Chester County's measles case count has climbed to 87, a gain of four in one week. Pennsylvania's outbreak has reached 1,136 confirmed infections, the largest in the U.S. since 1991.

The statewide total jumped from 977 cases on Oct. 2 to 1,136 as of Friday, Oct. 9, a 14% increase, according to the Pennsylvania Department of Health. Chester County remains the third most affected county in the state, trailing Lancaster County, the outbreak's epicenter, which has recorded 415 cases. West Chester-area residents live in one of the hardest-hit counties in Pennsylvania.

Six people have died statewide.

The most recent death involved a 39-year-old woman in Franklin County on Oct. 10, Fox 29 reported. The Franklin County Coroner's Office said she had "several underlying conditions, including a past diagnosis of measles with treatment." All five previously reported deaths involved unvaccinated individuals, according to a Reuters report cited by Fox 29.

Nationally, the Centers for Disease Control and Prevention reported 4,080 U.S. measles cases as of Oct. 9. Pennsylvania accounts for more than 25% of infections nationwide.

Oxford school closure

The outbreak prompted the first measles-related school closure in Chester County. Oxford Area High School closed Friday after a student fell ill with the virus, LancasterOnline reported. A letter posted on the district's website said the Chester County Health Department advised the closure until it could verify measles immunity documentation for high school staff. Anyone at the school without proof of immunity was required to quarantine for 21 days.

Exposure warnings on Baltimore Pike

As we reported Monday, Oct. 12, the Chester County Health Department issued exposure warnings for three Baltimore Pike locations on Sunday, Oct. 4. A contagious individual visited:

  • CVS, 870 Baltimore Pike, Kennett Square, between 10:45 a.m. and 3 p.m.
  • CVS, 857 West Baltimore Pike, West Grove, between 12:30 p.m. and 3:30 p.m.
  • Giant, 849 Baltimore Pike, West Grove, between 1 p.m. and 3:45 p.m.

The health department said anyone who was at those locations during those times and is not immune should contact a health care provider. People who are not immune and may have been exposed should wear a mask in indoor public spaces until three weeks after the exposure.

Vaccination push

Jeanne Franklin, Chester County's public health director, told ABC News on Tuesday, Oct. 13, that her department has been sending vaccination teams directly to homes and businesses at residents' request.

"… We average about 10 people per call but have vaccinated as many as 67 in one location," Franklin said in an ABC News report published by the Everett Post. "When at a home, we have vaccinated in kitchens, porches, living rooms, et cetera."

Statewide, the Department of Health has administered more than 5,900 MMR vaccinations at 201 pop-up clinics since the outbreak began in late April, according to LancasterOnline. The two-dose MMR vaccine is 97% effective at preventing measles.

Pennsylvania Department of Health Press Secretary Neil Ruhland said predicting the outbreak's course is difficult. "The quickest way Pennsylvania's measles outbreak will come to an end is by getting as many people vaccinated as possible," Ruhland told LancasterOnline.

Residents who believe they were exposed or develop symptoms of fever, cough, runny nose, red eyes or rash should call a health care provider before visiting any medical facility. More information is available at chesco.org/measles.