The HSE is warning football fans intending to travel to Euro 2012 fixtures of a measles outbreak in Ukraine.
At least 5,000 cases have been reported in Ukraine, which is co-hosting the tournament.
There are also high measles rates in other countries playing in the tournament, including France, Germany and Italy.
The European Centre for Disease Prevention and Control said that it expects the epidemic to accelerate between now and June.
Measles is one of the most infectious diseases known to man. Fans who have not received the MMR vaccine are at risk of getting measles, which can lead to serious health complications.