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Measles has surged in some parts of the US. Some people might need a booster.

The disease is spreading mostly among unvaccinated children, though adults may also be at risk.

Measles Makes Comeback, As Outbreak Happens In 22 States
So what’s driving the uptick in measles cases? Most (some 70 percent) are happening in unvaccinated people.
George Frey/Getty Images

Measles cases in the US have surged to a 25-year high — and the vast majority involve children who weren’t fully immunized.

As of April 26, at least 704 people have been sickened by the virus this year, the highest number since 1994, according to the Centers for Disease Control and Prevention. Twenty-two states have reported cases, and more than a third involve kids under the age of 5. Nearly 70 children have already been hospitalized because of complications related to the virus.

For decades, public health experts have been asking people to vaccinate their kids against measles, a highly contagious childhood illness that can, in rare cases, cause brain swelling, hearing loss, and even death.

For one thing, the vaccine is highly effective, so getting immunized is a really good way to prevent infections.

Even more importantly, the more people who get vaccinated, the more we increase “herd immunity,” or the chances of protecting even those in a community who can’t or shouldn’t be vaccinated (like newborn babies or people with allergies to vaccine ingredients).

But despite that, the number of unvaccinated people in certain pockets of the country has been creeping up, threatening herd immunity. And now measles is suddenly a significant public health problem again.

“Vaccine-preventable diseases belong in the history books, not in our emergency rooms,” said Health and Human Services Secretary Alex Azar in a press briefing Monday. “We are reminding all Americans to talk to their doctors and ensure they are up to date with CDC’s recommended vaccination schedule.” Here’s why — and what people can do to prevent the virus from spreading even further.

Measles was eliminated in the US but unvaccinated travelers have brought it back to places where it has spread

Before a vaccine was introduced in the US in 1963, there were 4 million measles cases with 48,000 hospitalizations and 500 deaths in the US every year. That means for anyone born before 1960, there’s a good chance they suffered through a measles infection (and developed immunity to the virus as a result).

The beauty of the vaccine is that most people who get the recommended two doses will never get sick with measles, even if they’re exposed. And by 2000, because of widespread vaccination, the virus was declared eliminated in the US: Enough people were immunized that the virus no longer circulated here, outbreaks were uncommon, and deaths from measles were scarce.

But that’s now changing. Globally there’s been a 300 percent rise in measles cases this year compared to the same period in 2018, according to the World Health Organization. Ukraine, Madagascar, India, Pakistan, Philippines, Yemen, and Brazil are among the countries most affected, according to WHO.

The US is also seeing a record number of measles cases: more than 700 as of Friday — which is the highest number since 1994, years before the disease was officially eliminated.

So what’s driving the uptick? The vast majority of cases (474) have occurred in Orthodox Jewish communities in New York City and the New York suburb of Rockland. An outbreak at two Los Angeles universities is also now rapidly spreading. So most of the new cases are concentrated in New York and California. (The CDC’s website has a detailed overview of US cases and outbreaks.)

Eight-eight percent of all cases have involved outbreaks in what CDC calls “close-knit communities,” or people of a similar background who share values and beliefs and interact often.

To date, all outbreaks have been linked back to international travel: Americans or travelers who picked up the virus in a country where measles is spreading more broadly and then brought it back to the US. (The top three countries where measles cases in the US originated were Ukraine, Israel, and the Philippines.) But, again, most of these cases — more than 500 — are happening in unimmunized people. Had these travelers gotten their vaccines, we wouldn’t be seeing a record number of cases right now.

Get your vaccines — even if you think you’ve been vaccinated

The CDC is now recommending that everyone — children and adults — makes sure they’re up to date with their vaccines. The top priority, though, is people who are at higher risk of the disease: those who are traveling internationally, live in communities (particularly close-knit ones) with ongoing or recent outbreaks, or work in health care settings.

Measles is prevented through the combination MMR (measles, mumps, and rubella) shot. The CDC normally recommends that children get two doses: the first dose at 12 through 15 months of age, and the second at 4 through 6 years of age.

But because of the recent outbreaks here, and the surge in cases globally, health officials are suggesting babies as young as 6 months get a first dose before they travel. For children 12 months or older, CDC recommends 2 doses separated by 28 days.

Adults who have not had measles or who never got their shots should also ask their doctor about getting two doses separated by 28 days.

If you aren’t sure of your vaccine status, you can also ask your doctor about a booster or request a blood test to check on your immunity. People born before 1957, when measles was widespread, are assumed to be immune since they probably suffered through an infection. Those born in the years 1957 to 1989 may not be fully immunized, since they likely got an older and weaker version of the vaccine, and it was common then to give kids only one shot.

“We have come a long way in fighting infectious diseases in America,” Azar said, “but we risk backsliding and seeing our families, neighbors, and communities needlessly suffer from preventable diseases.”

President Trump, who has previously spoken out against vaccines, came to their defense last week. “They have to get the shots. The vaccinations are so important,” Trump told reporters. “This is really going around now.”

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