Measles
As of March 6, 2025 the current risk of measles in Marin County is LOW.
Read Public Health Advisory issued March 11, 2025.
What is Measles?
Measles is a childhood disease caused by a virus. It used to be widespread, but now it can almost always be prevented with a vaccine. Also known as rubeola, measles spreads quickly through the air and can be very serious or even deadly for small children. Although more kids are getting vaccinated and death rates are decreasing worldwide, measles still kills over 200,000 people each year, primarily children. Due to high vaccination rates, measles hasn’t been widespread in the United States for about 20 years. Most recent measles cases in the U.S. came from outside the country and happened to people who were unvaccinated or didn’t know if they had been vaccinated. Here is a succinct history of measles.
Why are there Measles Outbreaks in the United States?
Measles outbreaks in the United States are happening for a few reasons:
- Lower Vaccination Rates: Some people are not getting vaccinated or are unsure of their vaccination status. This is partly due to misinformation about vaccines.
- Travel: Travelers from places where the disease is more common can bring measles into the country. Vaccine rates are often lower in these countries, sometimes because of limited access to healthcare.
- Highly Contagious: Measles spreads quickly through the air and can linger in a room for up to two hours after an infected person leaves.
These factors combined have lead to recent outbreaks, especially in areas with lower vaccination rates.
Can a Measles Outbreak Happen in Marin County?
Yes, a measles outbreak can happen in Marin County. In 2015, Marin County had its first confirmed cases when two unvaccinated siblings contracted the disease. California has experienced several measles outbreaks in recent years. 2019, California had 73 confirmed cases, with 41 linked to six different outbreaks. The largest one involved 21 cases at a healthcare facility, showing how quickly measles can spread.
In Marin County, most children entering school are vaccinated, with rates around 99%. This helps protect the community from diseases like measles. But with measles cases rising across the country, it's important to stay vigilant, keep vaccinations up to date, and stay informed.
Why is there a Large Measles Outbreak in Texas?
The large outbreak in Texas, with 146 cases (as of March 3, 2025), including the first measles death in the U.S. since 2015, was driven by decreasing vaccination rates in the region. Vaccine skepticism and hesitancy have grown in many parts of the country due to misinformation and doubts about vaccine safety and efficacy. A 95% vaccination rate is needed to protect against measles outbreaks. The outbreak started in Gaines County, which has a measles vaccination rate of 82%. Texas allows for an exemption from immunizations for reasons of conscience, including religious belief.
About Measles
Rash
Signs and Symptoms
Measles symptoms appear 7 to 14 days after contact with the virus. Common measles symptoms include:
- High Fever (may spike to more than 104° F)
- Cough
- Runny Nose (Coryza)
- Red, Watery Eyes (Conjunctivitis)
- A red rash (characterized by a combination of flat, discolored patches and raised bumps) begins on the face and head a few days after onset of respiratory symptoms and persists for 5-6 days.
Complications
Measles can cause serious health complications, especially in children younger than 5 years of age. Common complications are ear infections and diarrhea. Serious complications include pneumonia and encephalitis, often resulting in hospitalizations. Measles illness during pregnancy increases the risk of premature labor, low-birthweight children, and spontaneous abortion.
Treatment
There is no specific treatment for measles once it happens. Treatment focuses on relieving symptoms and preventing complications. Medications like fever reducers (acetaminophen, ibuprofen, or naproxen) can help manage symptoms. Antibiotics may be prescribed if a bacterial infection like pneumonia occurs. Caution is needed when giving aspirin to children due to the risk of Reye's syndrome. Under direction of a healthcare provider, vitamin A administration may be appropriate. Vitamin A has shown to reduce complications and the risk of death in severe measles cases in children in developing countries where vitamin deficiencies are common due to lack of adequate nutrition.
Protection After Exposure (also called Post Exposure Prophylaxis or PEP)
People without immunity can get protection after exposure. To reduce symptoms, they may receive a measles vaccine within 72 hours or immune serum globulin injections within six days. The MMR vaccine and IG cannot be administered simultaneously. Contact your healthcare provider if you think you have been exposed to a person who has been sick with measles.
Measles Vaccine
Marin County Public Health does not recommend that children aged 6 months to 12 months receive an earlier dose of the measles vaccine unless they are traveling to a region with high measles activity.
The MMR vaccine protects you and your child against three serious viral infections: measles, mumps, and rubella. These infections are highly contagious among people who aren’t vaccinated and cause severe health complications. Children should get two doses of MMR vaccine, starting with the first dose at 12 to 15 months of age and the second dose at 4 through 6 years of age. Teens and adults should also be up to date on their MMR vaccination. Children may also get the MMRV vaccine, which protects against measles, mumps, rubella, and varicella (chickenpox). This vaccine is only licensed for use in children who are 12 months through 12 years of age.
Is MMR a Live Vaccine?
Measles, Mumps, and Rubella vaccines are not recommended during pregnancy or for anyone with a weakened immunce system.
The MMR vaccine is a weakened (attenuated) live virus. That means after you receive it, the viruses cause a harmless infection with few or no symptoms. Then, your body eliminates the viruses. Your immune system fights the disease the weakened viruses cause, and your immunity to the viruses develops.
Is the MMR Vaccine Safe?
The MMR vaccine has some side effects. Reactions can include a sore arm, fever, mild rash, swollen glands, and joint pain. Rare serious reactions include seizures or low platelet count. Adverse reactions should be reported to the Vaccine Adverse Event Reporting System (VAERS). Learn more at the VAERS website.
Why Haven't Vaccines Eliminated Measles?
In 1974, the World Health Organization (WHO) started a global immunization program to reduce illnesses and deaths from vaccine-preventable diseases. Efforts to eliminate measles in the Americas began in 1991 by giving an extra dose of the vaccine to those aged 9-15. In 1998, a false study claimed a link between the MMR vaccine and autism, causing a significant drop in vaccination rates. By 2012, Marin County's kindergarten vaccination rates were at their lowest, 77.9 percent, giving the county a nationwide anti-vaccine reputation. Because measles spreads quickly, maintaining at least 95% immunity is crucial to preventing outbreaks.
Can Vitamin A Prevent Measles?
No. Vitamin A cannot prevent measles, but it can help reduce the severity of the disease. Measles does not have a specific antiviral treatment, but supportive care, including vitamin A administration under the direction of a healthcare provider, may be appropriate. Vitamin A has been shown to reduce complications and the risk of death in severe measles cases in children in developing countries where vitamin deficiencies are common due to lack of adequate nutrition. However, it is not a substitute for vaccination, which remains the most effective way to prevent measles.
Healthcare Provider Information
Testing
Testing for measles can be performed at many commercial laboratories. Please call Marin County Communicable Disease & Community Preparedness at 415-473-4163 if you need any assistance with measles testing.
Reporting
According to Title 17 of the California Code of Regulations, measles is reportable to Public Health. If you are a healthcare provider and have a patient who is suspected or confirmed of having measles, please report it to Marin County Public Health immediately. For more information on Communicable Disease reporting, please refer to our Communicable Disease & Community Preparedness web-page.