Whooping cough hits Allegheny County

| Wednesday, June 18, 2014, 11:14 p.m.

At least 50 people in Allegheny County have come down with whooping cough this year, putting the region on pace for one of its worst bouts in a decade with the respiratory disease.

Most of the reported cases involve school-age children, all of whom recovered, according to county health officials. North Allegheny in McCandless was the most recent school district to confirm cases, announcing this month that two high school students contracted the bacterial ailment that doctors call pertussis.

The highly contagious disease causes violent coughing fits and vomiting, and can be especially dangerous for babies.

“It's probably going to be on the high side this year. Usually, we get 50 or less” cases, said Dr. Kristen Mertz, a medical epidemiologist at the Allegheny County Health Department.

Although the department hasn't listed any pertussis-linked deaths this year, the disease is blamed in at least two fatalities in California, where an epidemic led to more than 3,450 cases since January. Reported cases nationwide topped 24,000 last year, about half the tally from 2012 but up from 11,651 in 2003, according to the Centers for Disease Control and Prevention.

The illnesses in 2012 marked one of the largest pertussis epidemics since the 1950s and could foreshadow worse outbreaks, said Dr. Wilbert van Panhuis, an assistant professor of epidemiology at the University of Pittsburgh.

“It was almost as bad as it was before the vaccine was introduced,” said van Panhuis. Early pertussis shots went mainstream starting in the late 1940s.

While measles, mumps and rubella gain momentum because some people refuse vaccinations, he said, the pertussis issue is more complex. A popular pertussis vaccine introduced in the 1990s cut unpleasant side effects, but doctors realized it sometimes doesn't protect people as long as prior formulas did, van Panhuis said.

“You're seeing adults and teenagers getting pertussis because their vaccinations are not working well,” van Panhuis said.

He said that trend, paired with some people's reluctance over vaccinations, might lead to more epidemics until pharmaceutical manufacturers introduce another pertussis vaccine. Preliminary state health data last month suggested as many as 177 confirmed pertussis cases in Pennsylvania since January.

The state recorded 633 cases in 2013, down from 1,934 in 2012. Doctors said cyclical peaks in case volumes typically develop every three to five years.

The CDC is investigating the waning effectiveness of the current pertussis inoculation, given as part of so-called DTap and Tdap vaccines. The agency is reviewing whether the vaccine could be ineffective on a particular pertussis strain, said CDC spokesman Jason McDonald.

The agency's standard vaccination recommendations could change depending on those investigations, though McDonald wasn't sure when they might be complete. Public health agencies still urge people to get the vaccines and booster shots.

Those who are vaccinated tend to endure milder cases of pertussis if they catch the bug, Mertz said.

“The message isn't that the vaccine is no good. It's still good. It's still effective,” she said. “Most kids are not getting the disease.”

Adam Smeltz is a Trib Total Media staff writer. Reach him at 412-380-5676 or asmeltz@tribweb.com.

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