Medical matters: Vaccine holds the key to making measles a thing of the past

In the infamous words of Gerry Adams from some years back, "It hasn't gone away you know." I'm referring to measles rather than a paramilitary organisation, but the phrase is appropriate as measles continues to stage a comeback across the world.

South Wales is the latest area in these islands to face a major outbreak of the viral illness, which has affected over 800 people in the region, 77 of whom needed hospitalisation. In the north of England there have been 354 cases of measles in 2013 so far.

And the pool of vulnerable children in the UK is worrying; some 8 per cent of those aged 10-16 years have had no measles, mumps and rubella (MMR) vaccine, and 8 per cent have had only one of the required two doses.

Increase in cases
Across the Atlantic, in Canada, while the numbers are smaller, the percentage increase in cases this year is marked: in four months Toronto has seen seven cases of measles compared with a recent full-year average of five people diagnosed with the infection.

If vaccination rates for measles drop by just 10 per cent, Toronto could expect large outbreaks of up to 10,000 cases in as few as five years, Canadian public health experts say.

They are used to such small numbers because measles was once thought to be near eradication in the Americas due to the effectiveness of mass vaccination programmes introduced in the 1970s.

The worldwide resurgence in the infectious disease is because of parental concerns about a suggested link between the MMR vaccine and autism. MMR immunisation rates have still not recovered following now discredited research by Andrew Wakefield in 1998 linking the vaccine with bowel disease and autism.

Highly infectious
Measles is a highly infectious disease. If you haven't been vaccinated and are exposed to the virus you have a 90 per cent chance of acquiring the infection.

It spreads through droplets in the air from coughing or sneezing, and has an incubation period of about 10 days.

Symptoms then develop, starting with irritability, a runny nose, red eyes, a hacking cough and a fever. These symptoms may last up to eight days.

A skin rash, consisting of flat red or brown blotches, starts from day four. It usually starts on the forehead and spreads downwards over the face, neck and body and lasts from four to seven days.

About one in 20 of those infected will get pneumonia, one in 1,000 will get encephalitis (brain inflammation) and between one and two in 1,000 will die from measles.

Vaccine exposure
The good news is that MMR given to a child within 72 hours of exposure to measles may prevent the illness.

The vaccine can prevent measles in more than 90 per cent of immunised children, following a single dose of the vaccine.

With a second dose of MMR vaccine, more than 99 per cent of immunised children are protected from measles infection.

This vaccine is given free by family doctors to children aged 12-15 months, and a second dose is given at school entry. MMR vaccination is also recommended for children aged 11-12 years who have not received two previous doses of MMR.

If a child develops measles, parents should keep unvaccinated siblings out of school or childcare during the incubation period (usually about 14 days but may be up to 21 days), to ensure that they do not transmit infection to other children.

And given the relatively low levels of vaccine coverage across parts of Europe, one of the most important parts of preparing for this year's summer holiday will be for parents to ensure their children are up to date with their MMR shots.

Many older adults will remember measles as a natural part of childhood.

But a question that needs to be faced by today’s parents is how acceptable is it to tolerate any serious complication, or death, from a disease for which an effective vaccine is available?

mhouston@irishtimes.com
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