The UK health authorities have maintained that the outbreak has been caused by low vaccination levels that resulted from the Andrew Wakefield study that suggested a link between the vaccine and autism.
But the WDDTY survey, which polled around 200 adolescents who have contracted measles in the latest outbreak, discovered that 60 of them had been fully vaccinated at the time. In other words, the vaccine didn't protect them against the disease.
In all, around 1,150 children and adolescents in the South Wales region developed measles.
It's not the first survey to reveal the ineffectiveness of the MMR vaccine. Studies among children in the US who developed measles have discovered that up to 98 per cent of them had been fully vaccinated.