MMR vaccine myths vs. facts: What parents should know
The MMR vaccine, also known as the measles, mumps, and rubella vaccine, plays a critical role in protecting children and communities from serious infectious diseases. But as misinformation spreads, many parents are left wondering what’s true and what’s not.
Understanding the facts can help you make confident decisions about your child’s health.
“The goal of this vaccine is to prevent diseases that can have serious, even life-altering, effects,” says Susan Scherer, MD, an Atlantic Health pediatrician.
What is the MMR vaccine — and when is it given?
The MMR shot protects against three highly contagious viruses: measles, mumps and rubella:
- Measles is a viral respiratory illness characterized by a high fever, cough, runny nose, red and watery eyes, and a rash. One of the most contagious diseases, it can survive in the air or on surfaces for up to two hours. Key risks with measles include pneumonia, encephalitis (brain swelling) and permanent hearing loss.
- Mumps, a contagious viral infection, causes swelling of the salivary glands. It’s spread through saliva or respiratory droplets from coughing, sneezing or direct contact. Mumps is often mild, but it can lead to severe complications, including meningitis, encephalitis and, in males, infertility.
- Rubella, also known as “German measles,” is a contagious viral infection with symptoms including a fever, sore throat and a rash that starts on the face. Rubella is particularly dangerous in pregnant women because it can cause miscarriage or birth defects.
The MMR vaccine is considered safe and highly effective by health experts. It’s typically given in two doses: The first between 12 and 15 months old, and the second between 4 and 6 years old — typically before starting kindergarten.
Two doses of the vaccine are roughly 97% effective at preventing measles.
Why measles is making a comeback
Thanks to widespread vaccination, measles was declared eliminated in the United States in 2000. But that status is at risk.
Vaccination rates have declined in recent years, dropping below the 95% threshold needed to maintain herd immunity, Dr. Scherer says, noting that national kindergarten MMR vaccine coverage declined from 95.2% in 2019-2020 to 92.7% in 2023-2024.
“When vaccination rates fall, we can’t protect the people around us,” she says. “That’s when outbreaks can start happening again, and we can risk losing our elimination status.”
Debunking MMR vaccine myths
Misinformation is one of the biggest challenges in maintaining protection against measles, mumps and rubella. Dr. Scherer separates fact from fiction:
- Myth: The MMR vaccine causes autism.
Fact: Research has found no link between the MMR vaccine and autism. Dr. Scherer adds, “We don’t see causation with autism or developmental delays.” - Myth: Natural immunity is safer than vaccination.
Fact: Getting vaccinated is far safer than getting sick. No good treatments exist for these infectious diseases, which come with serious risks. - Myth: If others are vaccinated, my child doesn’t need the MMR shot.
Fact: Community protection only works when enough people are vaccinated. “It’s a hidden danger,” Dr. Scherer says. “People don’t see the disease, so they don’t think it’s a risk — but it’s the vaccine that keeps it that way.” - Myth: The vaccine would be safer if it was divided into separate shots for each disease.
Fact: Separate vaccines aren’t available in the United States, and there’s no evidence they’re safer. - Myth: Vitamins or alternative approaches can replace the MMR vaccine.
Fact: Options like vitamin A do not prevent infection.
Why getting vaccinated is still essential
The success of the MMR vaccine has made measles, mumps and rubella less visible, but not non-existent, especially when people are hesitant to get vaccinated.
Vaccination remains the most effective way to prevent the spread of these infectious diseases and protect vulnerable people.
“There aren’t great treatments for these illnesses,” Dr. Scherer says. “They can have lifelong consequences. That’s why prevention is so important.”