Unvaccinated Montco child tests positive for measles

An unvaccinated Montgomery County child has tested positive for measles, county authorities said Thursday.

The child visited three emergency departments and two grocery stores while potentially infectious: Bryn Mawr Hospital and Costco Wholesale at North Wales on July 20, Children’s Hospital of Philadelphia on July 21, Walmart Supercenter in Hatfield on July 22, and Children’s Hospital of Philadelphia Middleman Family Pavilion in King of Prussia on July 23.

Montco authorities are asking people who visited these locations on those days to review their vaccination records. Investigators from the county’s Office of Public Health are conducting contact tracing efforts, and will reach out to people who were potentially exposed.

» READ MORE: One in five Philadelphia newborns is not protected from measles, CHOP-Penn study finds

The measles virus is highly infectious and can pass through direct contact or the air, according to the Centers for Disease Control and Prevention. The illness can be especially dangerous for children under 5, pregnant people, and those with weakened immune systems. Before the advent of measles vaccines, 400 to 500 people died of the virus each year.

In 2000, after decades of vaccination efforts, the U.S. met the World Health Organization’s definition of measles elimination. But local outbreaks still occur. In recent years, the number of measles cases nationwide ranged from 13 in 2020 to 1,274 in 2019.

A measles outbreak in Columbus, Ohio, during the last fall and winter left 85 children sick. Of those, 80 were unvaccinated.

The number of school children who received their routine vaccines has decreased since the start of the pandemic. Experts worry that the decline will make outbreaks such as the recent one in Ohio more common.