THE number of measles cases in Europe has hit a record high of more than 41,000, the World Health Organization said Tuesday.

That means that, little more than halfway through the year, 2018 is already the worst year on record for measles in Europe in a decade, WHO said. So far, at least 37 people have died of the highly contagious virus.

A lack of vaccines is partly to blame in some affected countries, but in others, it’s the refusal to get kids vaccinated on time that is driving epidemics, WHO said.

“Following the decade’s lowest number of cases in 2016, we are seeing a dramatic increase in infections and extended outbreaks,” Dr. Zsuzsanna Jakab, WHO Regional Director for Europe, said in a statement.

More cases in any country means more cases can be spread by travelers, including to the U.S. Measles has been eliminated in the U.S., but every year, the virus is imported by travelers and can spread quickly in areas where people are not properly vaccinated.

Most of the cases in Europe are in Ukraine, which has had 23,000 cases, WHO said.

The number of measles cases varies greatly from year to year. “So far, the highest annual total for measles cases between 2010 and 2017 was 23,927 in 2017, and the lowest was 5,273 in 2016,” WHO said.

In the U.S., the Centers for Disease Control and Prevention (CDC) has reported 107 measles cases as of the middle of July this year. Case counts also vary widely in the U.S. from year to year and range from 55 cases in 2012 to 667 in 2017. Last year, 118 cases were reported by the CDC. (SD-Agencies)