HARRISBURG - Gov. Tom Wolf on Monday ordered residents of Pennsylvania’s hardest-hit areas to stay home for at least two weeks to help combat the spread of the new coronavirus that has already sickened hundreds and caused six deaths statewide.

He also shuttered all schools statewide for an additional two weeks.

Noting that Philadelphia has already ordered residents to remain home, Wolf issued his own stay-at-home order for the counties around the city; for Allegheny County, which includes Pittsburgh; and for Monroe County in the Pocono Mountains.

Together, those counties account for 75% of the state’s confirmed cases of COVID-19.

Wolf said the administration wanted to take a “measured approach” to the crisis and expressed hope that if the coronavirus could be largely contained to the most heavily impacted counties, he could avoid extending his stay-at-home order to the entire state.

The order was to take effect at 8 p.m. Monday.

In all, 5.5 million people, or more than 40% of the state’s population, have been ordered to stay home. Wolf said residents will be able to leave their homes for “allowable activities,” including trips to the grocery store and the pharmacy. He did not say how it would be enforced.

Wolf has imposed a series of progressively tougher measures in the face of a global pandemic that state officials say threatens to swamp hospitals and spike the death toll. The governor has already closed schools and ordered all “non-life-sustaining” businesses to shutter their physical locations, an edict that state police and other government agencies began enforcing Monday morning after Wolf beat back a pair of legal challenges.

“The novel coronavirus has halted life as we knew it,” Wolf said Monday. “I won’t pretend that things will not get worse before they get better.”