MMR vaccination post-measles exposure may not prevent infection spread
Giving the MMR vaccine to unvaccinated children who have been exposed to the measles virus may not prevent the spread of infection, the Health Protection Agency has warned.
Dr Mary Ramsay, deputy head of the agency's immunisation division, said the evidence suggested vaccinating children after they have
been exposed to measles might not work even if the vaccine was given very early on after exposure.
Dr Ramsay, a consultant epidemiologist, said an outbreak of measles in south London an area with one of the
worst rates of MMR uptake was not successfully contained by giving children MMR post-exposure.
Six children who had been playing with a 17-month-old boy, who was subsequently diagnosed with measles, were offered the MMR vaccine after public health officials discovered none of them had previously had the jab.
Four of the children had the vaccine immediately but they all developed initial symptoms of measles eight days after the first exposure and subsequently developed a typical rash, she said in The Lancet.
Current guidelines recommend MMR should be given within three days of measles exposure to any child who has not been immunised.
But Dr Ramsay said: 'The only reliable way to prevent measles is to maintain high MMR uptake rates in the community.'