The Health Service Executive has said that there have been further cases of measles after it confirmed two cases in north Dublin last week.
In a statement, it said that there are now seven confirmed cases affecting Dublin and Meath, with most of the cases in Dublin city.
The HSE says that the Measles Outbreak Control Team continues to investigate and advise on measures to control the spread of the illness.
It also said that alerts in relation to measles have been sent to all Emergency Departments and General Practitioners in the affected areas.
The HSE said it is aware that "children with measles have attended various GP surgeries in Meath and Dublin, as well as the Emergency Departments of some Dublin Paediatric Hospitals while they were infectious.
They said: "As a result of this, there is an increased risk of exposure to measles among people who attended such healthcare services from Thursday 19 October 2017, onwards.
"As measles is now circulating in the community, it is important that everyone be aware of the possible risk of spread whenever groups of people gather."
The HSE said the best protection against measles is to be fully vaccinated with two doses of the MMR (Measles-Mumps-Rubella) vaccine.
Those most at risk of catching measles are those who are not fully vaccinated with two doses of the MMR vaccine, such as babies younger than 12 months who are too young to be vaccinated, and those with weakened immune systems.
The HSE has advised that if people have symptoms suggestive of measles, they should stay at home, not go to school, or work and phone their GP.