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Not Sure If You Got the Measles Vaccine? Here's What to Do

Forty-three percent of the California residents currently fending off the disease didn’t know if they had the MMR shot or not.
February 20, 2015, 4:25pm

One of the scarier realities of the measles o​utbreak spreading in California at the moment is the fact that most of the people infected aren't anti-vaxxers or their children. According to the Center for Diseas​e Control, there have been 125 confirmed cases of measles as of February 11, with 110 cases from California. Of those 110, only 28 were "intentionally unvaccinated because of personal beliefs," the CDC reports.

Meanwhile, 47 of the infected patients didn't know if they had been vaccinated with the measles, mumps and rubella vaccine or not. So 43 percent of the California residents currently infected with measles had no idea whether or not they were immunized.

"This is a big problem because most of us don't remember or know which vaccines we have received and most of us don't retain our immunization records as adults," said Dr. Neal Halsey, the director of the Institute for Vaccine Safety at Johns Hopkins.

"I suspect that some of those people assumed, because they're an adult, that they weren't susceptible to measles because everybody thinks of it as a childhood disease," he said.

It seems like you're getting needles every other day as a kid, so many of us just assume we're immune to most vaccine-preventable diseases. But without proper records or parents with a good memory, it might be hard to tell. In the shadow of the current outbreak, that's got a few people wondering: what if I wasn't vaccinated?

You can make an educated guess based on a few things. The CDC's guid​elines say if you were born before 1957, you most likely had measles as a kid and are now immune. If you were vaccinated before 1968, you most likely ​got a killed virus vaccination, which is not effective. If you went to public school, and your parents didn't object to the MMR vaccine, you likely got vaccinated. But there's also a chance you only got one injection, instead of the recommended two.

But these are just guesses. If you're still unsure, what can you do?

"For people who don't know their status and are in an outbreak situation, or just want to make sure they're protected, the simplest thing to do is just to get another dose of vaccine," Halsey told me.

And if you're worried about something weird happening if you get a dose of the vaccine and you are already immune, Halsey said not to worry.

"If you're immune from having had the vaccine or having had the disease, then your immunity stops any of those viruses from multiplying and you don't have increased risk of fever or other things," Halsey said. He noted that there is always a very small risk associated with vaccines if you happen to be allergic, so make sure to talk to your doctor about it.

There is a blood test doctors can do to determine if you have immunity or not, but for MMR you'd need three separate tests, which would be expensive and time consuming. If you were found to not be immune to any one of the diseases, you'd need to go back into your doctor for the vaccine anyway, so Halsey said it's more prudent to just go ahead with the shot if you're really unsure.

And even if you don't live near the outbreak, you don't really want to roll the dice on this one. Measles gets increasingly more severe as you age, Halsey said. Adults who catch it are at a 25 percent risk of hospitalization and about one in every 1,000 measles patients will suffer encephalitis—that's inflammation of the brain—which Halsey said can lead to "devastating complications."

Besides, even if you think you can handle a bout of measles, it's essential to have a critical mass of people immunized if we want to achieve herd​ immunity. This protects those who can't be vaccinated, like the twelve ba​bies who currently have measles in California because they were too young to be vaccinated. And there is a whole list of other vacci​nes the CDC recommends. If you don't know and you don't have your childhood records or parents who can help you confirm, now would be a great time to make an appointment with your doctor.