US Measles Cases Hit 30-Year High of 4,500, Experts Warn Falling Vaccination Rates Fuel Outbreaks
The United States has recorded more than 4,500 measles cases this year, as a resurgence of the highly contagious infection raises concerns about declining vaccination rates and the risk of further outbreaks.
The US Centers for Disease Control and Prevention (CDC) reported 4,588 confirmed cases as of 22 October 2026, more than double the 2,289 recorded throughout 2025. The current total is the highest since 1991, when the country reported 9,643 cases, according to historical CDC data.
The CDC had recorded three measles-associated deaths and 479 hospitalisations as of 22 October 2026.
The figures highlight the continuing threat posed by a disease that was declared eliminated in the US in 2000, meaning there was no continuous domestic transmission for at least 12 months.
Why Are Measles Cases Rising Across the US?
The latest outbreak reflects several factors, including gaps in vaccination coverage, reduced public concern about measles, and growing distrust of public health advice.
In an interview with ABC News in July, Dr William Schaffner, a professor of preventive medicine at Vanderbilt University Medical Center, warned that the country's progress against measles was being eroded. He also pointed to declining confidence in public health institutions and the spread of unverified claims about the disease.
The CDC's latest figures show that 96% of reported cases in 2026 involved people who were unvaccinated or whose vaccination status was unknown. Children and teenagers aged five to 19 accounted for 42% of cases, while adults aged 20 and older represented 41%.
Vaccination coverage has also fallen below the level generally needed to prevent sustained community transmission. During the 2025–2026 school year, 92.4% of US kindergarten pupils had received the measles, mumps and rubella (MMR) vaccine, below the 95% coverage level generally needed to maintain community protection.
How Dangerous Is Measles?
Measles spreads through the air when an infected person breathes, coughs or sneezes. Symptoms typically include a high temperature, runny nose, cough, red and watery eyes, and a rash that usually begins on the face before spreading across the body.
Although some people recover without major complications, measles can cause serious illness, particularly in young children and people with weakened immune systems. Complications include ear infections, diarrhoea, pneumonia and encephalitis, or inflammation of the brain. Severe cases can require hospital treatment and may be fatal.
Dr Paul Offit, director of the Vaccine Education Centre at Children's Hospital of Philadelphia, told ABC News that measles can be underestimated because successful vaccination programmes have made the disease less familiar to many people.
How Can Families Protect Themselves?
The CDC recommends two doses of the MMR vaccine. One dose is approximately 93% effective against measles, while two doses provide around 97% protection.
People who are unsure of their vaccination status should check their records and speak to a healthcare professional about whether they need vaccination. Anyone who develops symptoms after a possible exposure should contact a healthcare provider before attending a clinic, helping reduce the risk of exposing others.
With cases continuing to rise, public health officials face the challenge of containing outbreaks while rebuilding confidence in vaccination. The latest figures underline how quickly measles can regain ground when community protection falls.