The MMR vaccine protects against measles, mumps, and rubella. Measles in particular is one of the most contagious infections known, and before the vaccine it killed hundreds of children a year in the U.S. The vaccine is one of the most studied in medicine.

What it protects against

Measles (highly contagious respiratory illness that can cause pneumonia and encephalitis), mumps (swelling of the salivary glands, can cause meningitis and hearing loss), and rubella (mild in kids but devastating to a developing pregnancy).

When it’s given

Per the CDC schedule: first dose at 12-15 months, second dose at 4-6 years. Kids can get the second dose earlier (as early as 4 weeks after the first) if traveling internationally or during an outbreak.

Common side effects

Soreness at the injection site, low-grade fever 1-2 weeks after (when the virus replication peaks), sometimes a mild rash. Febrile seizures are a known but rare reaction, most often with the first dose in toddlers.

Common questions

The MMR-autism link has been studied extensively and no causal relationship has been found — the original paper claiming a link was retracted and its lead author lost his medical license. We’re not here to preach; if you have specific questions, your pediatrician has the time to walk through them. Spacing the MMR from other vaccines isn’t recommended on medical grounds but some practices will accommodate it.

Questions worth asking

How VisitRecall fits in

Track which dose was given when, and any reaction, on one timeline with the health journal and parents hub.

FAQ

Can I space MMR from varicella?

Yes — MMR and varicella can be given separately or as combined MMRV. Combined has a slightly higher febrile seizure rate in toddlers for the first dose, so some practices prefer them separate at 12 months.

What if my kid had a cold on vaccine day?

Mild illness is usually fine. High fever would typically delay.

One dose or two?

Two doses reach 97% effectiveness against measles. One dose is about 93%.