It’s the season of crowds. We’ve had the World Cup, the Commonwealth Games and countless music festivals. Our airports are heaving. There’s a plethora of diseases you might catch from such proximity – so, should you worry? Astonishingly, almost certainly not. And that is thanks to mass surveillance.
For instance, we now have a report on the effectiveness of health surveillance at the London 2012 Olympic Games. The event threw 11 million people from 205 nations into close contact. Objectively, it looks like a public health nightmare – yet it wasn’t.
In fact, we might have predicted that from the entirely dull health records of previous Olympic gatherings. At Atlanta 1996 and Sydney 2000, less than 1 per cent of the visits to health-care professionals were due to infectious diseases. Athens 2004 had no reports of infectious disease outbreaks and the communicable disease reports from Beijing 2008 were down 40 per cent on those for the city in 2007.
London 2012 followed the pattern. As with previous Olympics, its safety can be ascribed to years of planning, with protocols established for the daily reporting of any threat of a virulent infectious disease. Intensive-care units were given access to websites for alerting public health authorities to suspicious cases.
The precautions included daily assessments of the worldwide threat of new infectious diseases and how these might travel to London. That is how we know that a few teams suffered norovirus outbreaks before they arrived, and that there was an outbreak of chicken pox among staff at one of the Olympic hotels. All threats were safely contained. During the event, there were a few cases of gastrointestinal infections but little more. In the end, nothing occurred that would not happen in the average UK summer.
Not every mass gathering benefits from Olympic-style planning. Music festivals are particularly prone to problems. There have been outbreaks of Campylobacter infection at Glastonbury and of H1N1 at festivals in Belgium, Hungary and Serbia. That is why some researchers are calling for better surveillance of the threats to festival-goers’ health.
A comprehensive survey of 32 years of medical reports from large-scale music festivals shows that they are generally low-risk events, but this does vary. Reports of gastrointestinal problems range from nine per 100,000 people at Glastonbury 1997 to 55,000 per 100,000 at the 1987 meeting of the Rainbow Family in North Carolina. When over half the people at your chosen event contract dysentery, you know you’ve picked badly.
Music festivals are also hot spots for occasional breakouts of measles and mumps. That is partly because there is a higher incidence of vaccine-shunning among the segments of the population likely to attend music festivals. Some health researchers are recommending that festivals implement a rule similar to the one in place for Hajj pilgrims, who have to present a complete immunisation record; or at least offer on-site vaccinations.
Judicious use of social media might also help. A collaboration between British, Israeli and Danish researchers correlated 7.5 million tweets and 32,000 online health searches to link disease outbreaks with specific festival gatherings. It wouldn’t be hard, they pointed out, to use Twitter or Facebook to follow up visitors at a festival that has created particular health problems. Festival-goers might benefit from messages with advice about their likely exposure, symptoms to look out for and whether to seek a medical consultation. Mass surveillance doesn’t always have to be used for evil.