The travel warning published this week in a respected medical journal shouldn’t have been necessary.

A safe and effective measles vaccine is widely available throughout the developed world. It was less than 20 years ago when this highly contagious disease was declared eliminated in the United States, thanks to widespread immunization.

But now, with measles cases topping 41,000 in Europe since January of 2018, health officials are warning U.S. travelers heading there to take precautions. Namely, ensuring you have all recommended vaccinations or boosters before departure to protect yourself and your family.

Those who aren’t taking a European vacation this summer could also be at risk. Recent travelers who are unvaccinated or inadequately vaccinated could potentially spread measles to those back home.

The travel warning appeared as a special report in this month’s issue of “Pediatrics.” Its authors are respected researchers at the U.S. Centers for Disease and Prevention (CDC). They’re right to sound the alarm. Europe is a popular destination but many travelers don’t take the same medical precautions those journeying to more exotic locales do.

But the risk of infection is real, especially with European case numbers continuing to climb. Eight countries have ongoing outbreaks — among them, England, France, Greece and Italy. The number of cases is the highest reported since the early 1990s. Sadly, there have been 37 deaths.

Low vaccination coverage is the “biggest contributing factor to the increase” in cases, the CDC experts write. Their warning ought to be heeded in the U.S. as well. Since the beginning of the year, 1,044 cases have been reported in 28 states. Thankfully, Minnesota isn’t among them — yet.

Minnesota did have a serious measles outbreak in 2017. Yet the state’s vaccine laws are regrettably lax. It is among the 15 states that allow parents to cite “personal beliefs” for opting children out of school-aged immunizations. Lawmakers in Maine and Washington ended this exemption this year. New York took even stronger action, ending opt-outs for religious reasons, something that most states, including Minnesota, continue to allow.

Lawmakers here had little appetite for tightening vaccine exemption laws this year. That needs to change in 2020.