MEASLES

Before immunisation campaigns, measles occurred in
almost 100% of children world-wide. The WHO has set
the objective of eradicating measles globally by 2010,

using the live attenuated vaccine. However, vaccination
of only 70–80% of the population, as is currently
the case in the UK, for example, is insufficient to prevent
outbreaks in older children and adults, who are more
susceptible to complications. Natural illness produces
lifelong immunity.

Clinical features:

Infection is by respiratory droplets with an incubation
period of 6–19 days. A prodromal illness, 1–3 days before
the rash, occurs with upper respiratory symptoms, conjunctivitis
and the presence of Koplik’s spots on the interinternal
buccal mucosa. These small white spots
surrounded by erythema are pathognomonic of measles.
As natural antibody develops, the maculopapular rash
appears, spreading from the face to the extremities.
Generalised lymphadenopathy and diarrhoea
are common, with otitis media and bacterial pneumonia
recognised complications. Clinical encephalitis occurs in
approximately 0.1% of children. A rare late complication is
subacute sclerosing panencephalitis (SSPE), which occurs
up to 7 years after infection.

Diagnosis is clinical (although this is unreliable in areas where measles is no longer common) and by detection of antibody (serum IgM, seroconversion or salivary IgM).

Disease is more severe and prolonged in adults and complications
include pneumonitis, hepatitis and encephalitis. Measles is a serious disease in the malnourished, vitamindeficient or immunocompromised, in whom the typical rash may be missing and persistent infection with a giant cell pneumonitis or encephalitis may occur. In tuberculosis infection, measles suppresses cell-mediated immunity and
may exacerbate disease; for this reason, measles vaccination
should be deferred until after commencing antituberculous
treatment. Measles does not cause congenital malformation
but may be more severe in pregnant women.
Mortality clusters at the extremes of age, averaging
1:1000 in developed countries and up to 1:4 in developing
countries. Death usually results from bacterial superinfection
such as pneumonia, diarrhoeal disease or noma/
cancrum oris.

Management and prevention:

Normal immunoglobulin attenuates the disease in the
immunocompromised (regardless of vaccination status)
and in non-immune pregnant women, but must be given
within 6 days of exposure. Vaccination can be used in
outbreaks and vitamin A may improve the outcome in
uncomplicated disease. Antibiotic therapy is reserved
for bacterial complications.
All children aged 12–15 months (when maternal antibody
will no longer be present) should receive measles
vaccination (as combined measles, mumps and rubella
(MMR), a live attenuated vaccine), and a further MMR
dose at the age of 4 years.

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