4.Evaluation of the effect of varicella outbreak control measures through a discrete time delay SEIR model.
Jin-ren PAN ; Zheng-qiang HUANG ; Kun CHEN
Chinese Journal of Preventive Medicine 2012;46(4):343-347
OBJECTIVEforecast the epidemic trend and to evaluate the effect of outbreak control measures by investigation of a varicella outbreak event with a discrete time delay SEIR model.
METHODSA discrete time delay model was formulated by discretization method based on a continuous SEIR model with the consideration of the time delay effect on latent period and communicable period. The epidemic trend forecast was carried out based on the number of expected cases. The theoretical effect evaluation was assessed by comparing the results from different emergency control measures.
RESULTSWithout any control measures, the theoretical attack rate was 30.16% (504/1671). The course of the epidemic lasted for 4 months and the peak epidemic time was 78 days after the onset of the first case. 'Generation' phenomenon had been observed in the course of the epidemic with the interval of two weeks. The actual number of cases was decreased by 89.48% (451/504) compared with the number of expected cases under no control measure scenario. With the rigorous quarantine measure for all cases on their onset day, when the measure was conducted on 0, 14, 28, 42 days after the onset of the first case, the total numbers of expected cases were 22, 59, 127 and 220 respectively. With the quarantine measure conducted on 14 days after the onset of the first case, when the proportion of quarantine was 30%, 50%, 70%, 90%, the total number of expected cases were 485, 457, 386 and 169, respectively. With the emergent vaccination for all persons, when the measure was conducted on 0, 14, 28, 42 days after the onset of the first case, the total numbers of expected cases were 7, 26, 81 and 202 respectively. With the emergent vaccination conducted on 14 days after the onset of the first case, when the immunization coverage rate was 30%, 50%, 70%, 90%, the total numbers of expected cases were 354, 246, 127 and 40, respectively.
CONCLUSIONThe number of expected cases can be regarded as the reference to evaluate the effect of control measures. The simulation results suggest that it will get more benefits to conduct control measures earlier in varicella outbreak events, and the effect of emergent vaccination is better than that of quarantine measure under the same conditions.
Chickenpox ; epidemiology ; prevention & control ; Communicable Disease Control ; methods ; Disease Outbreaks ; prevention & control ; Humans ; Incidence ; Models, Theoretical
5.2022 Multiple-country Monkeypox Outbreak and Its Importation Risk into China: An Assessment Based on the Risk Matrix Method.
Min DU ; Shi Mo ZHANG ; Wei Jing SHANG ; Wen Xin YAN ; Qiao LIU ; Chen Yuan QIN ; Min LIU ; Jue LIU
Biomedical and Environmental Sciences 2022;35(10):878-887
OBJECTIVE:
To analyze the 2022 multiple-country monkeypox outbreak and assess its importation risk into China.
METHODS:
Data was from United States Centers for Disease Control and Prevention. We described the global epidemic and calculated concentration index to measure economic-related inequality. Importation risk into China was evaluated and ranked by using risk matrix method and Borda count method, respectively.
RESULTS:
As of July 29, 2022, of 79 countries or territories, 39 (49.37%, 39/79), 17 (21.52%, 17/79), 6 (7.59%, 6/79), 12 (15.19%, 12/79), and 5 (6.33%, 5/79) country or territories identified cases < 10, 10-, 51-, 101-, and > 1,000. There were economic-related health disparities exist in the distribution of cases (the concentration index = 0.42, P = 0.027), and the inequality disadvantageous to the rich (pro-poor). There were 12 (15.38%, 12/78), 15 (19.23%, 15/78), 6 (7.69%, 6/78), and 45 (57.69%, 45/78) countries or territories with extremely high, high, moderate, and low importation risk. United States and France ranked first with the highest Borda points of 156, and counts of zero.
CONCLUSION
Of 78 countries or territories, the key attention need be paid to the United States and France, relatively. As the epidemic progresses, preparing prevention and control measures to further reduce importation risk was crucial.
Humans
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China/epidemiology*
;
Disease Outbreaks/prevention & control*
;
France
;
Monkeypox/prevention & control*
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Risk Assessment
6.Unusual global outbreak of monkeypox: what should we do?
