Since July, there have been 13 measles cases in adults and children in North Dublin’s inner city.
An outbreak of measles has been reported in Dublin city, according to the HSE.
The Department of Public Health East said transmission of the disease occurred in hospitals in Dublin and in households with what it described as "poor vaccine uptake".
Measles is highly contagious and spreads easily.
The time between exposure to measles and developing the rash is usually 14 days, with a range of 7 - 21 days. People are infectious from four days before the rash starts until four days after.
According to the HSE, a number of cases have been reported in the wider inner city community. There have been no deaths from measles associated with this outbreak to date.
People at increased risk of getting measles are those who are not fully vaccinated with two doses of MMR vaccine or have not had measles in the past. The risk of measles remains for up to 21 days after contact with a case of measles.
The HSE has warned that people who are sick should not attend any congregated settings such as crèche, school, work or religious gatherings until they have recovered from illness.
If you think you may have measles, stay at home and phone your GP for advice.
“Measles can be a serious illness and is highly infectious. The best protection is to be fully vaccinated with two doses of MMR (Measles, Mumps, and Rubella) vaccine," said Dr Ruth McDermott, Public Health Doctor.
