First US measles deaths of 2026 reported amid row over MMR vaccine

The United States has reported its first measles-associated deaths of 2026 as the country experiences its highest number of cases in more than three decades, triggering a fresh political row over vaccination and how the fatalities have been classified.

Pennsylvania health officials announced that two residents of Lancaster County had died after contracting measles, describing them as the state’s first measles-associated deaths in 35 years and the first reported in the US this year. Both individuals were initially described by state officials as unvaccinated, although details surrounding the deaths have since become the subject of disagreement between state and federal officials.

The announcement comes during a major resurgence of a disease that was declared eliminated from the US in 2000. More than 2,700 confirmed measles cases had been reported nationally by 20 August, with 94% occurring in people who were unvaccinated or whose vaccination status was unknown. Almost half of cases were among children and young people aged five to 19.

Pennsylvania has become one of the states most heavily affected. The outbreak has spread across dozens of counties and hundreds of cases have now been recorded, with Lancaster County at its centre. The state has also reported substantial numbers of hospital admissions linked to the outbreak.

However, controversy has developed over whether both fatalities should be attributed to measles. Lancaster County Coroner Dr Stephen Diamantoni said one case involved a newborn baby who tested positive for measles after a family member contracted the disease, but said the infant’s death was caused by a ruptured spleen and that measles did not contribute to the death. Pennsylvania health officials have used the broader term “measles-associated deaths”, while questions surrounding the precise circumstances of the second death have also fuelled the dispute.

US Health and Human Services Secretary Robert F. Kennedy Jr has publicly challenged Pennsylvania’s account, referring to the fatalities as “so-called” measles deaths and accusing state officials of failing to provide federal authorities with sufficient information. Kennedy has gone further by suggesting the deaths may have been misrepresented or even fabricated, claims rejected by Pennsylvania Governor Josh Shapiro and state health officials.

The dispute has intensified an already highly politicised debate around childhood vaccination in the US. Kennedy has a long history of questioning vaccine safety and has faced criticism from doctors and public-health organisations over his messaging on immunisation. During the current measles resurgence, however, he has also publicly encouraged people to receive the measles vaccine and reiterated that vaccination can prevent the disease.

Shapiro has accused Kennedy and the Trump administration of contributing to confusion among parents over vaccines. The Pennsylvania governor said misinformation has real-world consequences and argued that families need clear information from doctors and medical professionals when making decisions about their children’s health.

The row follows further controversy after President Donald Trump called for the combined measles, mumps and rubella vaccine to be separated into individual vaccines. Medical organisations have challenged the proposal, pointing to decades of evidence supporting the safety and effectiveness of the combined MMR vaccine. Two recommended doses provide around 97% protection against measles.

Vaccination coverage among American children has meanwhile continued to fall. Federal data for the 2025-26 school year showed MMR coverage among kindergarten children had dropped to 92.4%, while exemptions from at least one school-required vaccine reached a record 4.2%. Around 280,000 kindergarten children attended school without documentation showing they had completed the MMR vaccination series.

Public-health experts generally aim for vaccination coverage of around 95% to prevent sustained measles transmission because the virus is exceptionally contagious. Falling below that level can create pockets of susceptible people in which an imported infection can spread rapidly, particularly when unvaccinated people are concentrated within particular communities.

Measles can cause fever, cough, a characteristic rash and other symptoms, but complications can be considerably more serious. These can include pneumonia and encephalitis, or swelling of the brain, and the disease can be fatal. Serious complications are more likely among young children and other vulnerable groups.

The current resurgence is particularly striking because measles-associated deaths had become extremely rare in the US. Three deaths were confirmed during 2025, including two unvaccinated school-age children in Texas and an unvaccinated adult in New Mexico. Before those fatalities, the US had not recorded a measles death since 2015.

The controversy surrounding the Pennsylvania deaths is likely to continue while officials establish precisely what role measles played in each case. That uncertainty does not change the wider picture facing the US, where thousands of infections have been recorded, vaccination coverage has fallen and the country is experiencing its largest measles resurgence in decades.

For health officials, the concern now extends beyond the argument over how two individual deaths should be recorded. The US eliminated continuous domestic transmission of measles more than 25 years ago, and the scale and persistence of current outbreaks have raised concerns that the country could ultimately lose that elimination status if sustained transmission cannot be brought under control.

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