Thanks to widespread vaccination, measles had been considered “eliminated” as a continually transmitting illness in the United States since 2000 – but not anymore. An independent commission of experts that reports to the director of the Pan American Health Organization determined that the U.S. no longer qualified as having eliminated measles, a source close to the process told CNN on Friday. The news was first reported by The Wall Street Journal. The decision was widely expected after years of falling vaccination levels and surging case counts, but it’s still a black mark on the nation’s public health policy. The international committee that determines countries’ measles elimination status considers an infection to be endemic, or regularly occurring, if infections caused by the same strain are passed from person to person for at least a year within the same country. To determine this, the committee members look at the genetic code of viruses sampled from patients. Every time a virus copies itself, it makes tiny changes in its genetic code. By studying the genomes of different viruses in an outbreak, scientists can determine how closely the infections may be related and whether they are likely to have been part of the same chains of transmission. In August, scientists with Utah’s public health laboratory published a preprint study showing that the same strain of measles had been circulating in the state for more than a year, accounting for more than 95 per cent of cases there. It travelled from the southwest part of the state to central Utah, ultimately causing more than 600 cases between June 2025 and June 2026. There have also been sustained outbreaks in South Carolina, Pennsylvania, Wisconsin and New York, as well as other states. It’s not clear what data the committee relied on to make its decision, but it wasn’t exactly a tough call, said Dr. Angela Rassmussen, a virologist at the University of Saskatchewan in Canada and Editor-in-Chief of the journal Vaccine. The Utah data alone would have been enough to make the case, she said. The U.S. has logged record numbers of measles cases, hospitalizations and deaths for the past two years, even as some members of the Trump administration – including President Donald Trump – have cast doubt on the safety and effectiveness of the vaccines that prevent it. “Measles elimination is a vital sign for our public health system. It shows cracks in our foundation. Losing elimination status means that we are less prepared as a nation to address infectious and noninfectious disease challenges,” said Dr. Demetre Daskalakis, former director of the National Center for Immunization and Respiratory Diseases at the U.S. Centers for Disease Control and Prevention. The measles-mumps-rubella (MMR) vaccine is so effective that two doses cut an exposed person’s chances of getting sick by 97 per cent compared with someone who is unvaccinated. Since 2000, when measles was declared eliminated in the United States, the country has still some outbreaks every year. These were touched off by sick travelers who brought the virus into the country. Because of community protection maintained by high vaccination rates, these outbreaks were usually small and short-lived. In 2025 and 2026, however, the virus found more families and communities that were unvaccinated, leaving them vulnerable to infection. More than 5,400 measles cases have been reported in the US this year – the highest number since 1991. Most are linked to the 43 new outbreaks this year, but more than 1,000 cases are linked to outbreaks that began last year. Nearly all of this year’s cases have been in people who had not received the MMR vaccine or whose vaccination status is unknown. People have been hospitalized in roughly one in 9 reported cases, according to the CDC, and at least 10 people have died after catching measles, according to state reports. ‘Measles is back’ The declaration is a humbling moment for a nation that played a leading role in ridding the world of smallpox – the only human disease to have ever been wiped out worldwide – and worked for decades to drive measles offshore. “This is just so devastating and so sad that we are where we are today,” said Dr. Nuwan Gunawardhana, an infectious disease epidemiologist at Columbia University Irvine Medical Center in New York. “This just kind of points towards the direction of really reversing a generation of public health progress.” But it also means people who are too young to be vaccinated against measles or who have lowered immune function because of organ transplants or cancer or other conditions are at higher risk in areas with outbreaks than they were just two years ago. Most people who get measles will recover after having a fever and a rash and feeling generally miserable for several days, said Dr. William Moss, a professor and measles expert at the Johns Hopkins Bloomberg School of Public Health. But that doesn’t mean the infection is benign, he said. Measles can also wipe out a person’s immune memory. The immune system forgets which infections it’s fought off before, leaving the person vulnerable to secondary threats like pneumonia or diarrhea. If a pregnant woman catches measles, she can pass it to her baby in the womb, and the baby will be born with measles, putting its life at risk. In rare cases, people who’ve had measles can develop serious neurologic complications, sometimes years after the original infection. The most serious is subacute sclerosing panencephalitis, or SSPE, which is progressive and fatal. All of these complications can be prevented by vaccination. The United States losing its measles elimination status is “incredibly embarrassing,” said Dr. Peter Hotez, co-director of the Center for Vaccine Development at Texas Children’s Hospital in Houston. But, he said, it’s a signal of an more important message: “Basically, measles is back.” “Whether or not we’ve officially lost our elimination status to me is much less important than, basically, measles is here. It’s pervasive, and vaccination rates are down across the country, and I don’t see us getting back to normal anytime soon,” he added. Could the U.S. regain its elimination status? Measles is one of the most contagious viruses known to science. A single infected person typically spreads it to 12 to 18 others. The virus is airborne and can float in a room for hours after a sick person leaves it. Soon after the measles vaccine was deployed in the early 1960s, public health experts realized that if enough people in an area were vaccinated, the protection from the shot could stop the spread of the virus. The US set its first goal to eliminate measles transmission in 1978. Measles is one of the 30 diseases targeted for elimination by 2030 by the Pan American Health Organization, or PAHO. In 2016, PAHO and the World Health Organization declared the 35 countries in the Americas region to be free of ongoing measles transmission. That designation was lost last year, however, when Canada’s elimination status ended after a lengthy outbreak that spanned several provinces. Mexico, which has had several large measles outbreaks of its own, is also in danger of losing its elimination status. Moss said that since the US has lost its measles elimination status, it has to be on the path to regaining it. “That’s not easy, particularly in the current environment with diminished public trust in vaccines, the increasing nonmedical exemptions that we’re seeing in schools, and declines in measles, mumps and rubella vaccination among our kindergarten students, and the undermining of vaccine policy,” Moss said. “So it’s not going to be a trivial task for the United States to regain its measles elimination status.”
