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Background The initial cases of novel coronavirus (2019-nCoV)–infected pneumonia (NCIP) occurred in Wuhan, Hubei Province, China, in December 2019 and January 2020. We analyzed data on the first 425 confirmed cases in Wuhan to determine the epidemiologic characteristics of NCIP. Methods We collected information on demographic characteristics, exposure history, and illness timelines of laboratory-confirmed cases of NCIP that had been reported by January 22, 2020. We described characteristics of the cases and estimated the key epidemiologic time-delay distributions. In the early period of exponential growth, we estimated the epidemic doubling time and the basic reproductive number. Results Among the first 425 patients with confirmed NCIP, the median age was 59 years and 56% were male. The majority of cases (55%) with onset before January 1, 2020, were linked to the Huanan Seafood Wholesale Market, as compared with 8.6% of the subsequent cases. The mean incubation period was 5.2 days (95% confidence interval [CI], 4.1 to 7.0), with the 95th percentile of the distribution at 12.5 days. In its early stages, the epidemic doubled in size every 7.4 days. With a mean serial interval of 7.5 days (95% CI, 5.3 to 19), the basic reproductive number was estimated to be 2.2 (95% CI, 1.4 to 3.9). Conclusions On the basis of this information, there is evidence that human-to-human transmission has occurred among close contacts since the middle of December 2019. Considerable efforts to reduce transmission will be required to control outbreaks if similar dynamics apply elsewhere. Measures to prevent or reduce transmission should be implemented in populations at risk. (Funded by the Ministry of Science and Technology of China and others.)

Background: Emergency Operations Center (EOC) is a place to provide response to public health emergencies. Chinese Center for Disease Control and Prevention (China CDC)’s EOC was officially established in 2016, which has been the core department for the public health emergencies and risk response. In recent years, we have been continuously improving the function of EOC through many incidents. In the study, we hope to share the construction status, operation management experience of China CDC’s EOC and the response process in the human avian influenza A (H7N9) outbreak.Main text: The China CDC’s EOC mainly focus on building the five core elements including sites/places and facilities, information and data, plans and procedures, training and exercises, and logistics. Based on summarizing previous emergency response, the China CDC’s EOC established its own incident management and the standardized response procedures. The event-specific data, context-specific data and event management data could be obtained through various source. The logistics department of the EOC also provides comprehensive support. And that the well-trained staff is another necessary conditions for its operation. Through sharing the response process of H7N9 outbreak, it further explains the EOC’s functions in the five phases of outbreak response, such as the formulation of the incident response framework, monitoring, personnel dispatch and resource mobilization.Conclusions: The EOC contributes to faster and more efficient responses during emergencies which enable a greater reduction in morbidity and mortality. Compared with the traditional incident response process, under the command and coordination of China CDC’s EOC, each group involved in the response has a clearer goal, responsibilities and tasks at each stage. Meanwhile, each group also gave full play to its own expertise and advantages. As a whole, incident response tended to be more specialized and precise, which generally improves the efficiency of incident response. However, different countries and regions have different response processes to the events. We still suggested that appropriate emergency operation plan should be made according to the complexity of incident response in the region when constructing response mechanism, through our experience. And the China CDC’s EOC is still at growing and groping phase.

Background: The EOC of Chinese Center for disease Control and Prevention (China CDC) was officially established in 2016, which has become the core department for the public health emergencies and risk response. In recent years, we have continued to improve and summarize the EOC's role and functions in different events. And we also want to share the construction status and operation management experience of the EOC of China CDC. It is also to promote the construction of global emergency operation management system.Main text: We searched the websites of WHO, USCDC and ECDC for the EOC-related concepts. And through expert interviews and personal communication with experts, we collected relevant opinions and identify additional published literature, then described the current situation of construction of China CDC’s EOC. For EOC, different organizations / agencies have different definitions. In China, the EOC is a place where CDC organizes and conducts the related emergency response work. And it is also an important part of public health emergency system construction. The China CDC’s EOC had developed a series of incident action plan (IAP) and the standardized forms for each incident. The event-specific data, context-specific data and event management data are usually obtained by different system and channel. The China CDC’s EOC would improve the staff’s abilities through an ongoing series of training and exercises. Comparing with before, the efficiency of incident response has been greatly increased after the establishment of EOC.Conclusions: The China CDC’s EOC is still growing and groping phase. It is necessary to continue theoretical learning and practice to continuously improve the capacity of the construction and operations of the EOC system. We need continued close collaboration and partnership with international organizations to enable more to be accomplished through leveraging individual institutional strengths. The standardize approach to respond to public health emergencies meet global standards needs.

