Don’t Be Surprised by Arizona’s Measles Outbreak: Its Vaccination Rates Stink

Arizona is home to the largest measles outbreak in the US so far this year. It originated at the Eloy Detention Center, an immigration detention centre about a two-hour drive from the Mexican border where migrants are held while awaiting trial or deportation. Twenty-two cases of measles have been reported there over the last few months, including one that required a four-day hospital stay. (No one has died so far.)

While some Republican pundits will most likely point the finger at the immigrant detainees—a tactic they've relied on during past outbreaks—health experts say that in reality, it was unvaccinated workers and Arizona's already dismally-low vaccination rates that allowed this outbreak to spread.

Arizona is a state where immunization rates sag, compared to the rest of the US. Last year, Arizona had the lowest vaccination rates in the country for measles, mumps, and rubella: Only 84 percent of children between 19 and 35 months were up to date on the shot in that state, compared to 91.5 percent in the US overall.

This is partly due to lax exemption requirements. To send an unvaccinated child to public school in Arizona, parents only need to sign a form saying they understand the decision they've made, if they've opted to forego a vaccine.

This leads to anti-vaxxers skipping their kids' shots, but also to plenty of "convenience exemptions," according to Thomas Schryer, the director of public health for Pinal County, where the current outbreak is taking place.

"These are folks that go to register their kids for kindergarten and they haven't gotten around to getting their kid vaccinated, so they sign off on the form, then don't follow up," Schryer told me. "It's easy to opt out. Frankly, it's too easy."

The immigration detention center, where the first measles case emerged in May, is home to about 1,250 migrants from around the world awaiting trial or deportation, many of whom come from developing countries where access to healthcare is limited. Naturally, this means the immunization level among detainees can be spotty.

Schryer said in all likelihood the first case came from one of the detainees who was already infected upon arrival—measles has an incubation period of up to 21 days, and there had been no other cases in the community this year. But the outbreak never would have spread beyond a handful of people if the employees at the center been fully vaccinated, Schryer told me.

"Had the staff been vaccinated and had herd immunity, then there wouldn't have been any of these staff cases," Schryer said. "It would have burned out pretty quick."

Instead, while detainees were all vaccinated within days of the first case, getting the workers vaccinated has been a grind. The majority of workers are from either US Immigration and Customs Enforcement, or from the private prison company Corrections Corporation of America, which owns the facility. CCA was quick to get its workers up to date on shots—employees had to either get immunized, prove immunity, or start wearing a surgical mask at work, a spokesperson told me. But ICE has been dragging its feet, according to Schryer.

ICE did not immediately respond to a request for comment, but a spokesperson told the told the LA Times that the agency had "instituted several measures to prevent the disease from spreading further, including providing immunizations, referring staffers to nearby clinics, handing out fliers and pamphlets on the dangers of measles and providing masks and gloves."

So while people like Donald Trump love to blame immigration for outbreaks like this, the real problem lies with lax vaccine exemption laws and low immunization rates. In a facility like Eloy, where a vulnerable population is kept in close quarters and disease can spread quickly, the need to establish herd immunity becomes even more imperative.

Had workers been more widely immunized beforehand, this outbreak could have been quelled much sooner, potentially putting far fewer people at risk.