Measles is on the rise again, all around the globe.
Though the number of people affected in the U.S. is still relatively low compared with the countries hardest hit, there are a record number of U.S. measles cases — more than 700, so far, in 2019, according to the CDC — the highest since the disease was eliminated in the U.S. back in 2000.
Measles has been documented in more than a third of states, with large outbreaks in New York and Washington.
And although the majority of people getting the illness now were never vaccinated, the expanding outbreaks have raised new questions about whether some older adults — including many of those born before the mid-1960s — should be revaccinated, along with some younger people uncertain of their immunization status.
According to the Centers for Disease Control and Prevention, people who were vaccinated prior to 1968 with an early version of the vaccine, which was made from an inactivated (killed) virus, "should be revaccinated" with at least one dose of live attenuated measles vaccine.
Today's recommended vaccine is known as MMR and protects against measles, mumps and rubella.
"This recommendation is intended to protect those who may have received killed measles vaccine, which was available in 1963-1967 and was not effective," according to this Q & A on measles from the CDC.
Since few people born in the 1960s are likely to have their vaccination records handy, many may be uncertain as to whether they got the ineffective vaccine or were later vaccinated with the newer version. In addition, women of any age who are considering pregnancy should make sure their MMR vaccinations are up to date, according to the CDC.
If you're uncertain of your immunization status, it's safe, with a few exceptions, to go ahead and get an MMR shot now to minimize your chances of getting measles. And that's the point: As an adult, you're likelier to develop complications from the illness, which can include pneumonia and brain swelling, health officials say.
"There's no downside to getting a dose of measles vaccine," says William Schaffner, a professor at Vanderbilt University and an infectious disease and vaccine expert. "If you're [already] protected, it won't help much, but it won't harm you. And if you happen to be susceptible, it will give you over 90 percent protection."
This advice also applies to people born between 1957 and the early 1960s who may not have been vaccinated against measles at all.
Schaffner says it's not a blanket recommendation — do check with your doctor. But it's reasonable to consider getting the MMR shot, especially if you live in a community where there's an outbreak of measles or if you're traveling out of the country to places where there are outbreaks currently — including Israel, Brazil, Japan, the Philippines and some countries in Europe and Africa.
"If you were born between 1957 and 1963 and you are unsure of your measles immunization status, and you are so inclined, sure! Go ahead and get a dose of MMR," Schaffner says.
Another option if you're unsure of your vaccination status is to get a blood test to determine whether you are immune. But the CDC says this is likely to take two doctor's visits and cost more than a vaccination. So it may be easier to just get the shot.
"There is no harm in getting another dose of MMR vaccine if you may already be immune to measles," states this CDC measles summary.
Meanwhile, most of the eldest Americans — those born before 1957 — are considered to be protected against measles and don't need a booster, because the virus was so widespread in their youth that nearly everyone was exposed.
The CDC does have some exceptions to that rule: Some health care workers born before 1957 (who have a higher chance, amid the current outbreaks, of coming into contact with people who have measles) should consider getting the MMR vaccine.
Still wondering which advice best fits you? Check with your doctor.
So far, even the hundreds of measles cases reported in the U.S. this year pale in comparison with the 1950s, when millions of people each year got measles. The CDC says the longer the current outbreaks continue, the greater the risk the disease will regain its foothold in the United States.
RACHEL MARTIN, HOST:
If you got your measles vaccine as a kid, do you need to be revaccinated as an adult? It's an important question that's coming up as health officials now scramble to contain the measles outbreaks across the country. Here's NPR's Allison Aubrey.
ALLISON AUBREY, BYLINE: The measles vaccine is incredibly safe and effective, but it wasn't always that way. Many people born in the 1960s who received an early version got a vaccine made from an inactivated virus. And Vanderbilt University's William Schaffner says this didn't work so well.
WILLIAM SCHAFFNER: It turned out to be a very weak and sometimes even harmful vaccine.
AUBREY: This vaccine was given between 1963 and 1967. And for people who got it, the CDC recommends that you talk to your doctor about getting revaccinated with the current, live measles, mumps and rubella vaccine known as the MMR. The CDC says even if you're not sure whether you have protection against measles or got the ineffective vaccine back in the '60s, you can opt to get a dose of the MMR vaccine. William Schaffner says there's no downside to getting revaccinated.
SCHAFFNER: Even if you're protected, it won't help much, but it won't harm you. And if you happen to be susceptible, it will give you over 90% protection.
AUBREY: And this advice also applies to people born between 1957 and the early 1960s, who may not have been vaccinated at all as children. Schaffner says, it's not a blanket recommendation, but it may be a good idea for people who live in communities where cases of measles have been reported or for those traveling to other countries that have measles, including countries in Europe.
SCHAFFNER: Brazil, Israel, Japan, the Philippines - if you're traveling to any of those places and you're at all uncertain about your measles protection, get vaccinated because if you get measles as an adult, you're much more likely to get the complications.
AUBREY: And this includes pneumonia as well as encephalitis, or brain swelling. Now, people born before 1957 are considered to be protected against measles. That's because the virus was so widespread nearly everyone was exposed.
So far this year, measles has been documented in more than a third of states in the U.S. Most of the illnesses occur in children. It can start with a runny nose, a cough. And when it gets worse...
SCHAFFNER: You feel miserable. You have aches and pains. You have high fever.
AUBREY: The hundreds of measles cases reported in the U.S. this year pales in comparison to the 1950s. Before there was a vaccine, the CDC says 3 to 4 million people each year got measles. Schaffner says we don't want to turn back the clock. That's why it's so important for parents to vaccinate their children, which the CDC says is the most effective way to prevent the disease.
Allison Aubrey, NPR News. Transcript provided by NPR, Copyright NPR.