PITTSBURGH (KDKA) – Allegheny County is experiencing a high number of whooping cough cases with 51 confirmed and probable cases reported so far this year compared to about 47 cases reported in all of 2013.
The most recent school district to report cases was North Allegheny, where two high school students contracted the disease.
Earlier this year, Taylor Allderdice High School had a dozen cases.
Whooping cough is a bacterial infection, spread through the air. Cases tend to peak every three to five years.
Some cases could be related to what's called waning immunity, that is, the vaccine's effects wear off.
For people who catch the illness, spread can be curbed with antibiotics.
"We're certainly expecting that we'll have more before the end of the year," said Dr. Karen Hacker, director of the Allegheny County Health Department. "But I can't tell you this is going to be a dramatically different year than last year."
One issue is the newer vaccines. They have less side effects, such as arm soreness and redness, but they don't protect as long. A booster shot given in early adolescence may wear off by late adolescence.
"Whooping cough is definitely very contagious," Hacker explained, "and so when you have a cluster of cases, particularly in schools, that's the age group that tends to get it, and they tend to infect one another."
The infection causes fits of severe coughing in children, teens and adults. But the big worry is for babies.
"Infants who are less than 1-year-old tend to have more severe cases," said Dr. Kristen Mertz, an epidemiologist at the Allegheny County Health Department. "We get more hospitalizations and even deaths occasionally."
The spread can be limited by treating infected people with the appropriate antibiotics.
While vaccines aren't perfect, they still work well. Most children who are vaccinated do not get whooping cough.
Nationwide, 2012 was an especially bad year for whooping cough -- one of the largest epidemics since the 1950s. Last year, Pennsylvania had more than 600 cases, compared to nearly 2000 in 2012.
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