Objectives To Share the construction status and operation management experience of the EOC of China CDC. It is also to promote the construction of global emergency operation management system.Methods We searched the websites of WHO, USCDC and EU CDC for the EOC-related concepts. And through expert interviews and personal communication with experts, we collected relevant opinions and identify additional published literature, then described the current situation of construction of China CDC’s EOC. Results For EOC, different organizations / agencies have different definitions. In China, the EOC is a place where CDC organizes and conducts the related emergency response work. And it is also an important part of public health emergency system construction. The China CDC’s EOC had developed a series of incident action plan (IAP) and the standardized forms for each incident. The event-specific data, context-specific data and event management data are usually obtained by different system and channel. The China CDC’s EOC would improve the staff’s abilities through an ongoing series of training and exercises. Comparing with before, the efficiency of incident response has been greatly increased after the establishment of EOC.Conclusions The China CDC’s EOC is still growing and groping phase. It is necessary to continue theoretical learning and practice to continuously improve the capacity of the construction and operations of the EOC system. We need continued close collaboration and partnership with international organizations to enable more to be accomplished through leveraging individual institutional strengths. The standardize approach to respond to public health emergencies meet global standards needs.

On the Internet, there is a lot of open access information related to infectious diseases, e.g., official announcement, media news, bulletin boards, blogs, and other social media. If proper data retrieval and screening methods were applied on these Internet-based data, it would be very useful to improve the timeliness of early detection for infectious diseases. In China, we practice early warning using Internet-based data with routine intelligence screening assessment every day, and respond to any unusual event in a timely manner. Through this mechanism, the surveillance and early warning of Internet-based data for infectious disease and public health emergency plays an important supplemental role to the traditional surveillance systems.

This chapter introduces the definition, the key elements, the contents, and the roles of surveillance in infectious disease prevention and control. Several major infectious disease surveillance systems in China are then generally introduced one by one.

This chapter introduces the history, design, technical elements, and functional framework of China Infectious Diseases Automated-alert and Response System (CIDARS). The targeted diseases, early warning methods, and response steps are also described. Based on the running data of the system from 2011 to 2013, the performance of CIDARS is analyzed and evaluated, and further direction of CIDARS is also discussed.

This chapter describes how the surveillance department conducts investigation and verification, risk assessment, and takes necessary public health actions after the early warning system detects or produces a warning signal. We need to verify the reliability and validity of the warning signal, to conduct a risk assessment to see how it may affect public health, and to advise what kind of actions are required to prevent and control a communicable disease.

Modern information technology developments provide the necessary foundation for the establishment of infectious disease surveillance and early warning systems. Multiple diseases information systems provide more comprehensive and reliable information sources for early warnings. This chapter introduces methods of the development and construction of early warning of infectious diseases, including the fundamental principles of investigation, system design, system framework and essential functions, system implementation, and system evaluation.

There was a dramatic increase in scarlet fever cases in China from March to July 2011. Group A Streptococcus (GAS) is the only pathogen known to cause scarlet fever. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) coupled to Biotyper system was used for GAS identification in 2011. A local reference database (LRD) was constructed, evaluated and used to identify GAS isolates. The 75 GAS strains used to evaluate the LRD were all identified correctly. Of the 157 suspected β-hemolytic strains isolated from 298 throat swab samples, 127 (100%) and 120 (94.5%) of the isolates were identified as GAS by the MALDI-TOF MS system and the conventional bacitracin sensitivity test method, respectively. All 202 (100%) isolates were identified at the species level by searching the LRD, while 182 (90.1%) were identified by searching the original reference database (ORD). There were statistically significant differences with a high degree of credibility at species level (χ(2)=6.052, P

