries ◽  
World Health ◽  
Current Status ◽  
Key Factors ◽  
Prevention And Control Measures ◽  
And Control

Abstract Objectives The purpose of this study is to describe the situation of COVID-19 in European countries and to identify important factors related to prevention and control. Methods We obtained data from World Health Statistics 2020 and the Institute for Health Metrics and Evaluation (IHME). We calculated the Rt values of 51 countries in Europe under different prevention and control measures. We used lasso regression to screen factors associated with morbidity and mortality. For the selected variables, we used quantile regression to analyse the relevant influencing factors in countries with different levels of morbidity or mortality. Results The government has a great influence on the change in Rt value through prevention and control measures. The most important factors for personal and group prevention and control are the mobility index, testing, the closure of educational facilities, restrictions on large-scale gatherings, and commercial restrictions. The number of ICU beds and doctors in medical resources are also key factors. Basic sanitation facilities, such as the proportion of safe drinking water, also have an impact on the COVID-19 epidemic. Conclusions We described the current status of COVID-19 in European countries. Our findings demonstrated key factors in individual and group prevention measures.

scholarly journals What Matters among Non-pharmaceutical Interventions on COVID-19 in Europe?

2021 ◽  
Author(s):  
Chuanhua Yu ◽  
Yan Liu ◽  
Qiuyan Yu ◽  
Haoyu Wen ◽  
Fang Shi ◽  
...  
Keyword(s):  
Prevention And Control ◽  
Large Scale ◽  
Great Influence ◽  
Control Measures ◽  
European Countries ◽  
World Health ◽  
Current Status ◽  
Key Factors ◽  
Prevention And Control Measures ◽  
And Control

Abstract Objectives The purpose of this study is to describe the situation of the COVID-19 in European countries and identify important factors related to prevention and control. Methods We obtained data from World Health Statistics 2020 and the Institute for Health Metrics and Evaluation (IHME). We caculated the Rt values of 51countries in Europe under different prevention and control measures. We used lasso regression to screen factors associated with morbidity and mortality. For variables selected, we used quantile regression to analyze the relevant influencing factors in countries with different levels of morbidity or mortality. Results The government has a great influence on the change of Rt value through prevention and control measures. The most important factor for personal and group prevention and control is the mobility index, testing, the closure of educational facilities, restrictions on large-scale gatherings, and commercial restrictions. The number of ICU beds and doctors in medical resources are also key factors. Basic sanitation facilities, such as the proportion of safe drinking water, also have an impact on the COVID-19 epidemic. Conclusions This study describes the current status of COVID-19 in European countries. We found key factors in individual prevention and control measures and group prevention and control measures.

scholarly journals Transmission of COVID-19 in the state of Georgia, United States: Spatiotemporal variation and impact of social distancing

2020 ◽  
Author(s):  
Yuke Wang ◽  
Casey Siesel ◽  
Yangping Chen ◽  
Ben Lopman ◽  
Laura Edison ◽  
...  
Keyword(s):  
United States ◽  
Prevention And Control ◽  
Reproduction Number ◽  
The State ◽  
County Level ◽  
Time Period ◽  
Serial Interval ◽  
June July ◽  
And Control ◽  
Over Time

