South Carolina Measles Outbreak Reaches 789 Cases as New ACIP Chair Questions Vaccine Mandates

The measles outbreak centered in South Carolina has now reached 789 confirmed cases, making it the largest single outbreak in the United States in more than three decades. The surge comes as the newly appointed chair of the Advisory Committee on Immunization Practices has publicly suggested that childhood vaccinations should be optional rather than required — a stance that public health experts warn could further erode immunization rates.

An Outbreak Fueled by Undervaccination

The outbreak, which began in late 2025 in a community with low vaccination rates in the Upstate region of South Carolina, has now spread to multiple counties. State health officials have confirmed that the vast majority of cases involve unvaccinated children, with several dozen hospitalizations and at least two deaths in children under five.

Measles was declared eliminated from the United States in 2000, meaning there was no sustained domestic transmission. But pockets of undervaccination — driven by vaccine hesitancy, misinformation, and in some cases philosophical or religious exemptions — have created communities vulnerable to imported cases.

The MMR (measles, mumps, rubella) vaccine is approximately 97% effective after two doses. The Centers for Disease Control and Prevention recommends that children receive the first dose at 12–15 months and the second at 4–6 years. National coverage has fallen below 93% for kindergartners, dropping below the threshold needed for herd immunity in many communities.

A New Direction at ACIP

The timing of the outbreak has amplified concerns about a shift in federal vaccine policy. The new ACIP chair, appointed by the administration in January, told reporters that vaccines should be "available and recommended but not mandatory" and suggested that parents should have "full autonomy" over childhood immunization decisions.

ACIP is the expert panel that recommends which vaccines Americans should receive and at what ages. While its recommendations are not themselves mandates, they form the basis for state school-entry vaccination requirements and insurance coverage decisions.

Former ACIP members and public health leaders have expressed alarm. "This is not a theoretical policy debate," said one former committee member. "We are watching in real time what happens when vaccination rates fall below critical thresholds."

Meanwhile, Life Expectancy Hits a Record

In a more encouraging development, provisional data from the National Center for Health Statistics shows that U.S. life expectancy has reached a new record high of 79.4 years, continuing a recovery from the COVID-19 pandemic lows. The improvement was driven by declines in mortality from heart disease, cancer, and COVID-19 itself [1].

The divergence is striking: even as overall health indicators improve, the measles outbreak underscores how quickly gains in infectious disease control can reverse when vaccine confidence erodes.

The Shingles-Dementia Connection

In other health news, a large observational study published this week in Nature Medicine found that adults who received the Shingrix shingles vaccine had a significantly lower risk of developing dementia over a seven-year follow-up period compared to those who received an older, less effective shingles vaccine [2].

Researchers cautioned that the study was observational and cannot prove causation, but the finding adds to a growing body of evidence suggesting links between viral infections, inflammation, and neurodegenerative disease. Clinical trials to test whether Shingrix directly reduces dementia risk are now being planned.

What Comes Next

South Carolina Governor Henry McMaster declared a public health emergency last week, freeing up state resources for vaccination clinics and case tracking. The CDC has deployed additional epidemiologists to the state.

But the political dynamics remain complicated. With the new ACIP leadership signaling a more permissive approach to vaccination policy, state-level mandates may face increased scrutiny — even as the South Carolina outbreak demonstrates their public health rationale.