To analyze the information obtained through Internet-based media surveillance in 2013 on domestic public health emergencies and to compare with the related data reported through Chinese Public Health Emergency Management Information System (PHEMIS), and to study the role of Internet-based Media Surveillance Program (IBMSP) in the detection of public health emergencies.A descriptive analysis was conducted based on the database of the information on domestic public health emergencies. Information was obtained through the Internet-based media surveillance in 2013.A total of 752 pieces of information regarding domestic public health emergencies in 31 provinces were obtained, through the IBMSP, run by the China CDC in 2013. 53.46% of all the information were categorized as initial ones on public health emergency while another 22.07% were considered as updated ones. 41.62% of the information were related to infectious diseases with another 24.73% to food poisoning. 27.53% of the information were from official websites of governments and professional organizations, with the rest 72.47% were from media. As for corresponding public health emergencies, 41.79% were food poisoning and 18.66% were infectious diseases. 22.39% of them occurred in schools, 18.16% in other organizations and 16.92% in households. 28.86% were reported through Chinese PHEMIS. For the 116 public health emergencies that both related to information obtained through Internet-based media surveillance in 2013 and reported through PHEMIS, the median days of interval between illness onset of the first case as well as reported by media, interval between onset of the first case as well as reported through PHEMIS, were 2.5 days and 2.0 days respectively. 19.83% of the emergencies were first reported by media than through PHEMIS.Internet-based media surveillance programs had become an important way to detect public health emergencies and could serve as the supplement to the classic surveillance programs on public health emergencies.

To establish a comprehensive evaluation index system for the China Public Health Emergency Events Surveillance System (CPHEESS).A draft index system was built through literature review and under the consideration of the characteristics on CPHEESS. Delphi method was adapted to determine the final index system.The index system was divided into primary, secondary and tertiary levels. There were 4 primary indicators: System structure, Network platform, Surveillance implementation reports with Data analysis and utilization. There were 16 secondary and 70 tertiary indicators being set, with System structure including 14 tertiary indicators (accounted for 20.00%), 21 Network platforms (accounted for 30.00%). Twenty-four Surveillance implementation reports (accounted for 34.29%), 11 Data analysis and utilization (accounted for 15.71%). The average score of importance of each indicators was 4.29 (3.77-4.94), with an average coefficient variation as 0.14 (0.12-0.16). The mean Chronbach's α index was 0.84 (0.81-0.89). The adaptability of each related facilities indicator was specified.The primary indicators were set in accordance with the characteristics and goals of the surveillance systems. Secondary indicators provided key elements in the management and control of the system while the tertiary indicators were available and operative. The agreement rate of experts was high with good validity and reliability. This index system could be used for CPHEESS in future.

To investigate the epidemiological characteristics of human infections with avian influenza A (H7N9) in China and to provide scientific evidence for the adjustment of preventive strategy and control measures.Demographic and epidemiologic information on human cases were collected from both reported data of field epidemiological investigation and the reporting system for infectious diseases.A total of 433 cases including 163 deaths were reported in mainland China before June 4, 2014. Two obvious epidemic peaks were noticed, in March to April, 2013 and January to February, 2014. Confirmed cases emerged in 14 areas of China. Five provinces, including Zhejiang, Guangdong, Jiangsu, Shanghai, and Hunan, reported about 85% of the total cases. Median age of the confirmed cases was 58 years (range, 1-91), with 70% as males. Of the 418 cases with available data, 87% had ever exposed to live poultry or contaminated environments. 14 clusters were identified but human to human transmission could not be ruled out in 9 clusters.Human infections with avian influenza A (H7N9) virus showed the characteristics of obvious seasonal distribution, with certain regional clusters. The majority of confirmed cases were among the elderly, with more males seen than the females. Data showed that main source of infection was live poultry and the live poultry market had played a significant role in the transmission of the virus.

