The number of cases could continue to spike because the flu season typically doesn't peak for at least another couple weeks.
The Pennsylvania Department of Health designated flu as now "widespread" throughout the commonwealth. There have been more than 11,000 laboratory-confirmed flu cases in the state since the flu season began in mid-December, with nearly 4,300 of those reported last week alone.
The Health Department's flu-tracking website www.flufreepa.com said "widespread" is the highest category for tracking the virus. That means there have been outbreaks or increases in flu-like or "laboratory-confirmed influenza in at least half the regions of the state with recent laboratory evidence of influenza in the state."
Eighteen of the 22 flu-related deaths statewide were reported in the past week, the health department said in statistics updated Tuesday. The majority were reported among Pennsylvanians older than 65, but two involved "otherwise healthy young individuals" under 50, the state said.