Sunday, August 5, 2012

Record measles outbreak in UK's Merseyside hits un- and undervaccinated

it is another bad year for measles - following on the European measles record year 2011, which saw, from January to October, 26'000 cases, with 9 deaths and nearly 7300 hospitalisation, measles are still going strong in UK. Various regions are reporting outbreaks, Wales saw over 100 cases in Gwynedd and Porthmadog. Sussex has seen just over 300 cases of measles this year. The area worst hit is Merseyside, a small county in England's North West, with a population just under 1.4 million. After a single measles case was seen in January, case numbers slowly increased to nearly 360 confirmed and over 150 suspected cases by the end of June. Luckily, there has not been a death so far, but 18% of the confirmed cases had to be hospitalised. Contrary to rumours circulating on the internet, the outbreak was not mostly in fully vaccinated children (it is interesting how pertussis and measles myths and facts mix and make for new vaccine-sceptical tales). The HPA team have now published the break down of measles numbers in this outbreak and of the proportion of vaccinated and unvaccinated patients. Indeed, only 12 of the 359 confirmed cases (3.3%) have had two MMRs*. The associated figure is very telling:

Take a good look at this. All orange and dark blue are unvaccinated, all green and purple are just vaccinated once (the UK recommends the first MMR at 13 months, the second at 41, so all green children were vaccinated age-appropriately only once). Only the light blue had 2x MMR. You may have to search for that stripe a bit, it is quite small. This is particularly interesting, since Merseyside has quite a high vaccine uptake, with 96% of children in Liverpool having had their first MMR. Consequently, the characteristics of this outbreak are very different from one in a largely unvaccinated population (like for example the 2008 outbreak in Salzburg, where 202 cases occurred in a month, largely in a 300 pupil Steiner school with 20% vaccine coverage), propagation of the measles is slow, with cases infecting very few other people. While it is a bit discouraging that the high vaccination coverage amongst young children has not stopped the outbreak entirely, it is clear what can be done.

Coverage for the second MMR needs to be increased. Older pupils, students and adults should check their vaccination records to ensure that they really have had two MMRs, children older than 13 and younger than 41 months could get their second MMR early during an outbreak to reduce the risk.

Consider getting your infant (between 6 and 12 months) vaccinated, if s/he is at "higher risk" (daycare) and there is an outbreak in the area - almost a quarter of cases in this outbreak were in the under one-year-olds, who are at particularly high risk of complications.
Anyone who intends to work/volunteer in the medical sector should have had two MMRs. In this, as in nearly every recent outbreak, transmissions within the medical setting and to medical personnel occurred.

Doctors and nurses need to familiarise themselves with the symptoms of measles, so that they can diagnose them early and limit transmission in the medical setting.

And finally, all parents need to think long and hard before taking their child into A&E or their GP's practice whether their child could be contagious, especially if the child has not had their MMRs and could be carrying a potentially fatal disease. Call ahead, get an "out of hours" appointment or home visit, if at all possible.

* Footnote: instead of complaining about vague language in HPA reports and speculating about the number of fully vaccinated children in this outbreak, people could have just emailed/called the HPA. They do have a presence on Facebook, too and are quite happy to answer any question in depth (I have talked to them through FB, email and phone).

1 comment:

  1. Measles outbreak case

    On 15 March 2010, a case of measles was reported to the District Health Office in Essen.

    In total 71 cases occurred from 15 March to 19 May (four cases hospitalised), with the majority linked to a Waldorf school.

    Only one case had been vaccinated twice, two cases had been vaccinated once.

    Immediate and consequent exclusion of non-immune children from classes for two weeks as well as the adjacent spring break prevented the wider spread of the virus.