Measles, once eliminated in the Americas, has come roaring back.
From 2016 to 2017, the number of reported cases in the region jumped 6,358 percent, to 775, largely fueled by an ongoing outbreak in Venezuela that has since infected thousands more. Along with a spike in measles in Europe, the Venezuela outbreak contributed to a 31 percent worldwide increase in reports of the highly contagious disease in 2017, according to researchers from the World Health Organization and the U.S. Centers for Disease Control and Prevention.
“Both the Americas and the European regions have the resources to stop measles, and it’s not happening,” says William Moss, an infectious disease epidemiologist at the Johns Hopkins Bloomberg School of Public Health who was not involved with the report.
The apparent jump comes after years of steady progress toward reducing the spread of the disease. Even taking the recent rise into account, reported measles cases from 2000 to 2017 have dropped 80 percent worldwide — from 853,479 to 173,330 — as have estimated deaths from the disease, researchers say in the Nov. 30 Morbidity and Mortality Weekly Report. Measles vaccination prevented an estimated 21.1 million deaths over that time, the report says, though it continues to be a leading cause of vaccine-preventable infant deaths globally.
“Global efforts to eliminate measles continue to make progress,” says Rebecca Martin, director of CDC’s Center for Global Health in Atlanta. “Despite these gains, multiple regions have experienced large measles outbreaks in 2017, primarily due to low vaccination coverage nationally or in geographic pockets, illustrating how fragile gains in disease elimination can be.”
Coughing and sneezing easily spreads measles, and the virus can survive for up to two hours in the air. Symptoms start with fever and cough, followed by a red-spot rash several days later. An infection can lead to pneumonia or swelling in the brain and can be fatal. Before the vaccine was introduced, measles caused an estimated 400 to 500 deaths in the United States annually.
Overall, researchers found that reported cases of measles increased in five out of six regions from 2016 to 2017, including in Africa and the eastern Mediterranean, where — with 72,603 and 36,427 cases respectively — the disease is most common. In Africa, poor health infrastructure is a contributing factor, while conflict and refugees make measles control challenging in the eastern Mediterranean region, Moss says.
The striking jump in cases in the Americas was driven by a big outbreak that began in Venezuela in 2017 and spread to neighboring countries, including Brazil. Just two years ago, WHO declared that measles was no longer circulating in the Americas, and therefore had been eliminated from the region (SN Online: 9/27/16). With elimination, there can still be small outbreaks, but they are due to travelers bringing the virus home.
But as of July 2018, endemic measles has been reestablished in Venezuela, the report says, which means that the virus has been circulating there for more than 12 months. There were 3,545 confirmed cases of measles in the country as of August 20, with 62 deaths, according to the Pan American Health Organization. Venezuela’s recent political upheaval, which spurred a collapse of the public health infrastructure, has fueled the outbreak there. An exodus of Venezuelan citizens has spread the virus to other countries.
“Measles elimination is a fragile state,” says Moss. “If we turn away from measles control and elimination, it’s going to come back.”
In Europe, where from 2016 to 2017 reported cases rose 458 percent, to 24,356, the underlying problem is the refusal of parents to vaccinate their children, Moss says. Vaccine hesitancy is the reason for outbreaks in the United States as well, with decades-long success at preventing measles undermining efforts to further control the disease. “People don’t see it as an important problem, and that’s when you may be more likely to see vaccine hesitancy,” Moss says.
Worldwide, there were about 41,000 more cases of measles reported in 2017 compared with 2016, with the totals rising from 132,328 to 173,330. That’s a hike from 19 cases per million people to 25 per million — and far short of WHO’s goal of reducing the global incidence of measles to less than five cases per million annually. Some of the rise in cases also was due to an increase in the number of countries reporting data, according to the authors.
It’s difficult to get a true measure of measles’ global impact. Cases worldwide are “grossly underreported,” Moss says. But there’s no question that there have been worrying outbreaks. “This is still a problem,” Moss says. “And it’s a global problem.”