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The health effects of measles

A doctor examines a smiling girl as a woman looks on.

Dec. 8, 2025—Measles cases are rising in the United States. The virus can make kids very sick for several days—and affect their health even years later. That's worth keeping in mind if you're wondering why you might want to vaccinate your kids.

A highly contagious virus

Measles is spread by respiratory droplets, such as when someone sneezes, coughs or talks. It's so contagious that up to 9 out of 10 unvaccinated people who are around someone with the virus will get it, warns the American Academy of Family Physicians. And, according to the American Society for Microbiology, it can linger in the air for up to two hours.

Most kids recover well from the measles, although the symptoms—for instance, fever, cough and rash—can make them feel miserable. For some, measles can be more serious. According to the National Foundation for Infectious Diseases:

  • About 1 out of every 20 children with measles gets pneumonia.
  • Measles can also cause encephalitis (swelling of the brain).
  • About 1 in 5 people with measles has to be hospitalized due to complications from their illness. And young kids are at higher risk.

Measles can cause lasting damage

Measles can also lead to serious long-term health problems, including immune system and neurological issues. For example:

Immune amnesia. The measles virus can attack memory cells in the immune system. As a result, the immune system may essentially forget how to fight infections, according to the American Academy of Pediatrics (AAP). This leaves kids at risk for other illnesses. Immune amnesia can last for two to three years.

SSPE (subacute sclerosing panencephalitis). This brain disease typically starts 7 to 10 years after a person has measles. It causes progressive (worsening) nervous system problems, such as personality changes and seizures, ending in death. It's very rare—affecting only about 1 in 10,000 people who get measles—but always fatal, the American Academy of Neurology (AAN) reports. It's most likely to affect people with healthy immune systems.

ADEM (acute disseminated encephalomyelitis). This serious and potentially disabling complication involves swelling of the brain and spine that can lead to permanent damage. Some children with ADEM spend weeks in a hospital. About 1 in 1,000 people with measles develop this, usually within weeks of their initial measles symptoms.

Blindness. While measles has been rare in the U.S., in other countries, it causes blindness in about 60,000 children each year, says the American Academy of Ophthalmology (AAO). Most people with measles experience pink eye (conjunctivitis), which goes away on its own. But some get serious infections of the cornea that lead to vision loss. In some cases, measles can affect the optic nerve. And while it's rare, measles can also directly attack the light-sensing cells in the eye, leading to retinopathy. This has happened even years after a measles infection, the AAO reports.

What can you do?

The best way to protect your child from measles and its complications is to get them vaccinated with the measles, mumps and rubella (MMR) vaccine. Children need two doses of the vaccine, says the AAP. The first dose is typically given at ages 12 to 15 months and the second dose at 4 to 6 years. Babies 6 to 11 months old need one dose of MMR before traveling overseas.

Have questions about the MMR vaccine for your child? Your child's doctor is there to help.

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