Miaojin ZHU ; Jia JI ; Danrong SHI ; Xiangyun LU ; Baohong WANG ; Nanping WU ; Jie WU ; Hangping YAO ; Lanjuan LI
Frontiers of Medicine 2022;16(4):507-517
Recently, monkeypox has become a global concern amid the ongoing COVID-19 pandemic. Monkeypox is an acute rash zoonosis caused by the monkeypox virus, which was previously concentrated in Africa. The re-emergence of this pathogen seems unusual on account of outbreaks in multiple nonendemic countries and the incline to spread from person to person. We need to revisit this virus to prevent the epidemic from getting worse. In this review, we comprehensively summarize studies on monkeypox, including its epidemiology, biological characteristics, pathogenesis, and clinical characteristics, as well as therapeutics and vaccines, highlighting its unusual outbreak attributed to the transformation of transmission. We also analyze the present situation and put forward countermeasures from both clinical and scientific research to address it.
COVID-19
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Disease Outbreaks/prevention & control*
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Humans
;
Monkeypox/epidemiology*
;
Monkeypox virus
;
Pandemics/prevention & control*
7.Advance on research and application of laboratory pathogen monitoring and early warning technology of bacterial infectious diseases.
Chinese Journal of Preventive Medicine 2022;56(4):525-532
Human beings are still facing the public health challenges from bacterial infectious diseases. Carrying out systematic infectious disease monitoring and early warning is the most direct solution to prevent and control infectious diseases. Etiology is an important part of infectious disease monitoring and early warning. Effective pathogen monitoring can identify pathogens, outbreaks and sources at the first time. In this study, we have reviewed the research and application of etiology monitoring and early warning technology of bacterial infectious diseases and summarized the importance and application scenarios of etiology in infectious disease monitoring and early warning, as well as the research progress of etiology monitoring and early warning technology. Based on the work of existing laboratory monitoring networks, such as Chinese Pathogen Identification Network, the development trend and prospect of infectious disease laboratory network monitoring are put forward to provide a reference for establishing and perfecting the infectious disease monitoring and early warning system.
Bacterial Infections/prevention & control*
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Communicable Diseases/epidemiology*
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Disease Outbreaks/prevention & control*
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Humans
;
Laboratories
;
Technology
8.Progress in the practice of surveillance and early warning of infectious diseases in major countries and regions.
Shuo HUANG ; Cai Xiong LIU ; Yuan DENG ; Cui Hong ZHANG ; Si Meng FAN ; Jian Dong ZHENG ; Li Ping WANG
Chinese Journal of Epidemiology 2022;43(4):591-597
The COVID-19 pandemic is yet another reminder that the threat of infectious disease has never really gone away. As the cornerstone of preventing and controlling infectious diseases, effective surveillance and early warning are of great significance in understanding the outbreak and epidemic of specific infectious diseases and putting forward effective prevention and control measures. Therefore, we must continue strengthening the construction of infectious disease surveillance and early warning system. We reviewed the surveillance and early warning practices of infectious diseases in major countries and regions, then discussed the development direction in the field of surveillance and early warning of infectious diseases to provide the reference for strengthening the construction and capacity of infectious disease surveillance and early warning system in China.
COVID-19
;
China/epidemiology*
;
Communicable Diseases/epidemiology*
;
Disease Outbreaks/prevention & control*
;
Humans
;
Pandemics/prevention & control*
9.Strategy and measures in response to highly uncertain emerging infectious disease.
Chinese Journal of Epidemiology 2022;43(5):627-633
The incidence and spread of emerging infectious diseases are highly uncertain. This paper summarizes the uncertainty and complexity of emerging infectious disease, and suggests that for the response to the varied emerging infectious diseases in the future, it is still necessary for human to take the strategy of constantly strengthening the prevention and control capability and improving various preparedness protocols. For the better response to emerging infectious diseases and protection of people's health and life, the following measures can be taken, paying more attention to the layout of the infectious disease surveillance network, establishing and maintaining the laboratory surveillance network of infectious diseases, establishing and improving a "wartime-peacetime" transition mechanism or system of medical treatment and response, developing and improving the prevention and control plan for emerging infectious diseases, strengthening the training and rehearsal of emerging infectious disease treatment and response, establishing and improving the system for the grading, classification and stockpile of medical supplies for public health emergency response and establishing and maintaining the system of early warning of emerging infectious diseases and technical platform regulations.
Communicable Diseases/epidemiology*
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Communicable Diseases, Emerging/prevention & control*
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Disease Outbreaks/prevention & control*
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Humans
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Public Health
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Uncertainty