Measles Update

As of March 20, 2025, the Centers for Disease Control and Prevention had reported 378 measles cases across 18 states. Most of these cases are associated with three outbreaks, the largest being in Texas. Of all cases, 75% have been reported among unvaccinated children and young adults up to age 19.

On Tuesday, March 11, the Los Angeles County Department of Public Health reported the county’s first measles case of the year. 

Measles is caused by a virus and is extremely contagious with transmission in a community becoming likely if vaccination rates fall below 95%. Measles is spread by droplets (that can linger in the air for 2 hours) and by contact with contaminated surfaces. Protection by a vaccine is very effective (93% after 1st dose, 97% after 2nd dose). High risk of measles is present in healthcare settings, college campuses, international travel, and close contact with immunocompromised people.

Historically, the following vaccines were given in USA:

Other important notes:

- Getting an MMR booster is very low risk for people with intact immune systems.

- Babies are protected with maternal antibodies until 6-12 months of age.

- In an outbreak, babies 6+ months of age need additional protection from an MMR vaccine assoon as possible, however since their immune system is still immature, this early dose doesn’tlast and would not count toward their two-dose series.

Check with your health provider if you have questions.

I would also encourage everyone to follow Dr. Katelyn Jetelina, MPH, PhD at yourlocalepidemiologist@substack.com for more information and health updates.

If you need a Measles vaccination please contact us for an appointment.