SummaryBackgroundBeginning in early February 2020, COVID-19 spread across the state of Georgia, leading to 258,354 cumulative cases as of August 25, 2020. The time scale of spreading (i.e., serial interval) and magnitude of spreading (i.e., Rt or reproduction number) for COVID-19, were observed to be heterogenous by demographic characteristics, region and time period. In this study, we examined the COVID-19 transmission in the state of Georgia, United States.MethodsDuring February 1 to July 13, 2020, we identified 4080 transmission pairs using contact information from reports of COVID-19 cases from the Georgia Department of Public Health. We examined how various transmission characteristics were affected by disease symptoms, demographics (age, gender, and race), and time period (during shelter-in-place and after reopening). In addition, we estimated the time course of reproduction numbers during early February–mid-June for all 159 counties in the state of Georgia, using a total of 118,491 reported COVID-19 cases.FindingsOver this period, the serial interval appeared to decrease from 5.97 days in February–April to 4.40 days in June–July. With regard to age, transmission was assortative and patterns of transmission changed over time. COVID-19 mainly spread from adults to all age groups; transmission among and between children and the elderly was found less frequently. Younger adults (20– 50 years old) were involved in the majority of transmissions occurring during or after reopening subsequent to the shelter-in-place period. By mid-July, two waves of COVID-19 transmission were apparent, separated by the shelter-in-place period in the state of Georgia. Counties around major cities and along interstate highways had more intense transmission.InterpretationThe transmission of COVID-19 in the state of Georgia had been heterogeneous by area and changed over time. The shelter-in-place was not long enough to sufficiently suppress COVID-19 transmission in densely populated urban areas connected by major transportation links. Studying local transmission patterns may help in predicting and guiding states in prevention and control of COVID-19 according to population and region.FundingEmory COVID-19 Response Collaborative.Research in contextEvidence before this studyThe ongoing COVID-19 pandemic has caused 37,109,581 cases and 1,070,355 deaths worldwide as of October 11, 2020. We searched PubMed for articles published on and before October 11, 2020 using keywords “novel coronavirus”, “SARS–nCoV–2”, “COVID-19”, “transmission”, “serial interval”, “reproduction number”, and “shelter-in-place”. Few published studies have estimated the serial interval but no study was found that examined the time-varying serial interval. Few studies have examined the transmission patterns between groups with different characteristics. And no study has examined the timevarying reproduction number for COVID-19 and impact of shelter-in-place order at the county level in the United States.Added value of this studyTo our knowledge, this is the first study showing the multiple aspects of COVID-19 transmission, including serial interval, transmission patterns between age, gender, or race groups, and spatiotemporal patterns, based on data from 118,491 confirmed COVID-19 cases and 4080 tracked pairs of infector and infectee. We found that during February–July the serial interval for symptom onset shortened, and the major contribution to the spread of COVID-19 shifted to younger ages (from 40–70 years old in February–April to 20–50 years old in June–July). We also found three to four weeks of the shelter-in-place slowed transmission but was insufficient to prevent transmission into urban and peri-urban counties connected with major transportation.Implications of all the available evidenceThe contracting serial intervals and increasing spread by younger generation show the COVID-19 transmission at county level changes over time. The spatiotemporal patterns of transmission in county level further provide important evidence to guide effective COVID-19 prevention and control measures (e.g., shelter-in-place) in different areas.

scholarly journals A deterministic epidemic model for the emergence of COVID-19 in China

2020 ◽  
Author(s):  
Meng Wang ◽  
Jingtao Qi
Keyword(s):  
Prevention And Control ◽  
Reproduction Number ◽  
Chinese Mainland ◽  
Hubei Province ◽  
Control Measures ◽  
The Novel ◽  
Health Authorities ◽  
Prevention And Control Measures ◽  
Novel Coronavirus ◽  
And Control

AbstractCoronavirus disease (COVID-19) broke out in Wuhan, Hubei province, China, in December 2019 and soon after Chinese health authorities took unprecedented prevention and control measures to curb the spreading of the novel coronavirus-related pneumonia. We develop a mathematical model based on daily updates of reported cases to study the evolution of the epidemic. With the model, on 95% confidence level, we estimate the basic reproduction number, R0 = 2.82 ± 0.11, time between March 19 and March 21 when the effective reproduction number becoming less than one, the epidemic ending after April 2 and the total number of confirmed cases approaching 14408 ± 429 on the Chinese mainland excluding Hubei province.

Knowledge and Awareness of Dengue Fever

2018 ◽  
pp. 219-222
Author(s):  
Y. Arockia Suganthi ◽  
Chitra K. ◽  
J. Magelin Mary
Keyword(s):  
Dengue Fever ◽  
Prevention And Control ◽  
Control Measures ◽  
Infection Transmission ◽  
Standard Guideline ◽  
The World ◽  
Different Types ◽  
Prevention And Control Measures ◽  
Dengue Prevention ◽  
And Control

Dengue fever is a painful mosquito-borne infection caused by different types of virus in various localities of the world. There is no particular medicine or vaccine to treat person suffering from dengue fever. Dengue viruses are transmitted by the bite of female Aedes (Ae) mosquitoes. Dengue fever viruses are mainly transmitted by Aedes which can be active in tropical or subtropical climates. Aedes Aegypti is the key step to avoid infection transmission to save millions of people in all over the world. This paper provides a standard guideline in the planning of dengue prevention and control measures. At the same time gives the priorities including clinical management and hospitalized dengue patients have to address essentially.

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