In a story recently published by The Conversation U.S., Associate Professor of Biology Becky Dawson explains how western Pennsylvanians can stay safe with measles infections once again on the rise.
The Pennsylvania Department of Health has confirmed 693 measles cases across 38 of the state’s 67 counties this year, as of Monday, Sept. 14. In Allegheny County, Dawson continues, the kindergarten MMR vaccination rate has dipped below the required threshold to prevent the infection’s spreading.
“Measles was eliminated in the United States through vaccination in 2000, meaning person-to-person spread of the disease was disrupted,” she writes. “However, due to declining vaccination rates, measles is once again spreading throughout Pennsylvania, resulting in approximately four times as many measles cases in 2026 within the state as in the previous 30 years combined.”
Dawson adds that people who have previously been vaccinated — or previously contracted the virus — have only about a 3% chance of developing measles if exposed. That’s compared to an approximately 90% chance of infection after exposure for unvaccinated adults and infants alike.
