Received Date: May 05, 2013; Accepted Date: December 28, 2013; Published Date: December 30, 2013
Citation: Sugishita Y, Ohkusa Y, Sugawara T, Shimatani N, Nadaoka Y, et al. (2013) Enhanced Syndromic Surveillance for the Fourth Japan-China-South Korea Trilateral Summit 2011. J Bioterr Biodef 4:126 doi: 10.4172/2157-2526.1000126
Copyright: © 2013 Sugishita Y, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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Background: When high profile events such as mass gatherings or political events are held, syndromic surveillances are enhanced to quickly detect health emergencies. Drawing on past experiences, enhanced surveillance was conducted during the Fourth Japan-China-South Korea Trilateral Summit (May 21-22, 2011). This report describes the details and results of the enhanced syndromic surveillance. Methods: Enhanced surveillance started on May 18, and ended on June 4, two weeks after the meeting, using three existing surveillance systems that operate routinely: Official Syndromic Surveillance, Ambulance Transfer Syndromic Surveillance, and Pharmacy Surveillance. The enhanced surveillance was a joint work between the Tokyo Metropolitan Government and the National Institute of Infectious Diseases. Information from the three surveillance systems was mutually exchanged and daily risk assessment on potential health emergencies such as bioterrorism and potential epidemics of infectious diseases was performed jointly. Results: During the enhanced surveillance period, the only case that required verification was one suspected measles case from the report in the Official Syndromic Surveillance. None of the cases in the Ambulance Transfer Syndromic Surveillance or the Pharmacy Surveillance required additional investigation. All three syndromic surveillance systems that were utilized for the enhanced surveillance are run routinely, and the enhancement areas were simply conducting the daily risk assessment and reporting. Therefore, the enhanced surveillance is conducted only by agreements and arrangements among members. In spite of very short notice, we were able to initiate the enhanced surveillance because the existing surveillance required no baseline or other preparation. The burden of implementation of surveillance was significantly small in comparison with the previous enhanced surveillance. Conclusions: It is possible to activate the enhanced surveillance arrangements whenever needed. We were able to make a comprehensive assessment by utilizing three syndromic surveillance systems, which we believe are useful in detecting a possible case of bioterrorism.
Surveillance system; Biological terrorism; Official syndromic surveillance; Ambulance transfer surveillance; Pharmacy surveillance
When high profile events such as Summit meetings, Olympic Games, FIFA (Fédération Internationale de Football Association) World Cup, or other mass gatherings or political events are held, syndromic surveillances are enhanced to quickly detect health emergencies such as bioterrorism and epidemics of infectious diseases [1-9]. Enhanced syndromic surveillance in Japan has been conducted in the past at the Kyushu Okinawa G8 summit (Group of Eight Summit) 2000 [3,4], the FIFA World Cup 2002 competition [5,6], the Hokkaido Toyako G8 summit meeting 2008 , President Obama’s visit to Japan in 2009 , the Yokohama APEC (Asia-Pacific Economic Cooperation) 2010, and the Nagoya COP10 (the tenth meeting of the Conference of the Parties) 2010 .
Drawing on these past experiences, enhanced syndromic surveillance was conducted during the Fourth Japan–China–South Korea Trilateral Summit (May 21–22, 2011). This was done by utilizing the surveillance systems that are already run on a daily basis, with enhancements on sharing of information between parties that normally conduct surveillances on its own, making a daily report, conducting risk assessment on a daily basis, and structuring a response framework when additional action is deemed necessary. This report describes the overview and the details of the enhanced syndromic surveillance, and through the results of this study, we identified both the usability and issues of the existing system, and to provide fundamental information that would be useful for the implementation of enhanced syndromic surveillance for mass gatherings in the future.
In Japan, surveillances of infectious diseases are conducted regularly. In the Infectious Diseases Control Law, all infectious diseases classified in categories I through V and two diseases categorized as “pandemic influenza and relevant infections,” are designated as targets of the National Epidemiological Surveillance of Infectious Diseases (NESID). For the 60 infectious diseases classified in categories I through IV and 18 diseases in category V, all cases are required for notification. For the 27 diseases and 2 syndromes in category V, the cases are reported only from the sentinel clinics and hospitals.
