Lead: Measles outbreaks that accelerated in late 2025 remain active and are expected to carry into the new year across multiple U.S. states. Since late summer, clusters centered in southwestern Utah and Mohave County, Arizona, and a growing outbreak in Spartanburg County, South Carolina, have produced thousands of exposures and nearly 2,000 confirmed infections nationally. Local officials report most confirmed cases are among unvaccinated people and that quarantine periods for newly exposed contacts extend through the holidays. Health departments and the Centers for Disease Control and Prevention (CDC) say response efforts are ongoing but differ in scale and visibility across jurisdictions.
- Confirmed national burden: As of the latest CDC update, the United States logged 1,958 measles cases in 2025, 222 (11%) of whom required hospitalization and three deaths reported (New Mexico and Texas).
- State-level counts: Arizona reports 190 cases (mostly Mohave County); Utah reports 125 cases with 21 diagnosed in the last three weeks; South Carolina has 138 confirmed cases since September.
- Quarantine impact: South Carolina has quarantined 168 contacts, primarily schoolchildren; each newly exposed susceptible contact triggers a 21-day quarantine per state guidance.
- Vaccination gaps: Spartanburg County’s K–12 MMR coverage was 90% for 2024–25, under the 95% threshold clinicians cite to prevent sustained outbreaks; NBC News’ Vaccine Divide analysis found 67% of reporting counties below 95%.
- Outbreak count: There have been 49 outbreaks in 2025 (three or more linked cases), with substantial local clustering along the Arizona–Utah border and in Spartanburg County.
- CDC engagement: The CDC’s public-facing social media activity about measles has been lower in 2025 compared with prior years, while federal officials say communication materials have been distributed to states.
Background: Measles is highly contagious and spreads quickly among unvaccinated populations. Historically, the United States saw a record of 2,216 cases in 1992; the 2025 tally is approaching that figure, driven by pockets of low immunization. Public-health experts point to declining MMR coverage in certain communities as a primary vulnerability, compounded by high-contact settings such as schools, clinics and other public venues where exposures occurred. The disease’s incubation and infectious periods mean that identifying a case often triggers multi-week quarantines for susceptible contacts, disrupting schools and household routines during holiday periods.
State and local health departments typically lead outbreak investigations, with the CDC providing technical assistance when requested. Data collection practices for school immunization vary by state and county, so local vaccination percentages can diverge sharply from state averages. Prior outbreaks in the U.S. have followed similar patterns: initial importation or local introduction followed by spread where herd immunity is incomplete. Against this backdrop, public messaging, vaccine access and timely case detection become the key levers to limit further spread.
Main Event: The current wave began in late summer along the Utah–Arizona border, concentrated in Mohave County, Arizona, and nearby southwestern Utah communities. Arizona’s health department reports 190 cases there, with 97% of cases occurring in unvaccinated people; Utah reports 125 cases, including 21 recent diagnoses. More recently, a separate outbreak in Spartanburg County, South Carolina, produced 138 confirmed infections since September, most among unvaccinated school-aged children.
In South Carolina, state epidemiologists described weekly briefings as officials trace contacts and impose quarantine periods. Dr. Linda Bell, the state epidemiologist, explained that each new case with susceptible contacts triggers a fresh 21-day quarantine window, meaning exposed unvaccinated individuals may remain restricted through holiday gatherings. Officials say 168 people in that county are currently under quarantine, limiting school attendance and requiring additional monitoring by local public-health teams.
Public exposures reported in the Utah cluster include an elementary school, an urgent care clinic, a pediatrician’s office and a pediatric dentistry, according to the Utah Department of Health and Human Services. Those settings prompted rapid contact tracing and notifications to families. Health departments emphasize that nearly all infections are preventable with an up-to-date measles-mumps-rubella (MMR) vaccine series and that hospitalizations remain concentrated among vulnerable or unvaccinated patients.
At the national level, the CDC has maintained a lower-profile public communications posture than in some past outbreaks. Academic analysis cited a reduced volume of CDC social-media posts about measles in 2025 compared with previous years. Federal officials responded by saying updated, multilingual materials were provided to support local responses, while noting CDC deployments to states occur upon request.
