Measles Explained: Updated Facts, Vaccination Tips, and How to Stay Safe

Measles is not just a childhood illness—it is a highly contagious virus that poses serious health risks for unvaccinated individuals of all ages. Measles, once declared eliminated in the United States in 2000, is making a concerning comeback. As of May 4, 2025, in the current measles outbreak in the United States, over 930 confirmed cases of measles have been reported across more than 30 states—including a recent case involving an Illinois resident (CDC, 2025). This increase in measles cases is largely attributed to declining vaccination rates and increased national and international travel.

As measles cases reappear in communities, understanding the symptoms, how the virus spreads, and how to protect yourself and your family is essential.

What Is Measles?

Measles is a viral illness caused by the measles virus. It primarily affects the respiratory system (lungs, nose, mouth and the airways connecting them). Once infected, the virus can cause the following symptoms, which usually appear 7-14 days after exposure:

High fever (often >104°F)

Cough

Runny nose

Red, watery eyes

A red rash that usually starts on the face and spreads downward

Small white spots inside the mouth (Koplik spots)

Though often dismissed as a childhood illness, measles can lead to serious complications, particularly in young children, pregnant individuals, and people with weakened immune systems. These complications include pneumonia, brain swelling (encephalitis), and even death (World Health Organization [WHO], 2023).

How Measles Spreads

Measles is one of the most contagious diseases known to humans. The virus spreads through tiny droplets in the air that are released when an infected person coughs or sneezes. These droplets can remain in the air for up to two hours, which means you can become infected without direct contact with the sick person.

A person with measles is contagious from four days before to four days after the appearance of the rash (CDC, 2024).

Prevention: How You Can Protect Yourself and Others

The most effective protection against measles is the MMR vaccine (measles, mumps, rubella).

The CDC recommends two doses:

The first dose at 12 through 15 months of age

The second dose at 4 through 6 years of age

Adults born after 1957 who have not had measles or the vaccine should receive at least one dose, and two if they are at higher risk (e.g., healthcare workers, international travelers).

Two doses of the MMR vaccine are about 97% effective at preventing measles infection (CDC, 2023).

Key prevention tips:

Ensure you and your family are fully vaccinated.

Avoid travel to areas experiencing outbreaks if you are unvaccinated or immunocompromised.

If someone in your household is ill, practice good hygiene and separate them from others as needed.

If exposed, contact your healthcare provider immediately, especially if you are pregnant, have a weakened immune system, or are unsure if you are fully vaccinated for measles.

What To Do If You Have Been Exposed

If you believe you’ve been exposed to measles:

Contact your doctor or local health department right away before going to a healthcare facility to avoid exposing others.

Monitor for symptoms for 21 days after exposure.

If you’re not immune, your doctor may recommend a dose of the MMR vaccine or immune globulin to reduce the risk of infection and severe complications.

Public Health Officials Need Your Help

If your local or state health department contacts you, it may be as part of a case or outbreak investigation. Cooperation is important to helping prevent further spread. You may be asked about:

Places you have visited (e.g., restaurants, hotels, grocery stores, church, etc.)

Your vaccination status

People you’ve been in close contact with

Answering these questions accurately and honestly helps protect your community—especially vulnerable individuals who cannot be vaccinated due to medical conditions.

Everyone Has a Role In Protecting Public Health

Measles is a preventable disease with a proven and safe vaccine. But prevention only works if communities understand the importance of immunization, early detection, and working closely with public health officials.

As measles reemerges, it’s important to remember that one person’s actions—such as staying up to date on vaccinations—can have ripple effects that protect entire communities.

If you have questions about measles or need help determining your vaccination status, contact your healthcare provider or your local or state health department for guidance.

References:

Centers for Disease Control and Prevention (CDC). (2024). Measles cases and outbreaks. https://www.cdc.gov/measles/cases-outbreaks.html

World Health Organization. (2023). Measles. https://www.who.int/news-room/fact-sheets/detail/measles

Dr. Frederick Echols, MD, is available as a subject matter expert on public health for press interviews and speaking engagements.

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About Dr. Fredrick Echols, MD

Dr. Fredrick L. Echols, MD is the founder and Chief Executive Officer of Population Health and Social Justice Consulting, LLC, an Obama Foundation Global Leader, sought-after public speaker, black men’s health advocate, and accomplished physician with over 15 years of experience in public health. He has worked extensively with public and private sectors to address complex health issues through evidence-informed approaches. Dr. Echols is a graduate of the Centers for Disease Control and Prevention Population Health Training in Place program and the ASTHO-Morehouse School of Medicine’s Diverse Executives Leading in Public Health program.

Passionate about health and justice, Dr . Echols’ notable roles include serving as Chief Executive Officer for Cure Violence Global, Health Commissioner for the City of St. Louis, and Director of Communicable Disease and Emergency Preparedness for the St. Louis County Department of Public Health. In these roles, he oversaw public health regulations, led COVID-19 response efforts, managed daily operations, and developed strategic partnerships. Dr. Echols also served as Chief of Communicable Diseases for the Illinois Department of Public Health and as a physician in the U.S. Navy. He continues to contribute to public health research and guides health organizations globally.