However, these surveillances are based on data after the diagnosis is made, which makes them insufficient for surveillances in high profile events where speed for information gathering and action becomes more significant. To support these surveillances through NESID, Japan has implemented several syndromic-based surveillance systems, both official (regulated under the Infectious Diseases Control Law) and unofficial, as complementary surveillance systems. The targeted diseases of the Official Sydromic Surveillance (OSS) are acute febrile disease, respiratory disease and exanthematous disease. These cases are reported promptly after being examined by a doctor from the sentinel clinics and hospitals. As complementary surveillance systems, Pharmacy Surveillance (PS, conducted nationally) and Ambulance Transfer Syndromic Surveillance (ATSS, operating in the Tokyo Metropolitan area) are performed on a regular basis.
Surveillance at the Hokkaido Toyako G8 summit meeting in July 2008 was the first full-scale enhanced syndromic surveillance in Japan. Four types of syndromic surveillance systems were performed during the summit. As existing systems, OSS and PS were utilized. As new systems, ATSS and syndromic surveillance for OTC (non-prescribed, over-the-counter) drug sales were performed for the duration of the enhanced surveillance for the summit. Additionally, data related to health conditions of residents were collected from nearby neighbourhoods. Surveillance started on June 23, two weeks before the summit, and ended on July 23, two weeks after the closing of the meeting.
When President Obama visited Tokyo on November 13–14, 2009, three syndromic surveillance systems were selected: OSS, PS, and ATSS. As opposed to the surveillance for the Hokkaido Toyako G8 summit, which was conducted on more experimental terms, the surveillance for the president’s visit was designed as an actually viable and sustainable system. For example, syndromic surveillance for OTC drug sales was not performed, because this surveillance required buying information from the OTC drug companies, which proved to be too costly. Also, all three surveillances selected were existing systems. Therefore, baseline data had already been obtained prior to the president’s visit, making this surveillance a highly efficient and viable system. The enhanced surveillance was conducted until two weeks after the meeting was held. The enhancement from the routine surveillance was simply building a framework for information sharing, reporting, risk assessment, and readiness for action.
As a joint work between the Tokyo Metropolitan Government (TMG) and the National Institute of Infectious Diseases (NIID), enhanced syndromic surveillance was performed from May 18, three days before the summit meeting, to June 4, two weeks after the meeting. Three existing surveillance systems, OSS, ATSS, and PS, which operates routinely, were utilized. Information from OSS and ATSS were collected at the Tokyo Metropolitan Institute of Public Health (TMIPH), and information from PS was collected at NIID. Information from the three surveillance systems were then mutually exchanged, and daily riskassessment on potential health emergencies such as bioterrorism and potential epidemics of infectious diseases was performed jointly. The enhancements of the routine surveillance process involved: sharing of information, daily situation reporting, daily risk assessment, and readiness for action when needed.
Official Syndromic Surveillance (OSS)
OSS, based on the Infectious Diseases Control Law, started on April 1, 2008. When a physician at the designated medical facility (sentinel clinic or hospital) sees a patient meeting the reporting criteria, the facility must immediately report to the public health center via internet or fax. There are 443 designated medical facilities in Tokyo. The report criteria are the following: (1) fever over 38°C and respiratory symptoms (except for external injury or organic cause) (respiratory symptoms refers to critical cases that must be admitted to a hospital) and (2) fever and rash or blistering skin disease (except for symptoms that are clearly from diseases classified in categories II~IV, under the Law). Throughout the duration of the enhanced surveillance, fever and rash or blistering skin disease (criteria (2)) was especially monitored closely for surveillance of bioterrorism using smallpox.
Ambulance Transfer Syndromic Surveillance (ATSS)
From the results of fundamental studies conducted since 2005 , TMG adopted the ATSS system as a countermeasure against bioterrorism attack, outbreak of infectious diseases, and other health risk incidents. After making a test installation in 2008, the actual operation began in 2011. This surveillance system covers the Tokyo Metropolitan area almost entirely, excluding Inagi city and the small islands off the coast of Tokyo. This surveillance system captures the data of around 600 thousand ambulance transfers per year that is initially recorded in the emergency record system. The surveillance system then rapidly analyses the information regarding the symptoms of each patient, recorded during ambulance transfer (Table 1).