Analysis & Implications: The outbreaks expose how subregional declines in vaccine coverage can erode community protection even when statewide or national averages appear adequate. A 95% MMR coverage threshold is commonly cited to prevent sustained transmission; pockets with coverage near 90% or lower create chains of susceptible individuals where measles can reestablish itself. In practical terms, this means schools, clinics and other child-centered venues become amplification points when a case is introduced.
Health-system impacts are also notable: with 11% of reported cases hospitalized in 2025, outbreaks strain inpatient pediatric and infectious-disease capacity in affected counties. Hospitalization rates reflect complications such as pneumonia and dehydration that can accompany measles, and they increase clinical and public-health costs. For families, quarantines that last weeks impose economic and educational burdens, amplifying the social cost of preventable outbreaks.
Policy implications include renewed focus on improving localized immunization coverage, standardizing school-entry reporting and augmenting vaccination outreach in communities with persistent hesitancy or access barriers. If local vaccine uptake does not increase, public-health authorities warn further waves are likely. International travel and sporadic importations continue to present seeding events for susceptible pockets, so both border- and community-focused strategies are relevant.
| Jurisdiction | Confirmed cases (2025) | Notable metric |
|---|---|---|
| United States (total) | 1,958 | 222 hospitalizations; 3 deaths |
| Arizona (mostly Mohave County) | 190 | 97% unvaccinated |
| Utah | 125 | 21 cases in last 3 weeks |
| South Carolina (Spartanburg County) | 138 | 90% K–12 MMR coverage (2024–25) |
The table summarizes publicly reported counts and key metrics from state and federal updates; local case totals and vaccination percentages reflect the most recent releases from state health departments and NBC News’ Vaccine Divide investigation. Numbers are subject to revision as agencies update their databases during ongoing investigations.
Reactions & Quotes:
“As we identify new cases, and if those cases have susceptible contacts, that’s a new 21-day quarantine period,”
Dr. Linda Bell, South Carolina State Epidemiologist (state public-health briefing)
Bell’s statement underscores how each newly identified case can reset quarantine timelines for exposed unvaccinated people, prolonging disruption for schools and families through holiday periods.
“The CDC has developed and distributed updated communication materials, including multilingual resources, to help communities respond to ongoing outbreaks,”
Andrew Nixon, Department of Health and Human Services spokesman (email)
Federal spokespeople framed the agency’s role as providing content and technical assistance while noting that field deployments occur when state health departments request them.
“Nearly all cases in these clusters are among people who were not vaccinated,”
State health department releases (Arizona, Utah)
State statements emphasize the connection between vaccine status and infection risk, which public-health officials are using to target outreach and vaccination clinics in affected communities.
Unconfirmed:
- Whether the South Carolina outbreak has seeded undetected transmission in neighboring North Carolina; state officials have reported no evidence so far.
- Whether additional federal CDC field teams will be requested by states beyond current technical support; deployments are made upon state request and may change.
- Exact final case counts for late-reporting exposures over the coming weeks; public databases are periodically updated as investigations close.
Bottom Line: The 2025 measles situation highlights that localized declines in vaccination coverage can quickly translate into sizable outbreaks, even when national averages appear better. With nearly 2,000 cases reported and clusters concentrated where MMR coverage is below the 95% threshold, public-health responses will need to combine targeted vaccination drives, careful contact tracing and clear communication to break transmission chains.
For communities, the urgent priorities are increasing timely MMR uptake among children and adults who lack documented immunity, reducing exposure opportunities in high-contact settings and supporting families through quarantine requirements. Nationally, consistent data reporting and coordination between state and federal agencies will affect how rapidly these outbreaks are contained and whether case counts climb further into the new year.
Sources:
- NBC News — original reporting and Vaccine Divide analysis (media)
- Centers for Disease Control and Prevention — national case updates (federal public health)
- Utah Department of Health and Human Services — state outbreak notices (state public health)
- Arizona Department of Health Services — state reports (state public health)
- South Carolina Department of Health and Environmental Control — state briefings (state public health)