The global health watchdog also said vaccine supplies and "underperforming disease surveillance systems" in several European countries have contributed significantly to the rash of recent measles cases.
World Health Organization reported that there were over 1,200 suspected cases in Ireland during 2017.
While Europe has seen a sudden increase in cases, there were 89,780 measles deaths globally in 2016, an annual rate that fell below 100,000 for the first time.
The spike comes following a record low of 5,723 cases in 2016. "Over 20 000 cases of measles, and 35 lives lost in 2017 alone, are a tragedy we simply can not accept", says Dr Zsuzsanna Jakab, WHO Regional Director for Europe.
Europe has been struggling to control measles for years.
That's what is happening in Europe, as well.
Actions to stop the current outbreaks and prevent new ones are taking place on various fronts. Measles is one of the most infectious viruses - it infects 90 percent of people who are exposed to it if they aren't immune, and it can hang in the air and infect people who enter a room as long as two hours after an infected person has left.
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The spokesperson said: "If people are unsure of their vaccination status they are advised to get an MMR vaccine, as even if they do have 2 doses of MMR a third dose is not harmful".
However, the figures for Ireland show a reverse trend - with more cases in 2016 than in 2017.
The countries with the biggest outbreaks were Romania and Italy, each of which saw more than 5,000 cases, and Ukraine, with more than 4,700 cases.
The WHO attributed the high number of reported cases in all three countries to the overall drop in immunisation coverage provided by Bucharest, Rome, and Kiev, especially to those from at-risk communities.
Despite the increases in Europe, WHO says vaccination against measles is a success story.