Four fully vaccinated Pennsylvanians, including a Lancaster County resident, contract measles
Four people in Pennsylvania who had received two doses of the MMR vaccine have tested positive for measles, marking the first such cases in the statewide outbreak that has affected hundreds.
State health officials said four Pennsylvania residents who were fully vaccinated with two doses of the measles-mumps-rubella (MMR) vaccine have now been diagnosed with measles. The cases include three adults and one child from Lancaster, Centre, Jefferson and Lycoming counties; none required hospitalization.
The patients are the first fully vaccinated individuals to fall ill in the current outbreak, which has infected 676 people statewide, including 295 in Lancaster County. Health officials noted a recent surge of 49 new cases in Lancaster County over a seven-day period.
"While vaccinated individuals contracting measles is unusual, as community transmission rises and our overall case numbers increase, we see a handful of people who were vaccinated will get measles," said Pennsylvania Secretary of Health Dr. Debra Bogen during a virtual briefing.
The Centers for Disease Control and Prevention estimates that two doses of the MMR vaccine are about 97% effective, meaning roughly three out of 100 fully vaccinated people could still become infected after exposure.
Dr. Pia Fenimore, chief and vice chair of pediatrics at Penn Medicine Lancaster General Health, said that if a fully vaccinated person does contract measles, the illness is typically milder and less likely to cause serious complications. She advised individuals uncertain about their vaccination status to consult their healthcare provider and consider antibody-titer testing.
Pennsylvania previously reported two infant deaths linked to measles in August. One infant, Ivan Miller, died from a ruptured spleen despite testing positive for measles; the second infant, Mary Stoltzfus, had a pre-existing condition and died after testing positive, though officials have not confirmed the cause.
The outbreak adds Pennsylvania to a growing list of states experiencing a resurgence of measles, a disease once declared eliminated in the United States. As of early September, South Carolina reported the highest national case count, but Pennsylvania's recent increase may soon surpass it.