Listening to the news reports surrounding the current measles epidemic in South Wales this week, it has struck me afresh how much our nation is in need of a refresher course on the nature of this age-old infection. While it has been one of the resounding successes of modern medicine that this potentially devastating disease is so rare in the developed world in the 21st century, this inevitably means that we have lost a great deal of the collective knowledge and understanding that was such a valuable resource when measles was commonplace. The contrast with chicken pox is clear – we still know this illness and understand it. Parents usually diagnose it themselves and manage it without needing any medical advice, only turning to a doctor when there seem to be problems. For measles, most of us know it involves a fever and a rash, and can be serious, but not much more.
The result of this is that we are left collectively stunned by the death of a man of 25 with measles. How can that happen? Isn’t a young man of that age supposed to be in the prime of his life, having escaped the frailties of childhood but well before the vulnerability of old age? And yet the risk of death as a complication from measles in this age group is the same as that for the under 5’s. In fact the age group that is most at risk of the major complication of measles – death, encephalitis (infection of the brain), hospitalisation and pneumonia – are the over 30’s. Young children are more at risk only for diarrhoea and ear infections.
It is no surprise, therefore, that a woman being interviewed on the radio recently had made the assumption that measles was only really a problem for the under 5’s. Why would she think differently? This is the case for other infections, after all. Whooping cough, for instance, will give you a nasty cough for 3 months as an adult, but it is infants whose life could be in danger. Haemophilus B, part of the vaccination programme for babies, can cause meningitis in the under 2’s, but not in older children. Yet if we assume measles is not a problem for older children and adults, then the greatest risk to a successful catch-up programme for the MMR vaccine is not those ideologically opposed to vaccination, but ignorance and complacency among those with a more moderate view, but who were caught up in the confusion surrounding MMR in the late 1990’s.
It is easy to see why measles is so associated with childhood in our collective unconscious. The disease is so infectious that, before vaccination, it was rare to get to the age of 5 without having succumbed to it – and so our image of the infected patient is usually one of a child. The vaccination programme is delivered in two doses, at around 1 year of age and again pre-school – so we have no reason to associate it with any other age range. The fact that 10-18 year-olds are the primary age group affected by the outbreak in Wales, however, is a stark reminder of the naivety of these assumptions, as it is clear that this infection is no respecter of age, and anyone who lacks immunity is vulnerable.
The post-mortem of the young man who died has been described as inconclusive – there is no doubt that he had measles, but at the moment it cannot be said with certainty that this was the cause of his death. Well, it seems to me that it stretches to incredulity the idea that someone who dies with measles has not died from measles. I suspect we are making another false assumption about his death, however. The fact that he was found dead in his flat could easily make us draw the conclusion that if only he had sought medical advice, he might still be alive now. In truth it is unlikely that a hospital would have been able to do anything. We have better supportive measures these days than in the past, but there is still no treatment at all for measles encephalitis – it always has been, and remains, a lottery – the risks are low (1 in 1000 cases overall, 3 in 1000 for the over 30’s), but the stakes are devastatingly high.
Public Health England are absolutely right to launch a vaccination catch-up campaign across the country rather than just in South Wales. It would be tragic indeed if we waited for an epidemic to break out locally before anything was done, and there are many areas in the country where the drama of what has happened in Swansea could be re-enacted at any time. There is no reason to wait to hear from someone about this either – if you or your child are not fully protected (by either a clear history of having had measles, or two MMR vaccinations) then you can go to your GP this week and ask to be vaccinated. There is no upper age limit. There is also the interesting phenomenon that the children who may have missed out on MMR when they were younger are getting to an age where they can, and should, express their own views and may wish to contact their GP for advice themselves.
A final word about the situation for younger babies, which is a little more complicated. Under 6 months the MMR vaccine is not licensed, and should not be given. These babies also have a great deal of residual immunity from their mothers and so are not at great risk. Over 6 months the vaccine could be given if there was felt to be a significant risk – for instance if someone was planning to visit South Wales. This would be based on parental preference, and is not a clear recommendation. The problem with vaccinating earlier than the usual schedule is that the maternal immunity can neutralise the effects of the vaccine, and so any MMR given early does not ‘count’ towards the schedule and 2 further doses will still be required. For the most part it is best to wait and undergo the usual vaccination programme schedule.