Although mass gatherings (MGs) have the potential to amplify and accelerate the spread of infectious disease across the world, they also provide unique opportunities to promote public health action such as vaccination that can lessen the risks for the host communities and benefit the countries to which participants return, according to the second paper in The Lancet Infectious Diseases Series on mass gatherings health.
In this paper, an international team of experts led by Ibrahim Abubakar, Professor of Infectious Disease Epidemiology at the University of East Anglia, Norwich, UK, and head of the TB section at the Health Protection Agency, London, UK, analyse the risk of infectious diseases at MGs and discuss the increasing importance of the control of infectious diseases in the planning of MGs.
They observe that overcrowding and poor planning can make large-scale events a potential breeding ground and reservoir for infectious diseases, whilst international travel to and from such gatherings create unrivalled opportunities for the spread of infections all over the world.
Influenza is one of the most common illnesses identified in travellers and the close proximity of people at MGs further increases the risk of transmission and the potential of a pandemic arising from such an event. In 2008, an influenza outbreak at the World Youth Day in Sydney, Australia, spread rapidly as a result of overcrowded accommodation and low rates of vaccination. The following year, individuals attending music festivals in Belgium, Serbia, and Hungary were diagnosed with the pandemic strain of influenza H1N1.
The authors report that the introduction of control measures including awareness campaigns, better surveillance, and respiratory hygiene recommendations were successful at preventing outbreaks of influenza H1N1 during the global pandemic in 2009 at the Hajj and the Asian Youth Games in Singapore.
The importance of planning and effective public health action to prevent the introduction and transmission of non-endemic diseases during and after MGs was shown by the 2007 Cricket World Cup, which was attended by teams and supporters from countries around the Indian Ocean that were experiencing a large outbreak of chikungunya. Measures including enhanced surveillance, practical advice to reduce mosquito bites, and immunisation prevented outbreaks in returning supporters of chikungunya and diseases that were endemic in some of the Caribbean host countries, including malaria, dengue, and yellow fever.
Abubakar and colleagues say that key to the prevention of infectious disease at MGs is coordinated risk assessment and management before, during, and after the event.
Moreover, they suggest that MGs provide unique opportunities to communicate public health information and could speed up the development of interventions to reduce the transmission of infectious diseases. For instance, in sub-Saharan-Africa there is a strong incentive to promote some vaccinations in response to outbreaks of infectious diseases during the Hajj.
They conclude: "Essential to the management of health threats is the need for cooperation between national, regional, and international partners, especially for surveillance after an event. MGs provide an untapped opportunity for host countries to promote global health diplomacy and to model ideal public health behaviours."
Professor Ibrahim Abubakar, University of East Anglia, Norwich UK and Health Protection Agency, London, UK. Via Georgina Fletcher, HPA Press Office T) +44 (0)20 8327 6690 or +44 (0)20 8327 7901
Or Annie Ogden, University of East Anglia Communications Department T) +44(0)1603 592764