Yahoo Lifestyle Why one MMR dose isn’t enough: a pediatrician clears up measles vaccine myths
“93% protected? Not exactly.” That’s the message Dr. Krupa Playforth, a board-certified pediatrician known as The Pediatrician Mom, wants parents to understand about the MMR (measles, mumps, rubella) vaccine. In a recent Instagram video, the social media famous doctor runs down a common misconception floating around the internet.
Related: Measles outbreak: What parents need to know to keep their kids safe
“Articles online keep saying if your child has had the first MMR dose, they’re 93% protected against measles, and that’s not technically true,” Playforth explains. “What most people understand when they read something like that is, ‘Okay, if my child has had one dose of MMR, they have partial immune protection against measles, even if it’s not complete.’ But what we actually mean is 93% of kids mount an immune response to the first MMR. 7% don’t.”
And that 7%? Still completely vulnerable. That’s where the second dose comes in.
Why two doses matter
The MMR vaccine isn’t a one-and-done situation. Dr. Playforth emphasizes that “the reason we give a second dose is to give that 7% a chance to mount an immune response.” After the full two-dose series, 97% of kids have protection against measles—a massive improvement. And the remaining 3%? “For the remaining 3% and for those who can’t get MMR, we actually rely on herd immunity,” she adds.
Why this matters right now
Measles cases are making a comeback in the U.S., with outbreaks in multiple states. Measles is one of the most contagious viruses out there—90% of unvaccinated people exposed to it will get infected. The good news? The vaccine is incredibly effective when both doses are given on schedule.
If you’re traveling, listen up
Planning a trip? Measles is still widespread in many countries. Dr. Playforth urges parents to check their child’s vaccination status before traveling: “If your child is over the age of one, ideally you want to set it up so that they’ve had two doses of the MMR vaccine, so that they fall within that 97%.”
What parents need to know about measles and the MMR vaccine:
One dose isn’t enough—make sure your child gets both doses for full protection.
Measles spreads like wildfire—one infected person can spread it to 9 out of 10 unvaccinated people.
Symptoms start slow but escalate fast—it begins with fever, cough, and runny nose before leading to a full-body rash.
Complications can be severe—measles can cause pneumonia, brain swelling, and even death, especially in young children.
Check vaccines before travel—outbreaks are happening globally, and exposure risk is higher when traveling.
For more information on measles and the MMR vaccine, visit the American Academy of Pediatrics (AAP) or the Centers for Disease Control and Prevention (CDC).
Related: Measles outbreaks have been reported in multiple states, AAP says
Source:
After the full two-dose, 97% of kids have protection. Science Direct. 2023. “Two-dose measles vaccine effectiveness remains high over time.”
90% of unvaccinated people exposed to it will get infected. Center for Disease Control and Prevention. 2024. “Measles in the United States — March 2024.”
One infected person can spread it to 9 out of 10 unvaccinated people. Epidemic Control Toolkit. 2023. “Which interventions are most effective for prevention and control?”
Symptoms start slow but escalate fast. Center for Disease Control and Prevention. 2024. “Measles Symptoms and Complications.”
Complications can be severe. American Academy of Pediatrics. 2019. “Measles associated with numerous complications, death.”
Check vaccines before travel. Center for Disease Control and Prevention. 2024. “Protect yourself against measles.”
Related: Measles outbreaks have been reported in multiple states, AAP says
