Measles loves mass gatherings: events where thousands of people come together in a crowded space. The disease is spread by an airborne virus and is highly contagious.
The measles virus has long taken advantage of international football tournaments and rock concerts to find new victims who unwittingly take the disease back to their own countries.
A fascinating new article published in the Eurosurveillance journal, looks back at a number of small measles epidemics in Europe in 2011.
The story begins in Rimini, Italy, in early June 2011. Hundreds of participants and thousands of spectators had converged on Rimini for the 16th Italia Super Cup – an international youth football tournament.
After the event, around the middle of June, two Germany footballers living in Baden-Wuerttemberg in Germany began showing symptoms of measles. They had, it would appear, picked up the measles virus in Italy. Neither had been vaccinated against measles.
The first, a 16-year-old, spread the infection to two unvaccinated siblings. The second, an unvaccinated 18-year-old, only began to notice symptoms while attending the Southside Festival – an annual music festival in Neuhausen ob Eck, Germany, attended by 50,000 people.
A week after the music festival, towards the end of June, seven people became ill with measles. One of these passed the virus to two relatives whose symptoms appeared during the first week of July.
The outbreak which began in early June in Italy was continuing in Germany a month later.
Most of those affected in the German outbreak were aged 11 to 27. Measles vaccination rates in Germany rose from 91% in 2000 to 96% in 2010 (for the first dose of MMR).
So, while younger children were not affected thanks to strong vaccine uptake, there is a subgroup of susceptible adolescents and young adults who are at risk because the immunisation rate was lower when they were kids.
Busy week in Rimini
The Italia Super Cup was not the only event in Remini in early June 2011. The World Association of Kickboxing Organisations (WAKE) also held its ‘Bestfigher World Cup Tournament’, drawing 2,100 visitors.
There, an unvaccinated 34-year-old woman living in Slovenia contracted the virus and developed symptoms in mid-June when she got home. She visited a local clinic where it appears the disease spread to staff and some other patients.
The research shows that most of the cases in Slovenia occurred in healthcare and community institutions. The outbreak also affected a member of staff at a local kindergarten.
In the week that followed, 11 of her contacts in Slovenia were diagnosed with measles. Eight of these were in the same town, with the others in different towns ranging from 24km to 62km away. One of those infected passed the disease to his spouse who had a rash and a fever by mid-July.
The Rimini outbreak reminds us of a few important things:
- Measles in a highly-contagious airborne disease
- You can catch the disease and not know it for more than a week
- You can spread measles before symptoms develop
- Measles can cross borders with ease
- Mass gatherings can cause the disease to spread, especially among unvaccinated people