|1||Chiyoda Ward||2||Chuo Ward||3||Minato Ward||4||Shinjuku Ward||5||Bunkyo Ward|
|6||Taito Ward||7||Sumida Ward||8||Koto Ward||9||Shinagawa Ward||10||Meguro Ward|
|11||Ota Ward||12||Setagaya Ward||13||Shibuya Ward||14||Nakano Ward||15||Suginami Ward|
|16||Toshima Ward||17||Kita Ward||18||Arakawa Ward||19||Itabashi Ward||20||Nerima Ward|
|21||Adachi Ward||22||Katsushika Ward||23||Edogawa Ward||24||Hachioji City||25||Machida City|
|26||Kodaira City and Nishitokyo City||27||Higashikurume City, Higashimurayama City, and Kiyose City|
|28||Fuchu City, Chofu City, and Komae City||29||Musashino City, Mitaka City, and Koganei City|
|30||Kokubunji City, Kunitachi City, Tachikawa City, and Akishima City||31||Higashiyamato City and Musashimurayama City|
|32||Ome City, Fussa City, Hamura City, Akiruno City, Mizuho Town, Okutama Town, Hinode Town, and Hinohara Village||33||Hino City and Tama City|
Table 1: List of areas covered under the Ambulance Transfer Syndromic Surveillance Thirty-three areas are divided into surveillance units in the Ambulance Transfer Syndromic Surveillance of Tokyo, which covers 52 municipalities excluding Inagi city and islands off the coast of Tokyo.
The data that is captured in the surveillance system are those cases that are classified as acute diseases, or cases that have a record of one or more of the four chief complaints: fever, diarrhoea, vomiting, and rash. 10 items (date, day of the week, time, address, sex, age, degree of severity, disease, transferred hospital, and chief complaint) are captured for each case on a daily basis. During patient transportation, the ambulance crew also enters clinical conditions classified into 12 categories: Vomiting/Nausea, Dizziness, Palpitation, Unconsciousness, Breathing disorder, Fever, Spasm/Paralysis, Collapse/Weakness, Bloody emesis/Nasal hemorrhage, Rash, Headache, and Diarrhoea/Bloody stool. This data on the clinical conditions is used for analysis through the surveillance system.
Data entered by 8:00 AM is analyzed through the system. Data entered after 8:00 AM are analyzed with a delay of one day. Analyses are performed using a statistical algorithm developed by the Infectious Disease Surveillance Center at NIID . Aberration is defined through a multiple linear regression model. The model regresses the share of transported patients across the entire Tokyo Metropolitan area for the week number (1–52, 53), the day of the week (Sunday–Saturday), holidays and day after holidays, and time trends, such that the following equation is used with linear regression for area “k” at date “t”, i.e.
Number of cases in area k at date t/Number of cases in the entire Tokyo Metropolitan are =
Three criteria are used for aberration: low level (if the probability of the ratio of observed cases that occur is less than 2.5%); medium level (less than 1%); and high level (less than 0.1%). For the analysis, Tokyo was divided into 33 areas as surveillance units (23 wards, 2 cities and 8 districts; we have defined districts by dividing 23 cities, 3 towns and 1 village into 8 units).
Pharmacy Surveillance (PS)
After a thorough fundamental study, PS is being performed nationally since January 2009 [11,12]. At the time of the summit, around 789 pharmacies in Tokyo were participating in the surveillance, accounting for about 14% of the total number of pharmacies. In this surveillance, only data that is collected is the number of prescriptions made, classified into therapeutic categories. Therefore, the collected data does not include any personal information. The data on number of prescriptions is automatically extracted and analyzed daily, through the receipt computer (type: Application Service Provider (ASP)). The surveillance monitors drugs categorized under, “relief of fever and pain”, “drugs for common colds”, “antibiotics”, “anti-influenza virus drugs” (excluding for Amantadine), and “anti-Varicella-Zoster Virus drugs”, with the last two categories further sub-classified by age: “younger than 15”, “16–64”, and “older than 65 years old”. As surveillance for a potential bioterrorism using smallpox, we monitored the change in prescription of acyclovir to adults, without increase in the population of children or the elderly.
The aberration detection procedure is similar to ATSS, but the dependent variable is the number of cases, rather than the ratio in an area:
Number of cases at date t =
The independent variables are the same as estimated equation for the ambulance transfer. Three criterions for aberration of each pharmacy are the same as ATSS.
