55 Pa. counties have substantial spread of COVID-19, positive test rate rises slightly Updated Apr 20, 2021; Facebook Share Even as the state’s vaccination rollout improves, most of Pennsylvania’s counties are showing substantial spread of COVID-19, Gov. Tom Wolf’s office said Tuesday. Across Pennsylvania, 55 of the state’s 67 counties are showing high transmission of the coronavirus, according to the Wolf administration. Last week, 50 counties showed substantial spread of the coronavirus. The positive test rate for COVID-19 rose to 9.6% for the week of April 9-15, a slight increase from 9.5% the previous week. The positive test rate has now risen for five consecutive weeks, although the rate has only increased by a tenth of a percentage point in each of the past two weeks.