To analyze the implement performance of China Infectious Diseases Automated-alert and Response System (CIDARS) of 31 provinces in mainland China, and to provide the evidences for further promoting the application and improvement of this system.The amount of signals, response situation and verification outcome of signals related to 32 infectious diseases of 31 provinces in mainland China in CIDARS were investigated from 2011 to 2013, the changes by year on the proportion of responded signals and timeliness of signal response were descriptively analyzed.A total of 960 831 signals were generated nationwide on 32 kinds of infectious diseases in the system, with 98.87% signals (949 936) being responded, and the median (the 25(th) percentile to the 75(th) percentile (P25-P75) ) of time to response was 1.0 (0.4-3.3) h. Among all the signals, 242 355 signals were generated by the fixed-value detection method, the proportion of responded signals was 96.37% (62 349/64 703), 98.75% (68 413/69 282) and 99.37% (107 690/108 370), respectively, and the median (P25-P75) of time to response was 1.3 (0.3-9.7), 0.8(0.2-4.9) and 0.7 (0.2-4.2) h, respectively. After the preliminary data verification, field investigation and laboratory test by local public health staffs, 100 232 cases (41.36%) were finally confirmed.In addition, 718 476 signals were generated by the temporal aberration detection methods, and the average amount of signal per county per week throughout the country were 1.53, and 8 155 signals (1.14%) were verified as suspected outbreaks. During these 3 years, the proportion of signal response was 98.89% (231 149/233 746), 98.90% (254 182/257 015) and 99.31% (226 153/227 715), respectively, and the median (P25-P75) of time to response was 1.1 (0.5-3.3), 1.0 (0.5-2.9) and 1.0 (0.5-2.6) h, respectively.From 2011 to 2013, the proportion of responded signals and response timeliness of CIDARS maintained a rather high level, and further presented an increasing trend year by year. But the proportion of signals related to suspected outbreaks should be improved.

In mainland China, most avian influenza A(H7N9) cases in the spring of 2013 were reported through the pneumonia of unknown etiology (PUE) surveillance system. To understand the role of possible underreporting and surveillance bias in assessing the epidemiology of subtype H7N9 cases and the effect of live-poultry market closures, we examined all PUE cases reported from 2004 through May 3, 2013. Historically, the PUE system was underused, reporting was inconsistent, and PUE reporting was biased toward A(H7N9)-affected provinces, with sparse data from unaffected provinces; however, we found no evidence that the older ages of persons with A(H7N9) resulted from surveillance bias. The absolute number and the proportion of PUE cases confirmed to be A(H7N9) declined after live-poultry market closures (p

Timely reporting, effective analyses and rapid distribution of surveillance data can assist in detecting the aberration of disease occurrence and further facilitate a timely response. In China, a new nationwide web-based automated system for outbreak detection and rapid response was developed in 2008. The China Infectious Disease Automated-alert and Response System (CIDARS) was developed by the Chinese Center for Disease Control and Prevention based on the surveillance data from the existing electronic National Notifiable Infectious Diseases Reporting Information System (NIDRIS) started in 2004. NIDRIS greatly improved the timeliness and completeness of data reporting with real-time reporting information via the Internet. CIDARS further facilitates the data analysis, aberration detection, signal dissemination, signal response and information communication needed by public health departments across the country. In CIDARS, three aberration detection methods are used to detect the unusual occurrence of 28 notifiable infectious diseases at the county level and transmit information either in real time or on a daily basis. The Internet, computers and mobile phones are used to accomplish rapid signal generation and dissemination, timely reporting and reviewing of the signal response results. CIDARS has been used nationwide since 2008; all Centers for Disease Control and Prevention (CDC) in China at the county, prefecture, provincial and national levels are involved in the system. It assists with early outbreak detection at the local level and prompts reporting of unusual disease occurrences or potential outbreaks to CDCs throughout the country.

BACKGROUND: The first identified cases of avian influenza A(H7N9) virus infection in humans occurred in China during February and March 2013. We analyzed data obtained from field investigations to describe the epidemiologic characteristics of H7N9 cases in China identified as of December 1, 2013. METHODS: Field investigations were conducted for each confirmed case of H7N9 virus infection. A patient was considered to have a confirmed case if the presence of the H7N9 virus was verified by means of real-time reverse-transcriptase–polymerase-chain-reaction assay (RT-PCR), viral isolation, or serologic testing. Information on demographic characteristics, exposure history, and illness timelines was obtained from patients with confirmed cases. Close contacts were monitored for 7 days for symptoms of illness. Throat swabs were obtained from contacts in whom symptoms developed and were tested for the presence of the H7N9 virus by means of real-time RT-PCR. RESULTS: Among 139 persons with confirmed H7N9 virus infection, the median age was 61 years (range, 2 to 91), 71% were male, and 73% were urban residents. Confirmed cases occurred in 12 areas of China. Nine persons were poultry workers, and of131 persons with available data, 82% had a history of exposure to live animals, including chickens (82%). A total of 137 persons (99%) were hospitalized, 125 (90%) had pneumonia or respiratory failure, and 65 of 103 with available data (63%) were admitted to an intensive care unit. A total of 47 persons (34%) died in the hospital after a median duration of illness of 21 days, 88 were discharged from the hospital, and 2 remain hospitalized in critical condition; 2 patients were not admitted to a hospital. In four family clusters, human-to-human transmission of H7N9 virus could not be ruled out. Excluding secondary cases in clusters, 2675 close contacts of case patients completed the monitoring period; respiratory symptoms developed in 28 of them (1%); all tested negative for H7N9 virus. CONCLUSIONS: Most persons with confirmed H7N9 virus infection had severe lower respiratory tract illness, were epidemiologically unrelated, and had a history of recent exposure to poultry. However, limited, nonsustained human-to-human H7N9 virus transmission could not be ruled out in four families.