The surveillance units for the coverage area of PS is basically defined as administrative districts such as city or town, but if the number of corporate pharmacies in an administrative district is less than ten, we defined an area by joining the neighbouring districts so that each area has more than 10 pharmacies. Area aberration is defined as low level (if the proportion of the pharmacies with high level aberration is higher than 10% but less than 20%), medium level (if the proportion is higher than 20% but less than 30%, and the number of the pharmacies is more than three); high level (if the proportion is higher than 30%, and the number of the pharmacies is more than four).
Information from the three surveillance systems was shared between TMIPH and NIID, to jointly perform daily risk-assessment on potential health emergencies.
The following action steps were taken as response to the surveillance data. Every morning, the surveillance data of the previous day was assessed. For OSS, if there was a reported case, we made an inquiry to the corresponding public health center for verification. For ATSS, if there was a high level aberration, we confirmed if there was any accumulation in the data, such as time, person, and place. If any accumulation was suspected, we verified with the corresponding public health center. For PS, if there was a high level aberration, we confirmed with the nearby sentinel clinics or hospitals via corresponding public health centers to confirm to see if there was any unusual case.
Figure 1 shows the number of aberrations in ATSS during the enhanced surveillance period. Figure 2 shows the number of aberrations from PS. For Figures 1 and 2, the symptom or therapeutic category is specified for the medium and high-level aberrations, with the location of the incident in parenthesis. Figure 3 portrays a sample of the daily situation report. This sample report for May 18, 2011 has only one middle level aberration in the Chuo Ward for antibiotic drugs, shaded in grey. Comments are added in the bottom of the chart and sent to the relevant institutions.
Figure 1: Number of aberrations in the Ambulance Transfer Syndromic Surveillance. Number of aberrations in the Ambulance Transfer Syndromic Surveillance during the enhanced surveillance period at the Fourth Japan–China–South Korea trilateral summit in May 2011. Syndrome I presented in this figure indicates Bloody emesis/Nasal hemorrhage.
Official Syndromic Surveillance (OSS)
One case meeting the reporting criterion (2) was reported from a medical facility in Higashimurayama city on May 23. Verification by telephone revealed a suspected measles case. Therefore, the response to measles was taken by the corresponding health center.
Ambulance Transfer Syndromic Surveillance (ATSS)
Surveillance for ambulance transfer found 10 high aberrations during the enhanced surveillance period. Nine of them showed high aberration in Bloody emesis/Nasal hemorrhage. The other was aberration in palpitation. Risk assessment was made for each of the cases to judge whether further investigation was necessary. It was concluded that none of the cases required additional investigation.
Pharmacy Surveillance (PS)
High level aberration was not detected. 24 medium level aberrations were detected, but no case required additional investigation.
Every day during the enhanced surveillance period, including nonworking days, information from PS was collected at NIID by 7:00 AM, and the information from ATSS and OSS were collected at TMIPH by 9:00 AM. After sharing surveillance information, virtual conferences by email or telephone were held between TMIPH and NIID to discuss whether further investigation was needed. A daily situation report was published by 10:30 AM. During the enhanced surveillance period, the only case that required verification was one suspected measles case from OSS.
Because OSS is a legally established surveillance, it is easier to take a response after aberration detection. Also, since this syndromic surveillance has been operating routinely, no extra expense or system construction is necessary for initiating an enhanced surveillance. Additionally, it is expected that specificity of surveillance is high because case reporting is made by doctors. On the other hand, we believe that the sensitivity is low. For example, when influenza or chickenpox is diagnosed clinically, there is no need to report it because a diagnosis has been made. However, there is a high probability that rare diseases such as smallpox or anthrax are misdiagnosed as influenza, chickenpox, or other more common diseases. Also we believe that having a coordinated system that allows for rapid verification of the reported cases is important for the surveillance to be more effective. During the enhanced surveillance period, one suspected measles case was reported and verified. Therefore, it was confirmed that OSS is being executed properly, at least for Tokyo.
This surveillance system for ambulance transfer is fully automated, imposing no burden on ambulance teams other than their routine tasks. The aberrations in this surveillance are reported when there is significant statistical increase compared with the past data. The public health agency monitors the deviations from the baseline and makes the assessment based on the aberration levels. The surveillance frequently reported aberrations in Bloody emesis/Nasal haemorrhage, even though the overall rate of Bloody emesis/Nasal hemorrhage is low. Therefore, for these types of syndromes which do not have a high level of ambulance transfer, even a single transportation can cause higher-level aberrations. Transportation of diarrhea in the Yokohama APEC2010 indicated a similar tendency. For the future, criteria of the aberration detection might need to be adjusted. However, because arbitrary adjustment can lead to reduced sensitivity in aberration detection, careful discussion is needed.
