March 19, 2025 - Tuolumne County, CA – The Tuolumne County Public Health Department (TCPH) is currently investigating suspected cases of measles of two Tuolumne County residents. As part of the investigation, Summerville High School is coordinating closely with Public Health. Public Health officials are actively investigating the suspected cases but would like to proactively advise the public of potential risk of exposure to measles at Summerville High School between the dates of March 10, 2025 and March 11, 2025 and at Adventist Health Sonora Emergency Department during the late evening of March 15, 2025 and early morning of March 16, 2025. This is an emerging situation, details are pending, and we will update the public as soon as further information is available.

Related: Fresno County Recently Confirmed a Case of Measles, Mariposa County Health & Human Services Reports

"Summerville Union High School District takes the health and safety of its students, staff and our community seriously and we will be working closely with Tuolumne County Public Health through the process of identifying any risk to our students, staff and community," states Michael Merrill, Superintendent of Summerville High School.

Public Health would like to advise the public that measles is a highly infectious disease. Exposed individuals should monitor for symptoms and confirm if they have measles vaccination up to date. If they have not had measles in the past and have not yet obtained the measles vaccine, they are at risk of contracting measles if they have been exposed. Unimmunized persons or those with unknown immunization status who were at these locations during the dates and times listed above are at risk of developing measles from 7 to 21 days after being exposed and should monitor for symptoms. Exposed individuals who have been free of symptoms for more than 21 days after exposure are no longer at risk.

People who may have been exposed in the location above around the aforementioned times should:

• • Review their immunization and medical records to determine if they are protected against measles. People who have not had measles infection or received the measles immunization previous may not be protected from the measles virus and should talk with a healthcare provider about receiving measles, mumps, and rubella vaccine (MMR) or Proquad.
• • Monitor themselves for illness with fever and/or an unexplained rash from 7 days to 21 days after their exposure (the time period when symptoms may develop).
• • If symptoms develop, they should isolate at home, and avoid contact with others. Talk to their healthcare provider. Call ahead of their visit to a healthcare facility and make them aware of their measles exposure and symptoms. Public Health can assist healthcare providers in appropriately diagnosing and managing your care.

About Measles

Measles spreads easily through the air when an infected person breathes, talks, coughs, or sneezes. The virus can stay in the air and on surfaces for many hours, even after the infected person has left. The infected person can spread the disease up to four days before a measles rash appears and up to four days after the rash appears. If other people breathe the contaminated air or touch the infected surface, then touch their eyes, nose, or mouth, they can become infected. A person infected with measles can pass it on to others before they feel sick or have symptoms. Young children and those who are pregnant or have weakened immune systems are at a higher risk for life-threatening complications from infection.

Common symptoms for measles include:

• • High fever (higher than 101° F)
• • Cough
• • Runny nose
• • Red and watery eyes
• • Rash 3-5 days after other signs of illness. The “measles rash” typically starts at the face and then spreads down to the rest of the body.

Getting the measles, mumps, and rubella (MMR or MMRV) vaccine is the best way to protect yourself and stop the spread of this dangerous disease. The MMR vaccine protects against three diseases: measles, mumps, and rubella. The MMRV vaccine protects against four diseases: measles, mumps, rubella, and varicella (chickenpox). They are administered in two doses and are highly effective: two doses are 97% effective against measles and one dose is 93% effective. The community spread of measles can be prevented if 95% of individuals in the community have completed vaccination with two doses.

Most health insurances cover the cost of the MMR and MMRV vaccine. Insured persons should check with their doctor or local pharmacy to see what vaccines are offered. Uninsured or underinsured children and adults can access free or low-cost vaccines at clinics enrolled in the Vaccines for Children (VFC) and Vaccines for Adults (VFA) program.

For more information about measles and trends across the state visit: https://www.cdph.ca.gov/.../Pages/Immunization/measles.aspx


Source: Tuolumne County Public Health Department