US measles cases hit 35-year high as vaccination rates plummet

By mid-July, the United States had documented 2,318 measles infections in 2026—a threshold not crossed since 1989, when the country was in the grip of a three-year epidemic that sickened more than 55,000 people and killed 123. What makes this year's surge particularly unsettling is that we are only halfway through it. The virus continues to spread across the country, state by state, outbreak by outbreak, in a pattern that epidemiologists describe as avoidable.

The burden falls heaviest on the young. Nearly seven in ten of those infected are children and teenagers under nineteen. Infants and toddlers under five make up a fifth of all cases, and one in ten of them have required hospitalization. Among older children and adolescents, the hospitalization rate is lower but still significant—three percent of those aged five to nineteen who caught measles ended up in a hospital bed. So far this year, measles has sent 151 people to the hospital. No deaths have been recorded since January, though the disease remains capable of killing in severe cases.

The arithmetic of the crisis is straightforward. Measles is preventable. The MMR vaccine—a single shot that protects against measles, mumps, and rubella—is 97 percent effective after two doses. Yet vaccination coverage among kindergarten children has slipped to 92.5 percent, below the 95 percent threshold that public health officials say is necessary to maintain herd immunity, the protective barrier that keeps the virus from spreading through a population. This decline began during the Covid-19 pandemic and has not reversed. The virus has exploited the gap.

Where the virus has taken hold, it has done so with force. Forty-five states and the District of Columbia have reported cases. Thirty-five distinct outbreaks have been identified, nearly double the number from 2025. One outbreak, which began in South Carolina in October 2025, infected nearly a thousand people over six months—the largest single-location measles outbreak in the United States since the disease was officially declared eliminated in 2000. South Carolina, Utah, Arizona, Texas, Florida, Virginia, and Pennsylvania have borne the heaviest caseloads. Only sixteen cases have been traced to visitors from abroad; the rest are homegrown.

Ninety-three percent of those infected this year were unvaccinated. The remainder had received one or two doses before falling ill. The pattern is consistent with what happens when vaccination rates drop below the threshold needed to stop transmission. The virus finds the unprotected and moves through them.

Health officials have pointed to a specific source of the erosion in public confidence: the anti-vaccine positions embraced by Robert F. Kennedy Jr., now the U.S. Health Secretary. Kennedy has repeatedly promoted the claim that measles vaccines cause autism, a theory contradicted by overwhelming scientific evidence. Federal health leaders, officials say, have dismissed measles as a minor threat and spread misleading information about the MMR vaccine. Andrew Racine, president of the American Academy of Pediatrics, described the situation plainly: "Halfway into 2026, the US is experiencing the worst year for measles since 1991. We are witnessing an avoidable crisis that disproportionately hurts children."

The elimination status that the United States achieved in 2000—a declaration that measles transmission had been stopped—is now under review. The Pan American Health Organization has delayed its decision on whether that status should be revoked until November. The question is no longer whether measles has returned to America. It has. The question now is whether the country can reverse course before the year ends.