At a time when health officials are quietly admitting that there could be a link between the MMR (measles-mumps-rubella) vaccine and autism, a new study has also discovered that it doesn't work.
Researchers investigating a large outbreak of mumps in 2006, when 6,584 cases were reported among college students, have discovered that virtually every sufferer had been vaccinated twice against the disease.
The Centers for Disease Control (CDC) reveals that at least 84 per cent of young adults aged between 18 and 24 years had received two-dose vaccines against mumps. And in 2006 - when the outbreak occurred - the national two-dose coverage among adolescents reached 87 per cent, the highest in US history, and just one point below that needed for 'herd immunity'.
CDC researchers speculate that the outbreak - primarily among 18- to 24-year-olds - was the result of the 'wrong type of mumps'. The vaccine is supposed to protect against A-virus mumps, whereas the outbreak in 2006 was caused by the G-virus strain.
Despite its limitations, the CDC team reckons that all children need a third dose of MMR - even though the two-dose vaccine was introduced following a 1980 mumps outbreak among children who had received a single vaccine dose.
It may be a measure that will be hard to introduce at a time when health officials are accepting that the MMR vaccine can cause autism among children with a 'mitochondrial disorder'.
(Source: New England Journal of Medicine, 2008; 358: 1580-9).