Syndromic surveillance: two decades experience of sustainable systems - its people not just data!

Syndromic surveillance is a form of surveillance that generates information for public health action by collecting, analysing and interpreting routine health-related data on symptoms and clinical signs reported by patients and clinicians rather than being based on microbiologically or clinically confirmed cases. In England, a suite of national real-time syndromic surveillance systems (SSS) have been developed over the last 20 years, utilising data from a variety of health care settings (a telehealth triage system, general practice and emergency departments). The real-time systems in England have been used for early detection (e.g. seasonal influenza), for situational awareness (e.g. describing the size and demographics of the impact of a heatwave) and for reassurance of lack of impact on population health of mass gatherings (e.g. the London 2012 Olympic and Paralympic Games).We highlight the lessons learnt from running SSS, for nearly two decades, and propose questions and issues still to be addressed. We feel that syndromic surveillance is an example of the use of 'big data', but contend that the focus for sustainable and useful systems should be on the added value of such systems and the importance of people working together to maximise the value for the public health of syndromic surveillance services.

Novel public health risk assessment process developed to support syndromic surveillance for the 2012 Olympic and Paralympic Games.

Background: Syndromic surveillance aims to provide early warning and real time estimates of the extent of incidents; and reassurance about lack of impact of mass gatherings. We describe a novel public health risk assessment process to ensure those leading the response to the 2012 Olympic Games were alerted to unusual activity that was of potential public health importance, and not inundated with multiple statistical 'alarms'. Methods: Statistical alarms were assessed to identify those which needed to result in 'alerts' as reliably as possible. There was no previously developed method for this. We identified factors that increased our concern about an alarm suggesting that an 'alert' should be made. Results: Between 2 July and 12 September 2012, 350 674 signals were analysed resulting in 4118 statistical alarms. Using the risk assessment process, 122 'alerts' were communicated to Olympic incident directors. Conclusions: Use of a novel risk assessment process enabled the interpretation of large number of statistical alarms in a manageable way for the period of a sustained mass gathering. This risk assessment process guided the prioritization and could be readily adapted to other surveillance systems. The process, which is novel to our knowledge, continues as a legacy of the Games.

London 2012 Olympic and Paralympic Games: public health surveillance and epidemiology.

Mass gatherings are regarded as potential risks for transmission of infectious diseases, and might compromise the health system of countries in which they are hosted. The evidence for increased transmission of infectious diseases at international sporting mass gatherings that attract many visitors from all over the world is not clear, and the evidence base for public health surveillance, epidemiology, and response at events such as the Olympics is small. However, infectious diseases are a recognised risk, and public health planning is, and should remain, a crucial part of the overall planning of sporting events. In this Series paper, we set out the planning and the surveillance systems that were used to monitor public health risks during the London 2012 Olympic and Paralympic Games in the summer of 2012, and draw attention to the public health issues-infectious diseases and chemical, radiation, and environmental hazards-that arose. Although the absolute risk of health-protection problems, including infectious diseases, at sporting mass gatherings is small, the need for reassurance of the absence of problems is higher than has previously been considered; this could challenge conventional public health surveillance systems. Recognition of the limitations of health-surveillance systems needs to be part of the planning for future sporting events.

Contact tracing for influenza A(H1N1)pdm09 virus-infected passenger on international flight.

In April 2009, influenza A(H1N1)pdm09 virus infection was confirmed in a person who had been symptomatic while traveling on a commercial flight from Mexico to the United Kingdom. Retrospective public health investigation and contact tracing led to the identification of 8 additional confirmed cases among passengers and community contacts of passengers.

Establishing an emergency department syndromic surveillance system to support the London 2012 Olympic and Paralympic Games.

BACKGROUND: The London 2012 Olympic and Paralympic Games is a mass gathering event that will present a major public health challenge. The Health Protection Agency, in collaboration with the College of Emergency Medicine, has established the Emergency Department Sentinel Syndromic Surveillance System (EDSSS) to support the public health surveillance requirements of the Games. METHODS: This feasibility study assesses the usefulness of EDSSS in monitoring indicators of disease in the community. Daily counts of anonymised attendance data from six emergency departments across England were analysed by patient demographics (age, gender, partial postcode), triage coding and diagnosis codes. Generic and specific syndromic indicators were developed using aggregations of diagnosis codes recorded during each attendance. RESULTS: Over 339,000 attendances were recorded (26 July 2010 to 25 July 2011). The highest attendances recorded on weekdays between 10:00 and 11:00 and on weekends between 12:00 and 13:00. The mean daily attendance per emergency department was 257 (range 38-435). Syndromic indicators were developed including: respiratory, gastrointestinal, cardiac, acute respiratory infection, gastroenteritis and myocardial ischaemia. Respiratory and acute respiratory infection indicators peaked during December 2010, concomitant with national influenza activity, as monitored through other influenza surveillance systems. CONCLUSIONS: The EDSSS has been established to provide an enhanced surveillance system for the London 2012 Olympics. Further validation of the data will be required; however, the results from this initial descriptive study demonstrate the potential for identifying unusual and/or severe outbreaks of infectious disease, or other incidents with public health impact, within the community.

