Officials are tracing contacts in Sacramento and Placer counties as California’s 2026 measles count keeps rising.
SACRAMENTO, Calif. — Sacramento County said Monday that two more unvaccinated children have measles, lifting the county’s recent total to five and extending a Northern California outbreak that has spread into neighboring Placer County while California’s case count keeps climbing.
The new cases matter because they show the virus is still moving through the Sacramento region more than a month after county officials first disclosed infections on March 4. Health departments in Sacramento and Placer counties are now tracing contacts across clinics, waiting rooms, family networks and community gatherings, while the California Department of Public Health has continued to add confirmed cases to its statewide total. Officials have not publicly mapped every transmission link, and they have said some infections may still have gone undetected.
Sacramento County’s first public notice came on March 4, when officials said two unvaccinated children had measles. One child had contracted the virus in January while traveling in South Carolina, where a large outbreak was underway, and the source of the second child’s infection was unknown. The second child later received care at Kaiser Permanente Roseville Medical Center on March 2 between 6:55 a.m. and 7:14 a.m., creating an exposure window that forced the hospital and county staff to identify patients and workers who may have been in the area. Dr. Olivia Kasirye, Sacramento County’s public health officer, said then that measles is highly contagious and can be brought back into the community through travel. By the next day, Placer County said three teenagers in one family had measles and a fourth family member was suspected to be infected, with officials linking that household to an extended relative who had traveled to South Carolina.
What first looked like a contained family cluster has since widened. Sacramento County said it was notified on April 1 about two additional measles cases in unvaccinated children. Both children were placed in isolation and were recovering, while public health teams worked with clinics and emergency departments across the region to notify anyone who may have been exposed. On April 7, Placer County said the outbreak in that county remained at eight known cases and warned that more may not yet have been detected. County officials listed a possible public exposure at Sweetpeas restaurant in Auburn on March 29, and said they were also directly notifying people tied to emergency department waiting rooms and a home birthday party in Auburn. Dr. Rob Oldham, Placer County’s health officer, said the pattern now points to at least some community spread. Nearly all of the cases identified in Placer County have had some connection to homeschool enrichment programs in the region, either directly or through relatives.
The Sacramento and Placer cases are part of a broader measles year in California. State officials had reported 26 confirmed cases in nine counties as of March 2, when Sacramento announced its first two cases. Sacramento County’s April 6 update said the state had counted 34 confirmed cases through March 30. By noon on April 6, the California Department of Public Health’s measles page showed 35 confirmed cases statewide. The state has also been dealing with outbreaks outside the capital region. In Shasta County, where the first case of that outbreak was identified Jan. 30, health officials said this week that a suspected 10th case was ruled out and the outbreak ended on March 30 with a final count of nine. Earlier in the year, state officials also said two infectious measles patients had visited Disneyland on Jan. 22 and Jan. 28, a reminder of how quickly a single imported infection can create concern in crowded public spaces.
The California numbers are unfolding against a much larger national surge. The Centers for Disease Control and Prevention said on April 3 that the United States had recorded 1,671 confirmed measles cases as of April 2 across 33 jurisdictions, with 94% linked to outbreaks. California’s overall school vaccination levels remain stronger than the national average, but state officials have repeatedly warned that statewide averages can hide smaller clusters where measles can move fast once it gets in. In a 2025 immunization report, the state said measles, mumps and rubella coverage among California kindergarteners remained above 95% and stood at 96.2% for the 2023-24 school year. The same state report showed wide county variation and said 16 counties were below the 95% level for kindergarten MMR coverage. That gap helps explain why public health officers can describe the risk to the broader public as low while still warning that certain family or school networks may be more vulnerable.
The public health response has followed a familiar but time-consuming pattern. Counties have isolated sick patients, traced close contacts, warned hospitals and clinics, and coordinated with state officials to decide which infections belong to the same outbreak. Kaiser Permanente Roseville Medical Center told Sacramento County it had put infection control measures in place once measles was suspected in the child seen there on March 2. Placer County said some later cases generated no new public exposure notices because those individuals had already been asked to quarantine. On March 11, Placer officials said they were trying to notify up to 165 attendees of an enrichment program who may have been exposed. On March 25, the county announced four additional cases in the same household as an earlier patient, again saying there were no new public exposure sites because those people had already been told to stay home. As of April 8, counties were still sorting out whether the newest Sacramento infections were directly tied to earlier cases, to the Placer cluster, or to a separate chain that has not been fully mapped.
Much of the outbreak work has taken place out of view, in call logs, patient lists and exposure windows attached to ordinary places. A hospital waiting room in Roseville, a restaurant in Auburn, a birthday party at a home, and an enrichment program serving children have all become part of the same regional investigation. Officials have tried to balance concern with reassurance as those details emerge. Kasirye said this week that the continued identification of measles cases in the community shows how quickly the disease can spread. Oldham said Placer residents who are not vaccinated should understand that the current risk is higher than it was when the outbreak appeared to be limited to one extended family. Even so, local officials have avoided describing the situation as a countywide emergency. Their updates have instead emphasized targeted notifications, isolation of known cases and the slow work of determining whether each new infection broadens the outbreak or fits within a chain they already understand.
As of Wednesday, Sacramento County continued to list five recent confirmed cases and Placer County continued to list eight linked to its outbreak. The next public measure of the outbreak will be whether the late March exposures and the April 1 Sacramento cases lead to new confirmed infections in the next round of county and state updates.
Author note: Last updated April 8, 2026.