You didn't get your flu shot and here comes the fallout, rolling over you like a freight train: high fever and chills, sore throat, aching joints and muscles, and coughing, coughing, coughing, coughing. At some point, you might even get to visit the emergency room.
Influenza is now widespread throughout Pennsylvania and many other states, and southwest Pennsylvania has seen its number of confirmed cases spike in the past week, with the number of flu cases expected to continue climbing in the weeks ahead, health experts say. But this year's vaccine is a good match for the strains of virus circulating now, they said, and local residents can still get a flu shot that could spare them extreme misery and even possible hospitalization.
"The message for the public is that if you have not received a flu shot, it's not too late," said Marc Itskowitz, an associate professor of medicine and an internal medicine practitioner at Allegheny General Hospital on the North Side. "This is an active season with potentially severe cases, and I would encourage patients to receive a flu shot if they have not yet received one."
Vaccines in past years haven't always been a close match to the viruses causing that year's illness -- viruses tend to change from year to year, and vaccine companies must prepare the next flu season's vaccines several months before anyone knows for sure what is circulating. But this year, it matches well, according to Allegheny County Health Director Karen Hacker.
"This year, it's quite good," said Dr. Hacker, who also advised frequent hand-washing, sneezing and coughing into one's elbow and staying home if ill to prevent spreading viruses. "It's very protective."
But don't dally if you still need a flu shot, health experts said.
After vaccination, the body takes approximately 14 days to build a full immune response to the flu, but health officials said the flu season has not peaked -- and that even after the typical peak in late January or February, flu circulates widely as late as April so it's still worthwhile to immunize. And even if someone has already had the flu, they are still subject to contracting several other strains against which a flu shot would protect them.
In Allegheny County, the number of flu cases has been on the upswing since mid-December, according to state and county health officials. In data filed Thursday, the department reported 44 lab-confirmed cases of influenza since September -- with 26 of those cases confirmed in the week ending Dec. 28, according to Dr. Hacker. While the number of confirmed cases is relatively small, few cases of "influenza-like illness" of fever over 100 degrees along with cough, sore throat or both that are reported by emergency rooms are actually sent to a lab for testing; for each confirmed case, there's likely another 100 unconfirmed cases in the community, Dr. Itskowitz said.
In Allegheny County, 159 cases of confirmed and suspected flu were reported as of Dec. 28, including one flu-related death of a 62-year-old woman, according to Dr. Hacker. In addition, the state reported 121 cases in Butler County, 89 cases in Westmoreland, 74 cases in Beaver, 66 cases in Washington County, 63 in Fayette County and 9 each in Greene and Armstrong counties during that period.
Based on projections from the U.S. Centers for Disease Control and Prevention, the state health department estimates that as many as 1.2 million Pennsylvanians get the flu each year, with as many as 2,000 dying from flu complications. Nationally, 25 states including Pennsylvania are reporting widespread incidence of flu, with 1,711 confirmed cases and six pediatric deaths. Last year, 171 children died of flu complications nationally, according to the CDC.
The strain of flu that is causing most of the illness is a version of H1N1 that re-emerged in 2009 for the first time since the late 1960s and predominantly affected older teenagers and young adults in their 20s and 30s who didn't have the prior exposure their parents and grandparents had had decades earlier. That group appears to be suffering again this year, Dr. Itskowitz said.
"Unfortunately, we've seen some very severe cases, mostly in very young patients who have not been vaccinated and who in some cases have experienced respiratory failure or pneumonia," he said.
People who have begun to recover from the flu should be alert for a return of their high fever after a few days, said Marian Michaels, a pediatric infectious disease specialist at the University of Pittsburgh and Children's Hospital of Pittsburgh of UPMC. Most cases of hospitalization or death from the flu are a result not of the virus but of the bacterial pneumonia that sometimes exploits the patient's weakened immune system.
"When they get a new high fever, and respiratory distress where they're having trouble breathing, that's when we worry about secondary bacterial infection and we recommend they call their doctors," Dr. Michaels said.
Such serious complications are another reason to get the flu shot, especially for family members of infants younger than 6 months old and still too young to receive the flu vaccine, she said. She said several young infants have been admitted to Children's and have tested positive for influenza, which means someone in their family or day care center had the flu and gave it to them.
Immunizing everyone who comes in contact with a young infant -- known as "cocooning" -- is essential, she said.