US loses measles elimination status as deaths and cases hit worst levels since 1991

The United States has lost its official measles elimination status, a source told CNN — a designation the country held for 26 years and earned through one of the most sustained vaccination campaigns in public health history. This development coincides with the country's deadliest and most widespread measles year since 1991: ten measles-associated deaths have been recorded so far in 2026, five of them in just the last two weeks.

An independent expert committee appointed by the Pan American Health Organization — the body now responsible for assessing elimination status — met this week in a closed-door session to evaluate whether the US has seen sustained local measles transmission for at least 12 consecutive months. That threshold, once crossed, means measles is once again endemic in the country. According to CNN, the committee concluded it has been.

From January 2025 through November 13, 2026, US states have reported 5,412 measles cases, according to KFF. The outbreak began in early 2025, centered in Texas, and spread to multiple states. Among the 2,288 confirmed cases in 2025 alone, 243 — 11% — were hospitalized and three deaths occurred. The toll has grown sharply in 2026.

It's really tragic and unnecessary, and it's all completely preventable. Two doses of vaccine, which is highly safe and effective, will essentially limit the number of cases in the US, and we're just throwing that away.— Dr. Yvonne Maldonado, pediatric infectious diseases expert, Stanford University

Measles is the most contagious disease known. When spreading through a population with no prior immunity, one case can produce 12 to 18 further cases, according to KFF. Health complications occur in roughly 30% of infections, and around 1 in 1,000 infections leads to death. Beyond the immediate illness, measles can cause lasting damage to the immune system, leaving those who survive — particularly children — more vulnerable to other infections.

The vaccine that made elimination possible has been available since 1963. Two doses of a measles-containing vaccine are estimated to be 97% effective at preventing infection, according to KFF. Epidemiologists set 95% population coverage as the threshold for herd immunity — the point at which transmission is interrupted and large outbreaks cannot take hold. The US is well below that mark: national two-dose MMR coverage among children entering kindergarten in 2025 was 92.4%, down from 94.7% in 2011. In Idaho, coverage stood at just 75.2%. Only 10 states reported coverage at or above 95%.

The road to elimination was long. The US first set a national goal to interrupt measles transmission in 1966, just three years after the first vaccine was licensed. Further elimination goals were announced in 1978 and 1993. It was not until March 2000 that an external panel convened by the CDC's National Immunization Program reviewed the epidemiological data and officially declared measles eliminated — meaning no sustained endemic transmission had occurred for more than a year. The status was re-verified in 2012 by a separate expert panel.

This achievement is a credit to the efforts of millions of parents and children, hundreds of thousands of health workers, and thousands of policy makers and legislators who provided the political and financial support.— Expert committee members, writing in the Journal of Infectious Diseases, May 2004

Notwithstanding the tremendous progress that has been made, it is critical to understand that this is an inherently unstable situation and that we must maintain (and improve) our efforts to ensure that immunization levels remain very high and that surveillance is of high quality.— Expert committee members, writing in the Journal of Infectious Diseases, May 2004

That warning proved prescient. Outbreaks recurred in 2018–2019, with more than 1,200 cases, according to KFF. Then, beginning in early 2025, a far larger resurgence took hold — driven by falling MMR coverage linked to the COVID-19 pandemic and rising vaccine hesitancy, compounded by funding and staffing cuts at the federal, state, and local levels that hampered prevention and response efforts, according to KFF.

Federal leadership has also complicated the response. HHS Secretary Robert F. Kennedy Jr. has repeatedly questioned whether the MMR vaccine is safe and effective. In his role leading the nation's top health agency, he has pursued a reduction in the number of childhood immunizations the federal government recommends, established a federal program centered on vaccine injuries, and given a keynote address to a conference organized by a group that opposes vaccines, according to CNN. KFF notes that mixed messages from federal officials have contributed to increased public skepticism about vaccine safety and a decline in trust of health authorities.

We have now bred a whole culture of denial of the impact of measles and elevated vastly overstated, active disinformation about the safety of the measles vaccine.— Dr. Yvonne Maldonado, pediatric infectious diseases expert, Stanford University

CDC Director Dr. Erica Schwartz told CNN in November that even a loss of elimination status would not prompt the agency to overhaul its approach to outbreak response.

Public health experts who worked toward the original elimination say the conditions for recovery are far more difficult now than they were in 2000. Trust in public health and in science broadly remains low, still damaged by the COVID-19 pandemic. The epidemiology has also shifted: immune protection is lagging not just among children but in pockets of adults — a complication that did not exist during the original push toward elimination, when the adult population had acquired natural immunity by contracting measles as children.

When we started toward elimination, we had an immune adult population because they'd all gotten it as kids, so we only had to focus on vaccinating the cohort of children. The way in which we're trying to tackle it is going to have to be very different.— Janet Hamilton, executive director, Council of State and Territorial Epidemiologists

Regaining elimination is going to be harder for us than it was the first time.— Janet Hamilton, executive director, Council of State and Territorial Epidemiologists

When large outbreaks occurred in the past, the federal government answered with presidential initiatives, new funding, and policy shifts — among them the Vaccines for Children Program and the National Childhood Immunization Initiative, both of which pushed school vaccine mandates and other state-level laws aimed at achieving mass immunization, according to Dr. Walter Orenstein, who led the CDC's National Immunization Program.

In the past, we had presidential initiatives which focused on providing resources as well as being major advocates to take actions to get rid of the measles. We've not seen that in this time.— Dr. Walter Orenstein, former head, CDC National Immunization Program

The path back to elimination status is defined: the US must demonstrate that outbreak transmission has been interrupted for at least 12 consecutive months. But with vaccination rates below the herd immunity threshold in most states, a public health system that is less funded and less resourced than in previous decades, and federal officials sending mixed signals on the vaccine that made elimination possible in the first place, experts say the clock on that 12-month window has not yet begun to run.

Why it matters — Losing measles elimination status means the US has returned to a baseline of endemic disease spread — and experts warn that rebuilding the vaccination rates and public trust needed to regain that status will be harder than achieving it the first time.

Reported by cfr.org, cnn.com, kff.org