Measles surge could strip U.S. of elimination status, experts warn

Large, fast-growing measles outbreaks across the United States have created continuous chains of transmission that experts say may persist beyond 12 months, putting the country at risk of losing its long-held measles elimination status. The Pan American Health Organization is scheduled to review the U.S. designation in April, and public-health officials are racing to determine whether recent clusters are linked or represent separate events.

The technical test for elimination requires a nation to go a year without sustained transmission. Public-health authorities mark the 12-month clock from January 2025, when a prolonged outbreak began in Texas, and investigators are examining whether that chain has seeded subsequent clusters. A separate outbreak has been growing along the Arizona-Utah border, and a fast-moving cluster in South Carolina has added dozens of cases in recent days; state officials reported 58 new cases over a three-day span. A recent CDC update showed 416 confirmed cases in 2026 so far, not counting South Carolina numbers reported after that cutoff.

Case totals for 2025 differ by source as investigators reconcile local and national reports. CDC tallies show 2,144 confirmed cases across 45 jurisdictions and 49 outbreaks in 2025; Johns Hopkins University’s county-level measles tracker recorded 2,724 cases from Jan. 1, 2025, through Jan. 23, 2026. Public-health researchers note that differences reflect update timing and inclusion of provisional reports, and warn that many cases are likely undercounted.

Experts say the resurgence reflects gaps in vaccination and eroding vaccine confidence. “The ongoing outbreak we are seeing in the U.S. underscores the importance of maintaining adequate levels of measles vaccination,” said William Moss, executive director of the International Vaccine Access Center, who co-leads the Johns Hopkins tracker. “The U.S. is at risk of losing its measles elimination status should cases continue at this rate. As vaccine confidence continues to be undermined, immunization is more important than ever to end this outbreak and prevent future outbreaks from occurring.”

Dr. Demetre Daskalakis, an infectious disease specialist and former senior CDC official, framed the situation as a failure of control. “We do not have the capability to actually control measles, whether or not this is demonstrated through continuous measles transmission for 12 months,” he said. “So I’m going to say that elimination is already lost.” Caitlin Rivers, an epidemiologist at Johns Hopkins, added that the erosion of elimination speaks to broader system weaknesses: “It’s really a comment on the state of the public health system… the cycle of panic and neglect.”

Not all officials agree on the interpretation. Dr. Ralph Abraham, CDC principal deputy director, said ongoing transmission linking the Texas outbreak to later clusters “has not been proved,” and argued that losing elimination status would be of limited practical significance: “It’s just the cost of doing business with our borders. We have these communities that choose to be unvaccinated. That’s their personal freedom.” Abraham also reiterated that “vaccination remains the most effective way to prevent measles” and said the agency is available to help.

PAHO’s verification commission will review epidemiological data, genomic analyses and surveillance reports before deciding whether to rescind the U.S. designation. The outcome will be both a technical judgment and a signal about domestic capacity to detect and interrupt outbreaks. Public-health leaders warn that restoring and sustaining high vaccination coverage, strengthening local surveillance and countering misinformation will be essential to prevent a return to the large outbreaks of recent years.