Lessons learned from handling a large rural outbreak of Legionnaires' disease: Hereford, UK 2003.

The outbreak of Legionnaires' disease that occurred in Hereford, West Midlands UK in 2003 was the single largest outbreak of Legionnaires' in Hereford and one of the first to challenge the newly formed Health Protection Agency. This was, de facto a 'public health incident' requiring not only the investigation and management of a community outbreak of infectious disease, but also one that had to take into account other issues including: uncertainty regarding roles and responsibilities, political considerations and communication needs including sustained media attention. The incident also demonstrated the 'added value' of an integrated health protection response. The practical lessons learned from outbreaks are rarely described, particularly operational aspects. This paper summarises the outbreak, outlines specific elements of the response and identifies some of the key learning points for the new Agency and its partners. A number of these lessons have a generic applicability to the handling of public health incidents.

An Observational Study Using English Syndromic Surveillance Data Collected During the 2012 London Olympics - What did Syndromic Surveillance Show and What Can We Learn for Future Mass-gathering Events?

Introduction In preparation for the London 2012 Olympic Games, existing syndromic surveillance systems operating in England were expanded to include daily general practitioner (GP) out-of-hours (OOH) contacts and emergency department (ED) attendances at sentinel sites (the GP OOH and ED syndromic surveillance systems: GPOOHS and EDSSS). Hypothesis/Problem The further development of syndromic surveillance systems in time for the London 2012 Olympic Games provided a unique opportunity to investigate the impact of a large mass-gathering event on public health and health services as monitored in near real-time by syndromic surveillance of GP OOH contacts and ED attendances. This can, in turn, aid the planning of future events. METHODS: The EDSSS and GPOOHS data for London and England from July 13 to August 26, 2012, and a similar period in 2013, were divided into three distinct time periods: pre-Olympic period (July 13-26, 2012); Olympic period (July 27 to August 12); and post-Olympic period (August 13-26, 2012). Time series of selected syndromic indicators in 2012 and 2013 were plotted, compared, and risk assessed by members of the Real-time Syndromic Surveillance Team (ReSST) in Public Health England (PHE). Student's t test was used to test any identified changes in pattern of attendance. RESULTS: Very few differences were found between years or between the weeks which preceded and followed the Olympics. One significant exception was noted: a statistically significant increase (P value = .0003) in attendances for "chemicals, poisons, and overdoses, including alcohol" and "acute alcohol intoxication" were observed in London EDs coinciding with the timing of the Olympic opening ceremony (9:00 pm July 27, 2012 to 01:00 am July 28, 2012). CONCLUSIONS: Syndromic surveillance was able to provide near to real-time monitoring and could identify hourly changes in patterns of presentation during the London 2012 Olympic Games. Reassurance can be provided to planners of future mass-gathering events that there was no discernible impact in overall attendances to sentinel EDs or GP OOH services in the host country. The increase in attendances for alcohol-related causes during the opening ceremony, however, may provide an opportunity for future public health interventions. Todkill D , Hughes HE , Elliot AJ , Morbey RA , Edeghere O , Harcourt S , Hughes T , Endericks T , McCloskey B , Catchpole M , Ibbotson S , Smith G . An observational study using English syndromic surveillance data collected during the 2012 London Olympics - what did syndromic surveillance show and what can we learn for future mass-gathering events? Prehosp Disaster Med. 2016;31(6):628-634.

Development and refinement of new statistical methods for enhanced syndromic surveillance during the 2012 Olympic and Paralympic Games.

Prior to the 2012 London Olympic and Paralympic Games, new statistical methods had to be developed for the enhanced syndromic surveillance during the Games. Different methods were developed depending on whether or not historical data were available. Practical solutions were needed to cope with the required daily reporting and data quality issues. During the Games, nearly 4800 signals were tested on average each day, generating statistical alarms that were assessed to provide information on areas of potential public health concern and reassurance that no major adverse incident had occurred. GRAPHICAL ABSTRACT: spjhi;21/2/159/FIG41460458213517577 F1 fig4-1460458213517577.