H1N1 influenza cases in Allegheny County continue to rise, prompting the county Health Department to conclude that the flu has yet to reach its peak.

In an effort to counter the epidemic, the U.S. Centers for Disease Control and Prevention has allocated 566,000 doses of H1N1, or swine flu, vaccine to Pennsylvania.

The vaccine has been distributed to 570 certified providers statewide, including pediatricians, family health practitioners, obstetricians, hospitals, schools, colleges and universities that agreed to target the priority groups as identified by the Advisory Committee on Immunization Practices.

Priority groups include individuals 6 months to 24 years old, household contacts and caregivers for children younger than 6 months old, pregnant women, health care providers and emergency services personnel, and those under 65 with underlying health conditions.

Because of vaccine production delays, Pennsylvania likely won't receive as much vaccine by the end of October as was reported earlier. The CDC continues allocating vaccine as it is released by manufacturers, with anticipation that there eventually will be enough for everyone who wants to receive it, including people outside the priority groups.

People are advised to contact their health care provider for the vaccine. If none is available through a provider, call 877-PA HEALTH or visit www.H1N1inPA.com.

In last week's county survey of eight local emergency rooms, more than 10 percent of all emergency patients complained of flu-like illness. This week, the percentage climbed above 13, county health department spokesman Guillermo Cole said.

Six percent of all emergency-room cases last spring involved H1N1, with the county recording about 2 percent in early August.

Since early September, the numbers have climbed dramatically, indicating that the worldwide H1N1 pandemic has hit the region with full impact.

While health officials originally suspected that H1N1 would run its course in eight to 12 weeks, the rising number of cases after six or seven weeks suggests it might be more persistent than expected.

"It's continuing to climb, and that clearly has been the trend since the beginning of September," Mr. Cole said. "We can't say that it has peaked yet with the prevalence of flu-like illnesses. When the number levels off, it may represent a peak and begin to fall. But there is no indication of that yet."

Through its H1N1 surveillance program, the county health department has begun documenting the number of hospitalizations of patients with the flu. No data are yet available.

"The majority of people are young adults and children, and that's continuing," Mr. Cole said. "Seventy percent, or close to three quarters of all cases, involved people under 25 years of age."

One person has died from H1N1 in Allegheny County, with another death in Butler County. No deaths were reported in the region this week.

In another concern, the seasonal flu season is expected to begin in coming weeks. For now, Mr. Cole said, Allegheny County has yet to document its first case of seasonal flu.

Looking for more from the Post-Gazette? Join PG+, our members-only web site. You'll get exclusive sports content, opinion, financial information, discounts from retailers and restaurants, and more. Our introduction to PG+ gives you all the details.