The Lancet has published a Series of reports about different mass gatherings: the London 2012 Olympic and Paralympic Games; the 2012 European Football Championship finals (Euro 2012), hosted jointly by Poland and Ukraine; and Hajj 2012 and Hajj 2013. These reports, led by Professor Ziad Memish, Deputy Minister of Health for Public Health in Saudi Arabia, and Professor Alimuddin Zumla, at University College London Medical School, UK, set out the planning and surveillance systems used to monitor public health risks, and describe the public health experiences and lessons learnt for the planning of future events.

Boosting pilgrims' safety with the latest electronic disease surveillance at the Hajj

In this Review, Professor Ziad Memish, Deputy Minister of Health for Public Health in Saudi Arabia and colleagues outline the latest real-time disease surveillance system that was recently piloted to successfully monitor and assess public health risks among the 5 million pilgrims from 184 countries during the Hajj 2012 and Hajj 2013.

The health-care web-based electronic surveillance system was introduced in 2012 to help officials respond more quickly and effectively to potential infectious disease threats. Hospitals, clinics, and medical centres in Mina, Arafat, and Muzdalifah that provide free medical care during the Hajj were able to rapidly relay demographic and health data to the operations centre in Makkah to guide further investigation and intervention. The new technology was successfully put to the test after MERS coronavirus was first discovered in September 2012. No cases of MERS infection were reported during the Hajj in 2012 and 2013.

According to Professor Memish, "After decades of managing millions of pilgrims who undertake the Hajj, Saudi Arabia is at the forefront of expertise in providing surveillance and health care during mass gatherings, and in 2012 established the Global Center for Mass Gatherings Medicine. This centre is a virtual research network of academic and public health institutions from around the world who will conduct studies to develop optimum recommendations for the prevention, management, and control of infectious diseases for countries that host mass gatherings, and to help strengthen global health security."*

Biggest public health challenge at London 2012 Olympics was reassuring politicians and the media that there were no health threats

In this Review, researchers led by Dr Brian McCloskey, who coordinated the Health Protection Agency's seven year preparations for the London 2012 Olympic Games, report that although no major public health incidents arose during the Games, the biggest challenge was reassuring the organising committee, government, media, and the public that there were no health-protection concerns.

The authors point out that although the overall risk of public health problems, including infectious disease outbreaks, at large-scale international sporting events is small, public health surveillance and response systems need to be ready to detect and respond much quicker than normal. In addition, the need for reassurance about the absence of such threats is much greater than previously thought and could challenge traditional health surveillance systems. They call for enhancements to surveillance and reporting systems to be made a key part of public health planning for future sporting events like the upcoming 2014 FIFA World Cup in Brazil.

According to Dr McCloskey, "Demand for information about any possible risk to the Games and to the reputation of the host country is huge. Politicians and decision makers often seek reassurance that nothing is happening - this negative finding is not easily and reliably obtained from routine surveillance systems because they are not primarily designed to prove that nothing is happening. So these systems need to be reviewed and enhanced to fulfil this role effectively. The good thing is that these enhanced systems are then a positive legacy for the host country."*

Lessons learnt from the management of Euro 2012 could help build health legacies for future sporting events

In this Review, Dr Catherine Smallwood and Dr Maurizio Barbeschi of WHO, Geneva, Switzerland and colleagues outline the ways in which organisers of future sporting mass gatherings can, and should, learn from the management of the safety and wellbeing of more than eight million people at the Euro 2012 Football Championships in Poland and Ukraine.

According to Dr Smallwood and Dr Maurizio Barbeschi, "Organisers of mass gatherings should make every effort to share their experiences - through the WHO Network of Collaborating Centres on Mass Gatherings, the International Observer Program and other means - so that organisers of future mass gatherings can plan as best as possible. More work needs to be done to document the legacy of mass gatherings, and frameworks should be developed to include health legacy in the planning of these events."*