The measles are popping up again in 2025, and it’s put vaccines back in the spotlight. While Illinois has not have a measles case yet as of late March, it’s still important for parents to stay vigilant, say experts like Jordan Kridler, M.D., a pediatrician.
“Recent measles outbreaks in the United States are due to low vaccination rates,” Dr. Kridler shares. “Since many of these diseases are no longer prevalent, some parents aren’t familiar with them.
“As a result, some parents think the risk of vaccination outweighs the risk of the actual diseases.”
But measles can spread fast and cause more than a fever and rash. Complications send one in five people to a hospital, the Michigan Department of Health and Human Services (MDHHS) notes.
The good news? The measles vaccine is safe and highly effective. Here are answers to a few key questions.
6 key questions about the measles vaccine, answered
1. Why does the vaccine matter?
Measles spreads easily through coughing and sneezing — even lingering in the air for up to two hours. If you’re not vaccinated and exposed, there’s a 90% chance you’ll get it, the MDHHS says.
Vaccines use a weakened virus strain to trigger the immune system, helping the body build antibodies without causing illness.
The measles, mumps and rubella (MMR) vaccine lowers that risk significantly. One dose is 93% effective against measles, and two doses are 97% effective, the CDC reports.
2. How does the vaccine work?
The MMR vaccine protects against three diseases — measles, mumps and rubella. There’s also an MMRV version, which adds chickenpox protection.
Most people who receive two doses will have lifelong immunity, says the CDC.
3. How and when are the shots are given?
Kids typically receive two doses in the thigh or arm:
- Dose 1: at 12-15 months old
- Dose 2: at 4-6 years old
The shots can be given separately, the CDC notes, or with other routine childhood vaccines.
In Illinois, these shots are required for children to start school.
4. Are there side effects?
Most kids have no side effects from the MMR vaccine. If they do, the CDC says they’re usually mild and temporary:
- Soreness or swelling where the shot was given
- Low-grade fever
- Mild rash
5. What if my child is older than 4 — or we’re traveling?
If your child is older and hasn’t been vaccinated, it’s not too late. Older kids, teens and adults without immunity can still get the MMR vaccine, with doses at least 28 days apart.
For international travelers, CDC recommends being fully vaccinated before leaving the country.
And, for infants 6 to 11 months old, it recommends an early dose before travel, with two additional doses given after their first birthday.
6. Where can I get the vaccine?
Your pediatrician, local health department or participating pharmacies can administer the MMR vaccine. The Vaccines for Children Program offers free vaccines for eligible families.
Find out more about what Illinois parents should know about the measles.
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