Regarding PS, system construction had already been finished and no extra expenses were necessary. There is also no burden to data entry and the process is fully automated. In addition, sensitivity is high and the promptness of response is comparatively high, as the data is analyzed within 24 hour of a visit to the doctor. There is also no risk of information being left out. Currently, no effective surveillance related to chickenpox or zoster in adults is executed through other surveillance systems. Therefore, PS plays an important part. Fortunately, no highlevel aberration of anti-Varicella-Zoster Virus drugs occurred during the summit. If an increase of the prescription of anti-Varicella-Zoster Virus drugs to adults were found without an increase in children or the elderly, then a confirmation needs to be made to the medical facility. However, the challenge for PS is that it is hard to take action when an aberration is detected. In Tokyo, we have not experienced a case where verification was made with the medical facility through the public health center. We should hold a study/ training session to brainstorm how we can best arrange a framework for verification with the medical facility when aberrations are detected through PS.
TMG has had experience of conducting enhanced syndromic surveillance during the Yokohama APEC2010 and during President Obama’s visit to Japan. Also, ATSS operates routinely, with cooperation between TMIPH and NIID. Therefore, assessment and response handlings during the enhanced surveillance period were conducted smoothly.
All the methods of syndromic surveillance that were utilized for the enhanced surveillance are run routinely. Therefore, the enhanced surveillance is conducted only by agreements and arrangements among members, without need for lengthy preparation. The National Police Agency asked NIID for strengthened management of pathogens on May 17, 2011, when we were first informed that the summit would be held on May 21–22, 2011. In spite of very short notice, there was no problem on the start of the enhanced surveillance because the existing surveillance required no baseline or other preparation. The burden of implementation of surveillance was significantly small in comparison with the enhanced surveillance conducted for the Hokkaido Toyako G8 summit meeting, the Yokohama APEC2010 and the Nagoya COP10.
By gathering data on symptoms, the purpose of a syndromic surveillance is assessing the risks of a possible outbreak of an illness and taking necessary action from a public health perspective. In the enhanced surveillance conducted in this report, we were able to make a comprehensive assessment by utilizing several syndromic surveillance systems, which we believe are useful in detecting a possible case of bioterrorism.
Enhanced surveillance was conducted during the 4th Japan–China– South Korea Trilateral Summit in Tokyo, Japan as a countermeasure against bioterrorism attack and other health emergencies from May 21 through 22, 2011. The surveillance used in this enhanced surveillance is operating routinely. Therefore, enhancements were easily achieved through arrangements between the parties involved, which required almost no preparation period. The burden of implementation of surveillance was apparently very small in comparison with the enhanced surveillance at the Hokkaido Toyako G8 summit meeting, the Yokohama APEC2010, and the Nagoya COP10.
Even though the start date of the summit was not clear until immediately before the meetings began, we were able to show that by utilizing the routine surveillance systems, it is possible to activate the enhanced surveillance arrangements whenever needed. Therefore, similar enhanced surveillances can be arranged for any mass gatherings in the future. Also, we were able to confirm that the existing surveillance systems are functioning effectively and are a useful tool in detecting health emergencies such as potential bioterrorism and potential epidemics of infectious diseases. However, there are several issues with the current systems that we should look to improve in the future. The issues are summarized below:
1. In Official Syndromic Surveillance, although specificity of surveillance is believed to be high, as case reportings are made by doctors, the sensitivity is believed to be low. Also, there should be a coordinated system that allows for faster verification of the reported cases.
2. In Ambulance Transfer Syndromic Surveillance, for syndromes that do not have a high level of ambulance transfer, even a single transportation can cause higher-level aberrations.
3. In Pharmacy Surveillance, it is hard to take action when an aberration is detected. To date, we have not experienced a case where verification was made with the medical facility.
We appreciate EM Systems Co. Ltd. for their cooperation in PS, a system jointly arranged by the EM Systems Co. Ltd. and NIID. We also thank the Tokyo Fire Department for the data input for ATSS.
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