More than half of the flu cases reported in Pennsylvania so far this season are in the Greater Pittsburgh area, with Allegheny County having the most of any county in the state in a season that is off to an early start.
A total of 4,424 laboratory-confirmed cases of influenza have been reported, with reports from 64 of the state’s 67 counties, according to data released Tuesday by the state Department of Health.
Flu activity is widespread and increasing in all regions of the state.
Seven counties in Greater Pittsburgh area — Allegheny, Armstrong, Beaver, Butler, Fayette, Washington and Westmoreland — account for 2,330 of the cases, or 53%.
Overall, Allegheny County leads the state with 28% of all flu cases. The county totaled 1,223 for the week ending
Dec. 7 — spiking from 665 cases reported the week ending Nov. 30.
“We really don’t know or have a reason as to why” Allegheny County has so many flu cases, said Brittany Lauffer, state health department spokeswoman. “It could be that someone who was sick was at a heavily populated area and exposed other people. It could be due to outbreaks within health care facilities.”
The higher number could be due to doctors testing more patients for flu, said Dr. Joe Suyama, chief of emergency services at UPMC
The flu season generally begins in October. The number of cases is higher at this time of year than in prior years, said Dr. Amesh Adalja, an infectious disease specialist based in Pittsburgh.
“Some models are saying there’s a 40% chance that the season will peak in December when the traditional peak is in February,” said Adalja, who is a a senior scholar at the Johns Hopkins Center for Health Security.
In Pennsylvania, flu cases typically don’t start to increase until mid-December or later, Lauffer said. This year, isolated cases were seen as early as October, picking up speed in November.
“Our case counts for November, and so far in December, are higher than what they normally are for this time of year,” she said.
But it’s too soon to know how severe it will be.
“It’s very early in the flu season and there are a lot of unknowns, so it’s difficult to make any predictions or speculate,” said Dr. Kristen Mertz, an epidemiologist with the Allegheny County Health Department.
Three types of influenza are circulating, with Type B being dominant, accounting for 74% of the state’s confirmed cases.
“We have seen a larger number of flu cases this year compared to last year at this time, particularly Type B flu,” Mertz said. “Nationally at this time, type B is the most common type affecting children, and we’ve seen similar trends in Allegheny County. Overall, 58% of our reported flu cases are among those less than 20 years or age. Despite the recent increase in overall cases, the number of reported flu hospitalizations is relatively low, with 11 reported to date.”
There have been 100 flu-related hospitalizations and six deaths reported to-date this season, according to the state health department. Five of the six were age 65 and older, with one in the 50-64 age group.
The state does not disclose where deaths occur to protect patient privacy, Lauffer said.
No deaths have been reported in Allegheny County, according to the county health department.
UPMC and Allegheny Health Network facilities are seeing the early start to the flu season with more activity, according to UPMC’s Suyama and Dr. Marc Itskowitz, a primary care physician with AHN.
The season started mostly in the south, Adalja said.
The highest levels of influenza-like illness were reported in Texas, Louisiana, Mississippi, Tennessee, Alabama, Georgia, and South Carolina, as well as Nebraska and Puerto Rico, according to Nov. 30 data from the U.S. Centers for Disease Control and Prevention. The activity in Pennsylvania was still classified as low.
Although three strains are present, Type B is dominating, which Adalja said is usually seen later in the season.
The early start stresses the need for people to be vaccinated, Adalja said.
It’s not yet known how effective the vaccine is. The CDC will release a preliminary analysis in January, Itskowitz said.
“We do have the strains within the vaccine, so there should be some level of protection,” he said, cautioning that could change if the strains mutate.
Adalja said there have been about a half dozen pediatric deaths from the flu, which he said should reinforce that influenza “is a disease that will routinely kill every year.”
“People sometimes forget and think of it as a mild illness,” he said. “It is something you have to think about as well.”
The flu causes a spectrum of illnesses, and people can have mild or severe symptoms, or none at all, with how sick they become depending on their individual genetics, Adalja said.
Flu can continue to spread until May, and it’s not too late to get a flu shot.
Brian C. Rittmeyer is a Tribune-Review staff writer. You can contact Brian at 724-226-4701, [email protected] or via Twitter .