On Wednesday, Pennsylvania health officials reported its fifth measles-related death of 2026, as the state’s outbreak continues to expand in what can be described as the country’s most serious measles resurgence in decades.The latest death involved Lancaster County resident who had tested positive for measles, according to the Pennsylvania Department of Health. The state now has 943 confirmed measles cases across 39 counties, with 40 new infections reported since September 28. At least 176 people have been hospitalised. The latest death is the third reported in Lancaster County, which has remained one of the hardest-hit areas in Pennsylvania. This has raised the measles death toll in the state to 5, all of whom were unvaccinated. Health Officials Are ConcernedMeasles is one of the most contagious infectious diseases. It spreads when an infected person coughs or sneezes, with the virus capable of remaining in the air for up to two hours after the person has left an area.The outbreak is particularly concerning because measles can cause serious complications, including pneumonia, dehydration, brain swelling and, in rare cases, death.Pennsylvania’s news also comes as measles cases continue to increase across the country. The US has recorded 3,659 confirmed measles cases this year, according to CDC data cited by Reuters, making 2026 the country's worst measles outbreak in decades.Also read: Pennsylvania Measles Cases Cross 900 As US Total Climbs To 3,659 People Who Died Were UnvaccinatedAccording to the Pennsylvania health officials, all the five people who died due to measles were unvaccinated. Of the state's 943 confirmed cases, only four people were vaccinated.Three of the deaths were among unvaccinated adults. The other two deaths were among infants who were too young to have received the measles, mumps, rubella (MMR) vaccine. The numbers highlight the role of vaccination in preventing severe disease and controlling transmission. The MMR vaccine, which protects against measles, mumps and rubella, is highly effective. Two doses provide about 97% protection against measles.According to Pennsylvania’s health department, less than 1% of measles cases occurred in people who were fully vaccinated against the virus. A total of 176 people have been hospitalized, while about 31% of cases occurred in people under 18.In response to the outbreak, Pennsylvania administered more than 53,000 MMR doses in September, more than double the number typically given in a month.Also read: Rabies Day Exclusive: ‘We Need To Target The Source’ For A Rabies-Free India By 2030, Says Veterinary Epidemiologist Officials Are Disagreeing Over The Death Toll There is also a dispute over how measles-related deaths should be counted. Pennsylvania has reported five “measles-associated” deaths, using a state definition that includes people with confirmed measles who die within 30 days of developing symptoms, unless another unrelated event caused the death.The CDC, on the other hand, has confirmed two measles-related deaths nationally after changing its approach to rely on mortality data from the National Center for Health Statistics rather than state health department reports. The disagreement has triggered a public dispute between Pennsylvania Governor Josh Shapiro and US Health Secretary Robert F Kennedy Jr. The CDC has said it is working with state epidemiologists to establish a more consistent definition for measles-related deaths.Measles is preventable, but protection depends on maintaining high vaccination coverage across communities. When vaccination rates fall, the virus can spread rapidly, particularly among people who are too young to be vaccinated, have medical reasons or have not completed their recommended doses.