Move use of your practice computer into 21st century
Swift action by GPs may be needed to contain measles outbreaks Dr David Elliman and Dr Helen Bedford advise on contingency plansx
GPs may be needed to contain measles outbreaks
Dr David Elliman and Dr Helen Bedford advise on contingency plansx
A measles epidemic in which one in 10 infected children requires hospital treatment is now a possibility if MMR uptake remains low, according to the Health Protection Agency. In the past five years there have been large outbreaks in Dublin, Italy and the Netherlands, all resulting in deaths in children, most of them previously well. Large numbers of complications have also been reported, including convulsions and pneumonia.
In the Dublin outbreak of 2002, there were 1,115 notified cases, 111 hospital admissions and three deaths1.
Ironically, it is infants too young to receive MMR who are most at risk of the late onset complication, subacute sclerosing panencephalitis (SSPE).
The risk is 16 times higher among children who contract the disease under the age of one year compared with over five years.
These children, together with others for whom the vaccine is contraindicated, depend on high levels of herd immunity for their protection.
Mortality and morbidity, in general, are also age dependent with higher rates of complications in babies and older adolescents and adults2.
Effects of the fall in uptake
of MMR vaccine
After initial very good rates of immunisation, over the past nine years there has been a significant decline in MMR uptake with rates falling from 92 per cent at two years old in 1995/6 to 80 per cent in 2002/3.
This appears to be largely due to parents' concerns over the safety of the vaccine. An unknown proportion of those children who have not had MMR will have had one or more separate vaccines, but the quality of the vaccines has been variable. Although uptake nationally is improving slightly, in London it remains unacceptably low and ranges from 53 per cent to 86 per cent.
In primary school-age children, the younger the child, the less likely they will be to have received two doses of vaccine.
Risk of an epidemic or
Knowing the uptake of a vaccine, how infectious the disease is and how much population mixing there is, makes it possible to predict the level of immunisation
below which outbreaks are likely. Jansen et al have shown that the current levels of MMR uptake are such that outbreaks are to be expected4.
Indeed we have seen such outbreaks in south London and there is a trend for these to get bigger.
As the risk of a measles outbreak happening is now high, it is important that PCTs and GPs have a contingency plan. The most important part of any such plan has to be timely, accurate diagnosis and notification.
Measles usually begins with a fever, cough, coryza and conjunctivitis. A day or two later Koplik spots may be seen.
After a further one or two days, a maculopapular rash appears, starting at the hairline and spreading down over the body, and the child is usually very miserable.
Three to four days on from this the rash fades. However, there are many other viral infections that have a similar picture and, as measles is now uncommon, most such presentations are not measles. Any clinically suspected case of measles should be notified immediately. The doctor would then be asked to collect a saliva sample to confirm or refute the diagnosis.
Managing cases and contacts
There is no specific treatment for measles other than the management of symptoms. However, if a secondary pneumonia develops antibiotics may be appropriate and, if there is significant central nervous involvement, hospital admission may be indicated.
If a child is in contact with a case of measles, MMR vaccine given within three days will significantly reduce the chances of developing the disease.
Immunoglobulin is indicated for children and adults who are not immune, cannot be immunised and are at high risk of severe disease, such as those who are immuno-suppressed.
Immunoglobin is also worth considering for pregnant women and infants six-eight months old or younger if the mother has not had measles or is uncertain whether she has.
Under these circumstances, advice should be sought from the local consultant in communicable disease control. Ideally, immunoglobulin should be given within 72 hours of contact, but even up to six days after, it is worth administering3.
Control of the disease is partly by isolation until the period of infectivity has passed (from two days before the development of the rash to five days after), and by ensuring that all potential contacts have been immunised.
Controlling spread in the
The best method of control is ensuring all children have two doses of MMR. In an outbreak the standard schedule may need to be altered in a number of ways. The current advice in UK is that the first dose of MMR is given after the first birthday. In an outbreak this can be brought forward to nine months.
This provides immunity to those babies who do not have maternal antibodies. But this early dose should be given in addition to the routine course rather than as a substitute for the first dose.
It is worth noting that the second dose is
not a booster but is given to immunise those who did not respond to the first dose, at the same time as the preschool booster of DTaP/IPV.
Children who start the course later than this can be given two doses as soon as possible as long as three months elapse between them.
In an outbreak, a child aged over one year can have the second dose of MMR early so that there is a gap of one month between doses.
The London campaign
Because the uptake rates in London are particularly low, a campaign targeting children in primary school has been launched.
The details will vary between PCTs, but in most areas, children in primary school who have not had two doses of MMR will be offered a single dose in school.
Those who need another dose will be advised to have this at their GP four weeks later5.
Likely effect of measles outbreak
on public opinion of MMR
It is difficult to predict what the response to an outbreak of measles might be. Some parents who are wavering might decide to go for the MMR vaccine.
Others, who had decided on the single vaccines, may simply become more entrenched and apply moral blackmail to the Government, saying it is the absence of single vaccines that is putting their children at risk whereas it is of course their decision not to have the MMR that is the problem. Professionals should resist this.
Because of the previous high uptake of MMR vaccine, measles was becoming uncommon. The fall in uptake more recently has resulted in an increase in measles cases. Uptake is now so low that outbreaks are almost inevitable.
It is important to take every opportunity to immunise children fully. When cases of measles are reported, this becomes particularly important.
It would be tragic if this highly preventable disease returned and children died as a result.
How real is the threat?
HPA modelling indicates that
The level of unvaccinated children in London has reached the point where measles transmission can be sustained, so that an epidemic is a possibility
Around one in 10 children infected would require hospitalisation
If MMR uptake remains low in the rest of the country, then the same risk could eventually arise~
Health Protection Agency October 2004
·At the Department of Health immunisation website there is information for parents and professionals on all vaccines, including MMR. There is also a copy of the London Catch-up Campaign leaflet for parents. www.immunisation.nhs.uk
·The Health Protection Agency website has details of immunisation uptake and incidence of vaccine preventable diseases. www.hpa.org.uk/infections/default.htm
1 McBrien J et al. Measles outbreak in Dublin, 2000.
Pediatr Infect Dis J, 2003;22:580-4
2 Anon. Current Trends Measles United States, 1990.
3 Health Protection Agency. Immunoglobulin Handbook. www.hpa.org.uk/infections/topics_az/immunoglobulin/menu.htm
4 Jansen VAA et al. Measles Outbreaks in a Population with Declining Vaccine Uptake. Science 2003;301:804
5 MMR capital catch-up campaign. www.immunisation.nhs.uk/files/capitalcatchup_leaflet.pdf
David Elliman is consultant in community child health at Great Ormond Street Hospital for Children, London
Helen Bedford is lecturer
in children's health at the Institute of Child Health, London