Measles
UPDATE (August 22nd, 2025): PA DOH Press Release
Measles is a highly contagious respiratory virus caused by the measles virus (MeV). It primarily affects children but can occur at any age. As of early March, 2025, there has been one reported case of measles in Montgomery PA and a total of 222 cases nationally.
What it does...
Measles is one of the most contagious of all infectious diseases; up to 9 out of 10 susceptible persons with close contact with a measles patient will likely develop measles. The virus is transmitted by direct contact with infectious droplets or by airborne spread when an infected person breathes, coughs, or sneezes. Measles virus can remain infectious in the air for up to two hours after an infected person leaves an area.
What to look for...
Measles signs and symptoms appear around 10 to 14 days after exposure to the virus. Signs and symptoms of measles typically include:
- High fever
- Dry cough
- Runny nose
- Inflamed eyes
- Distinctive red rash that typically starts on the face and spreads to the rest of the body
- Tiny white spots with bluish-white centers on a red background found inside the mouth on the inner lining of the cheek — also called Koplik's spots
- A skin rash made up of large, flat blotches that often flow into one another
- Nearly 1 in 5 infected with Measles will require hospitalization, 1 in 20 will get pneumonia and up to 3 per 1000 will die from Measles infection.
Who is at Risk?
Determine if you are protected against measles. Generally, you are considered protected (immune) if you were:
- Born before 1957, or
- Have already had measles, or
- Have received two doses of measles-containing vaccine (usually given as measles, mumps, rubella (MMR) vaccine).
- Look at your vaccination records or ask your healthcare provider to see if you have already had two doses of this vaccine.
- Measles vaccine is routinely recommended for patients 12–15 months with a second dose given at age 4–6 years. Infants under 12 months are not eligible for vaccine and are not protected.
If you are protected from measles, you do not have to do anything. Measles vaccine is extremely effective at preventing measles.
If you are not protected from measles:
- You can choose to be vaccinated. Talk to your healthcare provider to learn how you can get this vaccine.
- Those who are under 12 months of age, pregnant and not immune, or are immunosuppressed (have a weakened immune system) should consult with their healthcare provider as soon as possible. Management of exposure to measles may be different with these conditions.
- Measles is contagious for 4 days before to 4 days after rash starts. If you are not immune and may have been exposed, you could give measles to someone at high risk before developing rash. To prevent that from happening, please wear a mask in indoor public spaces and around anyone who is unvaccinated until 3 weeks after the exposure.
- If you are not immune and may have been exposed, or you develop any symptoms that appear like measles, contact your primary care provider immediately. The early symptoms of measles are fever, runny nose, cough, and puffy, red eyes, followed by rash. Tell your primary care provider that you may have been exposed to measles. You or your primary care provider should notify the state health department at 877-724-3258 if you develop measles symptoms.
For more information about measles, visit the CDC’s webpage on measles.
What Defines an Outbreak?
An outbreak is defined as a chain of transmission including 3 or more cases linked in time and space.