When a single cough can infect 90% of unvaccinated people in a room, you'd think we'd take that disease pretty seriously. Yet here we are in 2026, watching the United States teeter on the edge of losing a public health achievement two decades in the making.

The Measles Comeback Nobody Wanted

The numbers tell a stark story. In 2024, the U.S. recorded 285 measles cases. Concerning, but manageable. Then 2025 hit like a freight train: 2,065 confirmed cases by year's end. That's more than a seven-fold increase in twelve months.

South Carolina bore the brunt of it. The state reported 179 cases throughout 2025, including 20 new infections in just four days between December 27 and December 31. To put that in perspective, South Carolina alone recorded more measles cases than the entire country did in six of the last ten years.

But raw numbers only tell part of the story. Three people died from measles in 2025. Three preventable deaths from a disease we essentially conquered a generation ago. Another 235 people landed in hospitals, with the youngest children hit hardest—one in five kids under age five required hospitalization.

What "Elimination" Actually Means

The word "elimination" gets thrown around loosely, but in public health terms, it has a precise definition. A disease is considered eliminated when continuous transmission stops for more than twelve months. Notice that doesn't mean zero cases. It means no sustained, ongoing spread within the community.

The U.S. declared measles eliminated in 2000. For over twenty years, we maintained that status. Sure, cases popped up—usually travelers bringing the virus from countries where measles still circulates—but these didn't spark sustained transmission. Our vaccination coverage was high enough to snuff out sparks before they became fires.

That's changing. If measles continues spreading for just three more weeks from early 2026, we'll hit twelve consecutive months of continuous transmission. At that point, we officially lose elimination status. It's not just a symbolic loss. It signals that our public health infrastructure has gaps large enough for a highly contagious virus to exploit.

The 95% Threshold We're Failing to Meet

Here's the thing about measles: it's absurdly contagious. If one infected person walks into a room of unvaccinated people, about nine out of ten will catch it. The virus can linger in the air for up to two hours after an infected person leaves.

To stop this kind of transmission, you need what epidemiologists call community immunity—enough vaccinated people to protect even those who can't get vaccinated. For measles, that threshold is 95% coverage. Above that line, outbreaks fizzle out. Below it, the virus finds enough vulnerable hosts to keep spreading.

We've fallen below that line. MMR vaccine coverage among U.S. kindergartners dropped from 95.2% in 2019-2020 to 92.7% in 2023-2024. That seemingly small 2.5 percentage point drop left approximately 280,000 kindergartners at risk during the 2023-2024 school year.

The 2025 case data confirms what those coverage numbers predicted. A staggering 93% of measles cases occurred in unvaccinated people or those with unknown vaccination status. Only 4% had received both recommended MMR doses.

Who's Getting Sick

The demographics of the 2025 outbreak reveal important patterns. The largest group—42% of all cases—were children and teens aged 5 to 19. Another 26% were kids under five, the age group most vulnerable to severe complications. Adults made up 31% of cases, proving that measles isn't just a childhood disease.

Geography tells another story. Measles cases appeared in 44 states and jurisdictions, from Alaska to Alabama, Vermont to Hawaii. This wasn't a localized outbreak that health departments could easily contain. It was a nationwide problem requiring coordinated response across dozens of jurisdictions.

Even in states with high overall vaccination rates, pockets of unvaccinated people created vulnerability. Measles doesn't care about state averages. It exploits gaps wherever they exist.

The Infrastructure That's Supposed to Stop This

Public health infrastructure operates largely invisibly until it's needed. State and local health departments form the front lines of disease surveillance and response. When someone gets diagnosed with measles, local officials spring into action: identifying contacts, checking vaccination records, coordinating with schools and workplaces, sometimes quarantining exposed individuals.

The CDC supports these local efforts by tracking national data, providing technical assistance, and coordinating resources. They update measles case counts weekly, reflecting information as of Tuesday noon each week. This surveillance system allows public health officials to spot outbreaks early and respond quickly.

