Measles in Disneyland is entirely preventable

NPR recently reported, “Measles makes an unwelcome visit to Disneyland.” Nine people who visited Disneyland theme parks in California over winter break had caught measles, almost all of them unvaccinated children. The next day, ABC reported that the number of cases has grown to 19. Of these, only two had been fully vaccinated. Some of the cases were too young to receive vaccines, others apparently chose not to get vaccinated. Since measles is one of the most contagious illnesses on earth — it can spread just through the air, with infectious particles floating around for hours after a victim has left the room — we can expect these cases to lead to dozens or hundreds more. A lot of these sick people were probably traveling on planes all over the country. Who knows how many people have now been exposed?

Measles is a serious illness. Prior to widespread vaccinations, 3-4 million people caught measles each year in the USA; of these, 400 to 500 died, 48,000 were hospitalized, and 4,000 developed encephalitis (brain swelling, which can lead to death or permanent disability.) We’ve kind of forgotten that because measles has become so rare. We do not want measles to come roaring back.

Measles vaccine itself is very, very effective.  98 percent of people who’ve gotten the two dose series remain completely immune for life. That’s incredibly effective, and just as effective as “natural immunity” from the disease, but without the misery and risk of the disease itself. But 98 percent effective means that 2 percent of vaccinated individuals are still susceptible. In a huge Disney theme park with thousands of people wandering around in mouse ears, even a highly vaccinated crowd is going to include some people who are not well protected. And they don’t know who they are.

Some people can’t be vaccinated at all. Babies less than one (who have a high risk of complications from measles) can’t receive the vaccine; nor can many people who have immune deficiencies.

The only way to protect susceptible individuals (those who can’t get the vaccine, or those in whom the vaccine didn’t work) is to avoid contact with measles. If measles is very rare, even unvaccinated people will probably be safe. But once measles isn’t rare, well, we’re asking for trouble.

We had measles beaten.  In the 2000s, it had been completely eliminated from transmission in the U.S., thanks to a very safe and effective vaccine. Then one nutjob created anti-vaccine hysteria with one fraudulent study. He made the damn thing up. And we’re paying the price.

We can beat this. Parents need to make sure they’re vaccinating their kids, on time and on schedule. They need to let their neighbors know it’s the right thing to do. Parents, who are genuinely afraid, need honest, reliable information about the great wealth of information we have, which overwhelmingly supports the safety and effectiveness of vaccines. People who are just loudmouths and liars, fanning fear for their own twisted reasons, should be shunned. It is time to end the fake “vaccine controversy” to protect the health of our children and our communities.


As of January 17, there are now 51 cases, including secondary cases who were not at Disneyland. People who caught measles at the theme park have now gone home and are spreading measles in other communities.

Roy Benaroch is a pediatrician who blogs at The Pediatric Insider. He is also the author of A Guide to Getting the Best Health Care for Your Child and the creator of The Great Courses’ Medical School for Everyone: Grand Rounds Cases.

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