A Measly Epidemic

Thanks in part to anti-vaxxer hysteria – now getting a boost from Christie – the measles are making a comeback:

Between Jan. 1 to 30, 102 cases of the measles were reported to the CDC from 14 different states. The majority of the cases are from an ongoing outbreak linked to Disney California Adventure Park in Anaheim, Calif. The CDC says the majority of people who got measles were unvaccinated. … The people infected in the current outbreak have exposed others at the amusement park as well as schools, daycares, emergency departments, airplanes and outpatient clinics the CDC says. In 2014, the Unites States had the highest number of measles cases reported in over 20 years, at over 600 cases.

In response to the outbreak, the White House is urging “vaccine-hesitant” parents to make the right choice and get their kids their shots. Steven Salzberg lays the blame for the outbreak squarely at the feet of the Jenny McCarthyites:

The problem arises from California’s vaccine exemption policy: although public schools require kids to be vaccinated, parents can exempt their kids simply by saying they have a personal objection to vaccination. It’s not just California: only two states, Mississippi and West Virginia, don’t allow parents to claim a philosophical or religious exemption to vaccines  And Colorado has the worst rate of vaccination, at just 82%, primarily due to parents claiming a “philosophical” exemption.

These parents are the anti-vaxxers.

Thanks to them, we now have large pockets of unvaccinated children through whom epidemics can spread further an faster than we’ve seen in decades. The CDC reports that in 2014, 79% of measles cases in the U.S. involving unvaccinated people were the result of personal belief exemptions.

But as Julia Belluz voxplains, outbreaks like these aren’t simply the fault of such parents individually; the disease spreads in communities where vaccination rates are especially low:

It’s not actually a rising anti-vaxx tide or naturopathic, private school mothers driving a return of vaccine-preventable disease here. It’s not even low-income folks who wind up getting sick, and it’s especially not undocumented migrants bringing in viruses, the CDC’s [Jane] Seward says: “The people getting measles are those that travel abroad, come back, and live in a community among people who weren’t vaccinated.” Some years, we get 40 “importations.” Last year, there were about 65. “This is more than normal,” she added, “and it reflects travel patterns and where measles is active globally.”

The travelers spark outbreaks when they hit geographic clusters of unvaccinated people, like the one in Ohio [among the Amish community, where last year’s measles outbreak was centered]. These infectious disease powder kegs exist all across the US, waiting to be sparked.

Marcel Salathé considers what these anti-vaxxer pockets mean for our society’s herd immunity as a whole:

When we analyzed data from Twitter about sentiments on the influenza H1N1 vaccine during the swine flu pandemic in 2009, we found that negative sentiments were more contagious than positive sentiments, and that positive messages may even have back-fired, triggering more negative responses. And in measles outbreak after measles outbreak, we find that the vast majority of cases occurred in communities that had vaccination coverages that were way below average.

The sad truth is this: as long as there are communities that harbor strong negative views about vaccination, there will be outbreaks of vaccine-preventable diseases in those communities. These outbreaks will happen even if the population as a whole has achieved the vaccination coverage considered sufficient for herd immunity.

An exasperated Aaron Carroll outlines why failing to vaccinate against measles – which, as Michael Byrne reminds us, is a very nasty disease – is so dangerous:

The system breaks down, and outbreaks occur, when more people are susceptible. Everyone, for instance, is susceptible to Ebola at a certain point in the illness. So we have to be careful to quarantine people who are infected when they are sick. But Ebola is relatively hard to catch. It has an R nought of 2, meaning that an infected individual might infect, on average, 2 others. But measles has an R nought of 18. It’s one of the most infectious pathogens around.

Quarantining is difficult, if not impossible. The virus is unbelievable hardy and easy to catch. So the absolutely, positively best thing you can do it to be vaccinated. Period. I should point out that it also doesn’t matter to the outbreak why people remain unvaccinated and susceptible. It can be because of religious reasons. It can be because of irrational fear. It can be because they’re “hippies”. I don’t care – the outbreak is the same.

Sarah Kliff revisits the anti-vaxxers’ spurious objections to inoculation and why they’re wrong:

Objections to vaccination among those healthy enough to get immunized (those of us over the age of one, essentially) typically just aren’t good enough to justify the risk. Much of it revolves around the safety of the vaccine. Even in the Amish community in Ohio, it wasn’t a religious belief that caused low vaccination rates — and laid the groundwork for a huge outbreak. Instead, it was news of two nearby children suffering complications from the shots that turned the community against vaccination.

So let’s clear that fact up here right now: the measles vaccine is, without a doubt, safe. Study after study after study confirms this. The study that suggested the measles vaccine was not safe — and had possible links to autism — was retracted by the academic journal Lancet in 2010. The researcher who published the study, Andrew Wakefield, was stripped of his medical license in Britain. Not only is the measles vaccine safe, it’s also incredibly effective.

And Elizabeth Stoker Bruenig mulls over why the anti-vaxx movement has gained ground in recent years, and why that’s cause for concern:

For Americans, the reality is that parents who refuse to vaccinate their children make their choice in relative comfort. Parents with toddlers today do not remember the scourges of prior centuries: the bubbling blisters of smallpox, the iron lungs of polio, the florid rash of measles that has, since 2010, taken the lives of over 4,500 people in the Democratic Republic of Congo, most of them children under five. All of those things, thanks to time or distance, go out of thought and out of mind. Moreover, since most American children—thanks to the good sense of most American parents—are still vaccinated, the likelihood that these plagues will come roaring back has always seemed distant. Now, perhaps not so much.

Lastly, Chris Ingraham breaks down vaccination rates by state and looks for patterns, though they’re actually hard to find:

Alabama usually accompanies Mississippi at the bottom of health rankings, but it does even better when it comes to vaccines — 77 percent of toddlers there are completely covered. Overall, state-level vaccine rates buck the familiar trend of “south= bad, northeast and west = good” that we see on countless other health measures. New Hampshire kids are well-vaccinated, but Vermont and Maine kids less so. Mississippi comes in at #12 in the rankings, while just across the river Arkansas is dead-last. California, currently in the news for a large measles outbreak at Disneyland, is squarely middle-of-the-pack at number 30.

It’s tough to tease out demographic patterns behind vaccination rates. In California, some affluent areas have lower vaccination rates than the average. But looking at all 50 states, there’s a small correlation between increased income and increased vaccination. Some people maintain that vaccine skepticism is strongest on the left, but the data don’t support that notion.