2014 was an alarming year for measles cases. There were, according to the CDC, 23 outbreaks and 644 cases. And already, the first month of 2015 has been marked by a measles outbreak at the Disneyland in California. The California Department of Public Health has confirmed 59 cases so far.
Some media outlets have been quick to "blame the unvaccinated" for the California outbreak, because most of those cases were in people unvaccinated against the disease. There's more than one reason a person might not have a measles vaccine: they might unintentionally have fallen behind the schedule of shots, simply been too young—or have refused the vaccine entirely.
But while doctors are using the publicity to push for the recommended vaccination schedule, it's not correct to simply blame the anti-vaccine movement for these outbreaks. Ohio’s 2014 outbreak, for instance, accounted for 382 of that year’s cases—and the virus that caused it was carried from the Philippines, which has been struggling with a massive outbreak of the disease since 2013, by an Amish missionary.
Julia Belluz for Vox explains that while this one traveler wasn’t responsible for all the 2014 cases, the missionary "turned an otherwise unremarkable year for this virus into one of the worst in recent history."
The Ohio Amish community the missionary returned to was full of unvaccinated people. Amish communities in general refrain from a host of modern inventions and conveniences. They go without cars, public utilities like electricity, telephones or computers. The exact rules can differ from community to community, but the purpose is to keep their culture strong and separate. In this Ohio community, however, vaccines weren’t avoided because of religious beliefs, but because two Ohio kids had allegedly gotten sick after their MMR shot in the 1990s. The community stopped vaccinating.
That make the virus spread quickly once the missionary returned home. Belluz writes that measles is incredibly contagious:
A person with measles can cough in a room, leave, and — if you were unvaccinated — hours later, you can catch the virus from the droplets in the air that they left behind. No other virus can do that. It also lives on surfaces for hours, finding new hosts in the unimmunized.
"Measles is very contagious, so once [the Ohio missionary] felt better, he went to church, and the church was in somebody's house," Fletcher says. "The majority of those first cases, we linked back to him. They had all attended church in that house."
The rural location and the lack of phones made it difficult to tell people who may have been exposed to stay in quarantine. But no one died, and only nine people were hospitalized by the time the outbreak was under control.
While the Ohio story doesn’t line up with the idea that "anti-vaxx" sentiment has brought measles back to the U.S., it does emphasize the importance of getting vaccinated. Only about 2 percent refuse vaccines, and that number hasn’t grown in the past decade. But that country-wide average obscures the fact that some communities can have a high proportion of unvaccinated people. Most cases are sparked by travelers who bring the virus back with them.
The message is simply more nuanced, points out Keith Kloor in a post at Discover’s Collide-a-Scape blog. "The low-vaccination enclaves are a public health problem," Yale researcher Dan Kahan told him. "But attributing them to general anxiety over vaccine risks in public is not useful — and in fact is itself dangerous."
The problem is that this one narrative obscures the more complicated truth—that there are many causes for under-vaccination. It’s not just that people refuse vaccines. Sometimes it's simply hesitation, absentmindedness or even lack of opportunity that prevents them from getting vaccinated. Addressing all the causes, Kloor points out, is the only way to properly combat these diseases.