As the number of people sick with measles keeps rising almost daily in the U.S. state of Washington and neighboring Oregon, health officials warn that complacent parents are putting their children at risk of contracting a virus that can potentially be lethal. Over 50 cases have been reported in the two states alone since the beginning of the year.

But the United States is far from being the only country that has recently observed a surge in measles cases, the World Health Organization warned in a report released Thursday. Worldwide, researchers estimate that there were 6.7 million cases in 2017, with the vast majority occurring in poorer countries. Between 2016 and 2017, reported cases surged by 30 percent — including in some unexpected parts of the world.

There were 15 times more measles cases in Europe last year than in 2016, and new outbreaks were also recorded in South America and parts of Asia. Authorities in the Philippines said this week that a recent outbreak of the virus — with more than 1,800 cases so far — could put millions of children at risk. Measles immunization rates in the East Asian country have fallen to 60 percent, down 15 percent from the previous year, in part because of fearmongering over vaccines in a country that already struggles to inoculate its poorest.

In Washington, the immunization rate is still at 90 percent, but researchers say that a rate of at least 95 percent is needed to prevent an outbreak.

“The picture for 2018 makes it clear that the current pace of progress in raising immunization rates will be insufficient to stop measles circulation,” Zsuzsanna Jakab, a Europe-focused senior official with the World Health Organization, was quoted as saying.

The Western Pacific region, which includes China, Australia, Pacific islands and large parts of Southeast Asia, is the only part of the world where vaccination rates against measles are on the rise (the Philippines being the exception), bucking the global trend. In many of those places, previous measles outbreaks have sharpened parents’ minds to the risks of the virus, and have limited resistance against vaccinations.

But in the wealthier countries where warnings of the virus are more likely to trigger a shrug of parents’ shoulders than real concern, the virus is returning or becoming more common once again.

World Health Organization official Martin Friede warned last November that “we are seeing sustained measles transmission in countries that had not previously seen measles transmission for many years.”

One reason for the global resurgence of measles could be complacency on the part of parents who consider measles to be among the least likely possible illnesses to affect their kids. New Zealand, for instance, celebrated the official elimination of measles in the country about two years ago. But international air travel can carry viruses from one country to another within hours, and the country is now also fighting a renewed outbreak of the virus.

In some places, complacency over vaccinations has been accompanied by outright rejection of the scientific evidence on measles vaccines that has saved over 21 million lives since 2000, according to the WHO. Unsubstantiated conspiracy theories on supposedly negative side effects of vaccinations, either against measles or in a broader context, have gained momentum in some communities, in the United States and other countries.

Deliberately spreading misinformation on vaccines to suggest that citizens are being lied to by their leaders has become a go-to recipe of some populist politicians, too. After years of railing against vaccines and even proposing a law against them in 2015, Italy’s Five Star Movement is now part of the country’s government and has softened its stance. But during its campaign against vaccines, coverage fell far below targets. The misinformation campaign may have cost lives: Last November, Italy had to declare a measles emergency after four people died and more than 4,000 fell ill.

In other countries, politicians would be glad to be able to provide vaccines. As Ukraine’s confrontation with Russia escalated in 2014, access to health care deteriorated and immunization rates immediately plummeted. Vaccines became hard to come by and the conflict disrupted vaccination routines, especially in the country’s east. Almost half a decade on, vaccination rates are increasing again — but over 50,000 cases last year show that it takes only a temporary drop in vaccination coverage for the disease to spread again years later.

That’s bad news for parents in Washington and around the world.

More on WorldViews: