Measles Cases Rising in the U.S.: What Families Should Know About Symptoms, Vaccines, and Community Risk

Practical takeaway: Measles is one of the most contagious viruses known. The MMR vaccine remains the most effective way to prevent infection and protect communities. If you or your child develops a high fever and rash—especially after travel or exposure—call a healthcare provider before going in so clinics can take precautions.

By Brian “Weence” Bateman

Measles Cases Are Increasing Again

In recent months, public health officials have reported clusters of measles cases in several U.S. states. According to the Centers for Disease Control and Prevention (CDC), most recent U.S. cases have been linked to international travel or spread in communities with lower vaccination rates.

Measles was declared eliminated in the United States in 2000, meaning there was no continuous year-round spread. However, outbreaks can still occur when the virus is brought in from abroad and spreads among people who are unvaccinated.

While overall case numbers remain far lower than before widespread vaccination, even small outbreaks matter. Measles spreads quickly, especially in schools, childcare settings, and households.

Why Measles Spreads So Easily

Measles is caused by a virus that spreads through the air when an infected person coughs or sneezes. The CDC notes that the virus can linger in the air and on surfaces for up to two hours after an infected person leaves the area.

If one person has measles, up to 9 out of 10 unvaccinated people nearby will become infected. That makes it far more contagious than flu or COVID-19.

Symptoms to Watch For

Measles symptoms typically appear 7 to 14 days after exposure. Early symptoms often include:

High fever (often over 104°F)
Cough
Runny nose
Red, watery eyes

Two to three days after symptoms begin, tiny white spots (called Koplik spots) may appear inside the mouth. A few days later, a red rash usually starts on the face and spreads downward to the rest of the body.

People are contagious from about four days before the rash appears until four days after it begins.

Who Is Most at Risk?

Anyone who is not vaccinated can get measles. Higher-risk groups include:

Infants too young to be vaccinated (under 12 months)
Unvaccinated children and adults
Pregnant people without immunity
People with weakened immune systems

According to the CDC, complications can include ear infections, pneumonia, brain swelling (encephalitis), and in rare cases, death. Young children, especially those under 5, are at higher risk for serious complications.

How Effective Is the Vaccine?

The measles, mumps, and rubella (MMR) vaccine is highly effective. The CDC reports that:

One dose is about 93% effective at preventing measles.
Two doses are about 97% effective.

The standard schedule in the United States is:

First dose at 12–15 months
Second dose at 4–6 years

Adults born after 1957 who do not have evidence of immunity may also need vaccination, particularly before international travel.

No vaccine is perfect, but high community vaccination levels create what public health experts call herd immunity—reducing the chance that the virus can spread to infants and medically vulnerable people.

What to Do If You Think You’ve Been Exposed

If you believe you or your child has been exposed to measles:

Call your healthcare provider before visiting a clinic or emergency department.
Ask about testing and whether post-exposure vaccination may help.
Follow local health department guidance.

Calling ahead helps clinics take infection-control steps to prevent spreading the virus to others in waiting rooms.

Why This Matters for Schools and Communities

Schools, childcare centers, and workplaces may exclude unvaccinated individuals during an outbreak to reduce spread. This can disrupt families and caregivers, especially if quarantine periods extend for weeks.

Communities with lower vaccination coverage are more likely to experience sustained outbreaks. Public health officials emphasize that maintaining high routine childhood immunization rates helps prevent these disruptions.

Oral and Overall Health Considerations

Measles can cause painful mouth sores and increases the risk of secondary infections, including ear infections that may affect hearing. While measles is primarily a respiratory illness, its complications can affect multiple systems, reinforcing the importance of prevention.

What This Means for Readers

If your family’s vaccinations are up to date, your risk is low. If you are unsure about your vaccination status, this is a good time to check your records or speak with a healthcare provider—especially before travel.

Outbreaks tend to occur in pockets, but measles does not stay contained for long when vaccination coverage drops. Staying informed and keeping routine immunizations current remains one of the most effective ways to protect children, vulnerable adults, and the broader community.

This article is for general informational purposes only and is not medical advice. Research findings can be early, limited, or subject to change as new evidence emerges. For personal guidance, diagnosis, or treatment, consult a licensed clinician. For current outbreak or public health guidance, follow your local health department, the CDC, or another relevant public health authority.

Sources

Centers for Disease Control and Prevention (CDC) – Measles (Rubeola)
World Health Organization (WHO) – Measles Fact Sheets