Mass gatherings can be accompanied by a number of health risks – especially the increase in population density, the import and export of unusual pathogens, and temporary changes in services like provisional food stalls, all of which can increase the possibility for infectious disease spread . As a result, public health authorities have begun to develop strategies for prevention and response. For example, they enhance routine surveillance and/or introduce additional syndromic surveillance during mass gatherings to timely detect and react on adverse health events [2–6]. The following parameters may influence the appropriate level of enhanced surveillance for mass gatherings: (a) number of participants, (b) duration of the event, (c) its spatial distribution, (d) origin of participants, (e) level of infectious disease activity in the host country, and (f) amount of public attention.
Recent consensus prescribes that enhanced surveillance systems should be in place for big-scale international mass gatherings, and they have been routinely implemented during the past years. Most previously published descriptions of enhanced surveillance concern recurring large-scale mass gatherings like the annual pilgrimage to Mecca , or sport events like the Olympics or FIFA Men’s World Cups [1, 3–5, 7–13]. As these mass events are usually predictable in dimension, structure, and amount of public attention, publications on experiences with the implemented surveillance measures can be of great assistance for new host countries to set up surveillance for their event. However, deciding on an adequate surveillance strategy for a medium-scale mass event can be difficult if (a) an event is new, (b) one or more of the influencing parameters are unclear or differ greatly to previous occasions, and (c) no prior experience with similar events is available.
For 2011, Germany was chosen to host the 6th FIFA Women’s World Cup. Even though men’s football is the most popular sport in Germany, it was unclear to what extend the Women’s World Cup would benefit from the men’s sports popularity in terms of number of tickets sold and visitors attending public fan festivals. Publications on surveillance concepts during previous FIFA Women’s World Cups were not available, but it was documented that the tournaments had fluctuated considerably in size (115.000 - 1.2 million tickets sold) over the past years .
Since 2001, Germany has a well functioning routine electronic reporting system for notifiable infectious diseases (called “SurvNet” - developed by the Robert Koch Institute (RKI) - and a number of comparable commercial software products) [15, 16] that transmits surveillance data from the >350 district health authorities via the corresponding 16 federal state authorities to the RKI, the National Public Health Institute. The German Infection Protection Act from 2001 determines which infectious diseases are notifiable by physicians and laboratories to the district health authorities . Notifications of cases and outbreaks are weekly transmitted from the district health authorities to the state health authorities and on to the RKI. For a small number of pathogens, e.g. imported diseases like malaria with no potential for further local transmission, laboratories and/or physicians transmit notifications directly to the RKI. In general, responsibility for surveillance and containment actions solely lies with the district health authorities.
Six months prior to the Women’s World Cup in Germany, only limited specific information on the tournament was available: the games were to take place over 3 weeks from June 26 to July 17; a total of 16 teams had qualified, 10 coming from developed countries (Germany, England, France, Norway, Sweden, Australia, New Zealand, Canada, United States, and Japan) and 6 from developing countries (Equatorial Guinea, Nigeria, North Korea, Brazil, Columbia, and Mexico); games were to be carried out in 9 cities (located in 7 of the 16 federal states) all over Germany ; and approximately 900,000 tickets were going into public sale . However, ticket sales remained slow in the pre-phase of the event and public attention was low to moderate.
Five years prior to the FIFA Women’s World Cup, Germany had hosted the men’s competition, which had taken place in 12 cities over a time period of 4 weeks with a total of 32 teams from 6 continents. Around 3 million stadium tickets had been sold, and another estimated 21 million people attended public viewing sites and fan festivals . For the event, health authorities enhanced the pre-existing surveillance system by e.g. acceleration of data transmission and introduction of an additional free-text reporting system for relevant public health events; additional syndromic surveillance was not introduced. The chosen strategy hereby proved to be an effective approach [1, 5, 20].
Positive experiences with enhanced surveillance during the Men’s Cup led to the decision to likewise enhance surveillance without a syndromic component for the Women’s Cup. As the women’s event was—in comparison to many aspects—anticipated to be considerably smaller, we deemed re-implementation of the enhanced surveillance measures from the Men’s Cup as inappropriate and thus needed to newly determine an adequate event-specific surveillance level. We therefore aimed to introduce an approach for tailoring an adequate enhanced surveillance for smaller-scale mass gatherings, using the example of the FIFA Women’s World Cup 2011 in Germany.