The recent measles outbreak in South Carolina, which stands as the largest in the U.S. in decades, has officially come to an end, as state health officials announced on Monday.
Over approximately six months, there were nearly 1,000 confirmed cases, resulting in at least 21 hospitalizations. Fortunately, no new cases have been linked to the outbreak in the last 42 days. This absence of cases marks two complete incubation periods without any reported transmission, according to the state health department.
The outbreak began in October and contributed to a record year for measles in the U.S., coinciding with a significant outbreak in West Texas. The country seems poised for even higher numbers this year, which could result in the worst statistics since the disease was declared eliminated in 2000—a status that is now at risk.
Health experts point to declining vaccination rates as a major factor behind the surge in measles cases. Data shows that over 90% of cases, both in South Carolina and across the nation, occurred among those who had not received the measles-mumps-rubella (MMR) vaccine, primarily affecting children.
However, there are early signs that MMR vaccination rates among young children in the U.S. might be improving.
Some experts speculate that awareness of widespread outbreaks and record numbers of cases might have nudged hesitant parents toward vaccinating their kids, giving rise to “cautious optimism” regarding vaccination trends.
According to public health officials in South Carolina, the increase in vaccination coverage significantly aided in controlling the outbreak.
“Vaccination, along with other solid public health interventions, can be effective even against highly contagious viruses,” remarked Dr. Brannon Traxler, the deputy director and chief medical officer of the South Carolina Department of Public Health, during a news briefing.
In addition to vaccination efforts, thorough contact tracing, investigating cases, and quarantine measures were instrumental in containing the outbreak, even though the response cost the state around $2 million.
The MMR vaccine is proven to be highly effective—about 93% effective with one dose, and that protection increases to 97% with a second dose.
Throughout the outbreak, tens of thousands of MMR doses were given in South Carolina. Notably, doses administered in Spartanburg County, the outbreak’s epicenter, nearly doubled from the previous year, with a statewide increase of 31%. Children under four saw particularly significant rises in vaccinations.
A metric from the CDC indicates that this may align with a broader national trend. In 2025, about 97% of 3-year-olds in the U.S. had received at least one dose of the MMR vaccine, compared to 93% in 2024, according to the CDC’s National Immunization Surveys.
The CDC mentioned that this increase is “consistent with a return to more typical vaccination patterns” following the disruptions in routine care during the Covid-19 pandemic. Notably, it’s been over a decade since MMR coverage among this age group has surpassed 95%, a crucial threshold to prevent outbreaks.
Yet, the sample size for this data is relatively small—averaging about 16,000 children each year—so some experts remain cautious about drawing conclusions, especially since trends in other routine vaccinations haven’t mirrored this positive shift.
Conversely, some believe the uptick in MMR coverage reflects the current environment. “I’ve been saying for a while that it would take a resurgence of vaccine-preventable diseases for people to truly appreciate the benefits of vaccinations,” noted Dr. Josh Williams, a pediatrician focused on vaccination trends.
He added that perhaps there’s a growing recognition among parents regarding the seriousness of these diseases, leading them to ensure their kids are protected in communities where these diseases are spreading.
Dr. Paul Offit, the director of the Vaccine Education Center at the Children’s Hospital of Philadelphia, remarked that widespread transmission had faded from public memory, but recent surges are renewing public awareness. “Now, we’re driven by fear,” he stated, suggesting that anxiety about the disease, coupled with fatigue from anti-vaccine messages, is driving increased vaccination rates.
During recent congressional hearings, U.S. Department of Health and Human Services Secretary Robert F. Kennedy Jr. faced scrutiny regarding his statements and their alleged role in vaccine hesitancy and the resurgence of measles.
Kennedy, however, rebuffed claims of being anti-vaccine, asserting that the recent outbreaks are “unrelated” to his position.
Although the end of this significant outbreak and the rise in MMR coverage generate some hope, experts emphasize that combating measles and other vaccine-preventable diseases remains a continuing challenge.
Current data from the CDC reveals that 1,792 measles cases have already been documented in 2026, with dozens more reported weekly. A particular outbreak along the Utah-Arizona border has escalated to over 600 confirmed cases, with even more suspected. Additionally, there have been at least 22 new outbreaks this year, with four new states reporting cases just in the past week.
South Carolina recorded an additional measles case this month, though it was determined to be unrelated to the larger outbreak. Nevertheless, this case resulted in over 40 exposures.
“We’re definitely not becoming complacent,” Dr. Traxler emphasized. The recent case highlights that measles outbreaks elsewhere continue to pose threats to South Carolina, necessitating vigilance.
Dr. LJ Tan, chief policy officer with immunize.org, remarked that while the findings from the CDC’s survey are promising, it’s premature to conclude it’s part of a larger trend. The situation will become clearer as more data is collected, particularly concerning vaccination rates at critical milestones, like kindergarten entry.
Williams stressed the importance of maintaining the dialogue on vaccination to prevent a drop in rates leading to complacency, stating, “We need to remind families, ‘Remember those measles cases from a couple of years ago?’”
He also indicated that changes in vaccine exemption rates for school attendance could be a significant indicator of shifting attitudes toward vaccination.
Improvement in one vaccine’s coverage doesn’t guarantee similar outcomes for others, Williams cautioned, urging attention to each vaccine’s unique context.
He recently led a study published in JAMA Network Open that showed children who received their first hepatitis B vaccine dose at birth were significantly more likely to complete the series by 18 months than those who did not.
Last year, the CDC officially ceased universal hepatitis B vaccination for newborns, a change prompted by recommendations from members of a federal advisory committee who were influenced by Kennedy.
While the South Carolina health department has yet to assess the uptake of other vaccines similarly to MMR during the outbreak, Dr. Traxler believes the outbreak has enabled providers to engage more with parents about vaccination.
“It would be surprising if those conversations were limited to MMR alone,” she stated in a communication.
The CDC is expected to release fresh data on vaccination coverage among kindergartners in the coming months, providing a more complete view of vaccination trends.