But infrastructure isn't just surveillance systems and data reporting. It's also the network of vaccination providers, the school immunization requirements, the public education campaigns, and the trust between communities and health authorities. When any part of this system weakens, diseases like measles find their opening.

How We Got Here

Before the measles vaccine became available in 1963, three to four million Americans caught measles annually. Between 400 and 500 died each year. Another 48,000 were hospitalized, and 1,000 developed brain inflammation that could cause permanent damage or death.

The vaccine changed everything. By 1981, reported cases dropped 80% from the previous year. When outbreaks occurred among vaccinated school children in the late 1980s, health officials added a second dose recommendation in 1989. Two doses provide about 97% protection—enough to maintain elimination if coverage stays high.

For two decades, it worked. Then vaccination rates started slipping. Misinformation spread faster than measles ever could. Some communities developed philosophical objections to vaccination. Others faced access barriers—no nearby providers, no insurance, no time off work to take kids for shots.

The COVID-19 pandemic disrupted routine childhood vaccinations globally. Many kids missed scheduled immunizations during lockdowns. Some families developed general vaccine hesitancy. The consequences are playing out now in rising measles cases.

What Elimination Standards Actually Require

Maintaining disease elimination isn't passive. It requires constant effort: high vaccination coverage, robust surveillance, rapid outbreak response, and public trust in health authorities.

The 2025 measles data shows what happens when these elements weaken. Forty-nine separate outbreaks occurred, compared to just sixteen in 2024. Most tellingly, 88% of cases were outbreak-associated, meaning they resulted from sustained transmission chains rather than isolated imported cases.

This pattern—multiple outbreaks, sustained transmission, geographic spread—is exactly what elimination standards are designed to prevent. The twelve-month continuous transmission threshold exists because it distinguishes between occasional sparks (which don't threaten elimination status) and sustained community spread (which does).

The Path Forward Isn't Complicated

Here's the frustrating part: we know exactly how to fix this. The MMR vaccine is safe, effective, and widely available. Two doses prevent measles in 97 out of 100 people. We've done this before—that's how we achieved elimination in the first place.

Getting vaccination coverage back above 95% requires addressing multiple barriers. Some families need better access to vaccination services. Others need accurate information to counter misinformation. Some communities need trusted messengers to explain why vaccination matters.

Public health infrastructure needs sustained funding. Local health departments can't maintain robust surveillance and response capabilities on shoestring budgets. School immunization requirements need consistent enforcement. Healthcare providers need time and resources to counsel hesitant parents.

None of this is revolutionary. It's basic public health practice that worked for decades. We just need to recommit to doing it.

What's at Stake

Losing measles elimination status isn't just about a label. It represents a fundamental failure of public health infrastructure to protect the population from a preventable disease. It means more kids hospitalized with pneumonia and brain inflammation. It means more deaths like the three that occurred in 2025.

It also signals vulnerability to other vaccine-preventable diseases. If measles can circulate continuously, what about pertussis? Mumps? Diseases we've controlled for years could resurge if vaccination coverage continues declining.

The infrastructure that maintains disease elimination—surveillance systems, vaccination programs, public health departments—protects us from threats beyond measles. Weakening that infrastructure has cascading consequences.

A Preventable Crisis

As of early 2026, we're three weeks away from officially losing measles elimination status. That's not inevitable. Aggressive vaccination campaigns, robust outbreak response, and community engagement could still turn things around.

But the clock is ticking. Every day of continued transmission brings us closer to that twelve-month threshold. Every unvaccinated child remains vulnerable. Every community with coverage below 95% provides fuel for outbreaks.

We eliminated measles once through sustained public health effort and high vaccination coverage. We can maintain elimination the same way—if we choose to prioritize it. The alternative is watching a preventable disease reclaim ground we fought decades to win.

The infrastructure exists. The vaccine works. What we need now is the collective will to use the tools we have before we lose an achievement that took generations to accomplish.