The Pennsylvania Department of Health announced on Friday that 55 new cases of measles have been reported since Wednesday. Since the start of the year, a total of 890 cases have been confirmed in the state, with the outbreak leading to 173 hospitalisations and four deaths linked to measles.
Less than 1 per cent of the reported cases involve individuals vaccinated against measles, while 31 per cent of those affected are under the age of 18. The highest number of cases in the state has been recorded in Lancaster County, where 359 cases have been confirmed. The department states that it is working proactively with residents, community organisations and health professionals to combat the outbreak, through access to fact-based information and the MMR (measles, mumps and rubella) vaccine.
Since the outbreak began in late April, more than 5,300 doses of the MMR vaccine have been administered at 150 temporary clinics in affected communities. Dozens of additional clinics are planned for the coming weeks and months, and state health officials have administered more than 7,900 doses of the MMR vaccine to residents this year. Health officials in the state are noting an increase in public interest in vaccination.
The department stresses that the best protection against measles remains full vaccination. The MMR vaccine boosts the immune system and provides 97 per cent protection over a lifetime, with two doses providing the best protection. Mortality from measles occurs in one to three patients per 1,000 cases.
Measles was declared eliminated in the United States in 2000. The disease spreads through coughing and sneezing, and the virus can remain in the air for up to two hours after an infected person has left the area. Symptoms typically begin seven to 14 days after infection, and may include high fever, cough, runny nose and red, watery eyes, followed by a rash that spreads down the body.
The federal administration has also come under scrutiny. Robert F. Kennedy Jr, the health secretary, stated on social media that the deaths linked to measles in Pennsylvania may have been fabricated for political reasons. In August, the director of the Centers for Disease Control and Prevention (CDC) instructed agency staff not to include two measles-related deaths reported by Pennsylvania in the national records, with the CDC stating that it was reviewing additional information on those deaths.
According to data as of 24 September, more than 3,659 confirmed cases of measles have been reported in the United States this year. Throughout 2025, a total of 2,289 confirmed cases have been recorded in the country.