Timely reporting, effective analyses and rapid distribution of surveillance data can assist in detecting the aberration of disease occurrence and further facilitate a timely response. In China, a new nationwide web-based automated system for outbreak detection and rapid response was developed in 2008. The China Infectious Disease Automated-alert and Response System (CIDARS) was developed by the Chinese Center for Disease Control and Prevention based on the surveillance data from the existing electronic National Notifiable Infectious Diseases Reporting Information System (NIDRIS) started in 2004. NIDRIS greatly improved the timeliness and completeness of data reporting with real time reporting information via the Internet. CIDARS further facilitates the data analysis, aberration detection, signal dissemination, signal response and information communication needed by public health departments across the country. In CIDARS, three aberration detection methods are used to detect the unusual occurrence of 28 notifiable infectious diseases at the county level and to transmit that information either in real-time or on a daily basis. The Internet, computers and mobile phones are used to accomplish rapid signal generation and dissemination, timely reporting and reviewing of the signal response results. CIDARS has been used nationwide since 2008; all Centers for Disease Control and Prevention (CDC) in China at the county, prefecture, provincial and national levels are involved in the system. It assists with early outbreak detection at the local level and prompts reporting of unusual disease occurrences or potential outbreaks to CDCs throughout the country.

Summary Background The novel influenza A H7N9 virus emerged recently in mainland China, whereas the influenza A H5N1 virus has infected people in China since 2003. Both infections are thought to be mainly zoonotic. We aimed to compare the epidemiological characteristics of the complete series of laboratory-confirmed cases of both viruses in mainland China so far. Methods An integrated database was constructed with information about demographic, epidemiological, and clinical variables of laboratory-confirmed cases of H7N9 (130 patients) and H5N1 (43 patients) that were reported to the Chinese Centre for Disease Control and Prevention until May 24, 2013. We described disease occurrence by age, sex, and geography, and estimated key epidemiological variables. We used survival analysis techniques to estimate the following distributions: infection to onset, onset to admission, onset to laboratory confirmation, admission to death, and admission to discharge. Findings The median age of the 130 individuals with confirmed infection with H7N9 was 62 years and of the 43 with H5N1 was 26 years. In urban areas, 74% of cases of both viruses were in men, whereas in rural areas the proportions of the viruses in men were 62% for H7N9 and 33% for H5N1. 75% of patients infected with H7N9 and 71% of those with H5N1 reported recent exposure to poultry. The mean incubation period of H7N9 was 3·1 days and of H5N1 was 3·3 days. On average, 21 contacts were traced for each case of H7N9 in urban areas and 18 in rural areas, compared with 90 and 63 for H5N1. The fatality risk on admission to hospital was 36% (95% CI 26–45) for H7N9 and 70% (56–83%) for H5N1. Interpretation The sex ratios in urban compared with rural cases are consistent with exposure to poultry driving the risk of infection—a higher risk in men was only recorded in urban areas but not in rural areas, and the increased risk for men was of a similar magnitude for H7N9 and H5N1. However, the difference in susceptibility to serious illness with the two different viruses remains unexplained, since most cases of H7N9 were in older adults whereas most cases of H5N1 were in younger people. A limitation of our study is that we compared laboratory-confirmed cases of H7N9 and H5N1 infection, and some infections might not have been ascertained. Funding Ministry of Science and Technology, China; Research Fund for the Control of Infectious Disease and University Grants Committee, Hong Kong Special Administrative Region, China; and the US National Institutes of Health.