Measles is a highly infectious disease that can cause serious complications, particularly in children under one year of age, pregnant women and the immuno-suppressed.

It typically starts with cold-like symptoms that develop about 10 days after a person gets infected. The person will get a rash a few days later.

The illness usually lasts for seven to 10 days.

• Cold-like symptoms such as aches and pains, a runny nose, sneezing and a cough
• Sore, red eyes that may be sensitive to light
• A temperature of 38 degrees Celsius or above (fever), which may reach around 40 degrees Celsius
• Small greyish-white spots in your mouth
• Loss of appetite
• Tiredness, irritability and a general lack of energy

Many people with measles develop small greyish-white spots in their mouths. These appear before the rash and usually last for a few days. A rash appears around two to four days after the first symptoms and fades after about a week.

If you have these symptoms, you should seek medical advice. People are advised to phone prior to attending their GP, Emergency Department or other healthcare provider to inform them they have these symptoms.

To reduce the risk of spreading the infection to others, people should avoid:

• work, school or childcare for at least four days after they developed the measles rash
• contact with young children and pregnant women

If 1,000 people get measles:

• one or two will die
• 50 will get an ear infection
• 40 will get pneumonia or bronchitis
• five will have convulsions (fits)
• 160 will get diarrhoea

Typically, one in 1,000 people will develop encephalitis (swelling of the brain). For every 10 children who develop encephalitis, one will die and up to four will have brain damage.

One in 8,000 children under two years of age get SSPE (brain degeneration), which may be many years after measles and is always fatal.

One in 6,000 people will get a blood clotting problem.

The MMR (measles, mumps and rubella) vaccination is the best way to protect people from measles.

Two doses of the MMR vaccine are necessary to be considered fully vaccinated. The first dose is given by a GP when a child is 12 months of age. The second dose is generally given by school vaccination teams when the child is in junior infants.

If a person is unsure if they or their child has received one or both doses of the MMR vaccine, they should contact their GP. A person can also request their vaccine records from the HSE.

An MMR catch-up programme was launched through GP centres in November 2023, aimed at children and young adults who did not receive one or both doses of the vaccine. Some GPs are also offering MMR boosters to older adults. A person should contact their GP for more information.

The HSE runs information campaigns targeting migrants who may not have received the MMR vaccine (in a number of languages), as well as members of the Travelling and Roma communities.

The overall uptake of the MMR vaccine in Ireland in 2021/2022, the latest figures available, was 87.5%. The uptake rates ranged from 74.1% in Dublin North Central to 97.2% in Dublin South East.

The WHO recommends a 95% uptake rate of the MMR vaccine to ensure herd immunity. Some people cannot be vaccinated – for health reasons, pregnancy, or if they are less than one year old – and rely on mass immunity among the general population.

“The importance of taking precautions to protect both the individual and the community from measles cannot be understated,” a spokesperson from the HSE told The Journal.

“While measles is preventable through vaccination, the virus spreads very quickly between people who are not vaccinated and can have severe consequences, particularly for babies and vulnerable groups.”

A recent Irish study estimated that almost one-in-five males aged 18 and 19 are unvaccinated against measles.

A HSE spokesperson said some parents are or were hesitant to vaccinate their children “due to concerns about vaccine safety, often fuelled by misinformation”.

One of the reasons some people are reluctant to vaccinate their children is because of a now widely discredited study from the late 1990s. British doctor Andrew Wakefield published a study in the Lancet medical journal in 1998 that linked the MMR vaccine to autism.

However, the findings were later disproved. In 2010, the study was retracted and Wakefield was struck off the medical register in the UK.

In the past 30 years, more than 500 million doses of MMR vaccine have been given in over 90 countries.

“Experts from around the world, including the World Health Organisation, agree that there is no link between the MMR vaccine and autism,” the HSE’s spokesperson said.

“Numerous studies have proved that the vaccine is safe, however the misinformation may continue to circulate and can influence vaccine decisions.”

A decline in uptake rates may also be partially due to complacency. There have been relatively few measles cases in Ireland in recent years because of the success of the MMR vaccine.

Due to the fact cases are rare, some people “underestimate the severity” of measles and choose not to get vaccinated or vaccinate their child, the spokesperson added.