Decline in Vaccinations Could Lead to Millions of Measles Cases in U.S. Over 25 Years

New research published Thursday warns that the U.S. could see millions of measles cases over the next 25 years if vaccination rates for the disease decline by just 10 percent. If current vaccination rates are maintained, the model predicts that hundreds of thousands of cases will still occur during the same period, according to a mathematical simulation created by Stanford University researchers.

Stanford physician Nathan Lo, the study's lead author, stressed the risk, saying, "Our country is on a tipping point for measles to once again become a common household disease."

If vaccination rates stay as they are across different states, the model indicates measles could become deeply ingrained in the U.S., leading to widespread outbreaks, hospitalizations, and fatalities. Lo, who specializes in infectious disease transmission, emphasized that under such conditions, measles-related deaths would become routine.

The study uses state-level vaccination data to predict the disease’s future spread, noting that even a small increase in vaccination — like a 5 percent rise in state vaccination rates — could help prevent a significant rise in cases.

However, Lo expressed concern that vaccination rates for children are likely to continue dropping, which would lead to a sharp increase in infections. Hesitancy around the COVID-19 vaccine has caused many parents to question routine childhood vaccinations, and ongoing debates over state vaccination policies, along with public figures like Robert F. Kennedy Jr. pushing for changes to the childhood vaccine schedule, could further reduce immunization rates.

Mujeeb Basit, a professor at UT Southwestern Medical Center, who wasn’t involved in the study, described the findings as a stark warning: “This is a warning of what our future could look like.” He added that reversing the trend of declining vaccination will require substantial time and effort to vaccinate large numbers of people.

As of 2025, the U.S. has already recorded about 800 measles cases, the highest number in a single year since 2019, with cases continuing to rise. Montana recently reported its first measles cases in 35 years, and a major outbreak in West Texas has resulted in the deaths of two children, with a third death in New Mexico linked to the same outbreak.

A recent KFF poll found that many Americans are uncertain about the measles vaccine, with more than half of surveyed adults unsure about the truth behind misinformation, such as the claim that the vaccine is more dangerous than the disease. These falsehoods have been amplified by figures like Kennedy.

Before the measles vaccine was introduced in 1963, the U.S. experienced annual outbreaks, with millions infected and thousands hospitalized or dying. Measles was officially declared “eliminated” in the U.S. in 2000, meaning it no longer spread continuously for over a year, though cases still occur, often due to international travel from under-vaccinated individuals returning from endemic regions.

The modeling also looked at the potential for other diseases to become endemic with declining vaccination rates. For example, a 35 percent drop in rubella vaccinations could lead to the disease becoming endemic, while polio might make a comeback with a 40 percent drop in immunization.

The researchers used state-level vaccination, birth, and death rates to model how measles would spread if immunization rates fell. They estimated that current measles vaccination coverage in the U.S. ranges from 87.7 percent to 95.6 percent, but to prevent outbreaks, 95 percent of the population needs to be vaccinated.

The study predicts how measles could spread across communities and states, and even the most conservative estimates emphasize the severe consequences of a resurgence of the disease in the U.S.