Dec. 15--But the 17-year-old North Philadelphia youth did vomit, almost continuously, for three weeks last March. He dropped 10 pounds and stopped attending classes at George Washington Carver High School of Engineering and Science. Playing basketball became impossible.
Doctors prescribed antibiotics, but nothing seemed to work. Collick grew weaker and dehydrated. Finally, his mother, Pearl Fletcher, took Collick to Children's Hospital of Philadelphia, where the 6-foot-1 athlete was diagnosed with whooping cough, a disease normally associated with infants and toddlers.
"By that time, I was frantic," Fletcher said. "It was scary. With a child that big, whooping cough is one of the last things you would think of."
But adolescents and adults are contracting whooping cough at rates that have pushed the incidence of the disease, which tends to spike in three-year cycles, to its highest point since 1964. Nationally, 9,771 cases of whooping cough, or pertussis, were recorded last year, according to the federal Centers for Disease Control and Prevention in Atlanta.
The increases are coming because doctors are discovering that whooping cough -- so named for the barking-seal sound that a sickened child often makes -- occurs more frequently with adolescents and adults than previously thought. Public health officials also believe the current spike is being heightened by lower immunization rates during the 1980s.
Several outbreaks have happened locally. In 12 years in the Cheltenham Township School District, Cedarbrook Middle School principal Iris Parker had never seen a student suffering from whooping cough -- until this year.
She sent seven students home this year, after an outbreak was diagnosed in the school system. Three students eventually tested positive, among the 33 probable and confirmed cases of whooping cough recorded in Montgomery County this year, double the number of last year.
In Philadelphia, the number has also nearly doubled, from 33 to 64. Since whooping cough is highly contagious -- 95 percent of those exposed to the bacteria through coughing or sneezing get the disease -- people may become infected with pertussis and not know it, said Barbara Watson, medical director of the Immunization Program for Disease Control with the Philadelphia Health Department.
A survey conducted by the city and the CDC in 1993, when Philadelphia experienced a record 120 cases, showed that for every reported pertussis case, 40 other people were probably infected, Watson said.
Once diagnosed, whooping cough is treated with medication that reduces transmission of the bacteria. The cough itself can linger even after treatment, which has caused the disease to be labeled the "100-day cough." Even people who have been exposed to whooping cough should take medication to avoid passing it to others, Watson said.
Many sufferers don't seek medical attention because the disease resembles a cold at first, with runny nose, low-grade fever, and a mild, occasional cough.
Eventually, the coughing attacks become more severe and frequent, happening an average of 15 times a day. The trademark "whoop" comes as a patient attempts to draw a breath at the end of an attack.
Because teenagers and adults often don't "whoop," they may believe they simply have the flu, said Alice Gray, director of immunizations for the Pennsylvania Department of Health. And that's when the disease spreads to those most vulnerable: infants.
Children under 12 months remain the most chronic sufferers of pertussis, and the number of reported cases among them increased 49 percent in the 1990s, according to an article published last week in the Journal of the American Medical Association.
In Philadelphia, 60 percent of the cases this year are in babies under 4 months old, Watson said. Most catch the disease from young mothers, who grew up in the 1980s when immunization rates were in the 30 percent range, she said.
The vaccine for pertussis has been around since the late 1940s. It was responsible for drastically reducing the disease, which caused 7,518 deaths in 1934. So far in 2003, there have been 13 deaths, 10 occurring in children under 3 months.
The current national immunization rates for pertussis -- the "P" in the standard DTaP vaccination -- are high, nearly 90 percent, according to Greg Wallace, an epidemiologist with the National Immunization Health Program at the CDC. The shots are given at 2 months, 4 months, 6 months, between 15 and 18 months, and between 4 and 6 years.
Philadelphia's immunization rate is lower, 72 percent, Watson said. Often babies will receive just one or two doses, when at least four are needed to protect them, she said.
Even if a child receives the required pertussis shots, the effectiveness of the vaccine wears off over time, which is why adolescents become more susceptible. Of the 33 confirmed and suspected cases in Montgomery County this year, 16 were adolescents.
Experts believe a whooping cough vaccination for adults and adolescents could stop the increase. Such a vaccine is in use in Australia, Germany, and other European countries, and two drug companies -- Aventis Pasteur and GlaxoSmithKline -- have patents for such a vaccine pending before the Food and Drug Administration, Watson said.
Even with a vaccine for older children and adults, whooping cough is unlikely to ever be vanquished, experts say, as the bacteria are unusually hardy, and it takes only one infected person to start spreading it.
"We have basically eliminated polio in the United States," the CDC's Wallace said. "I don't expect that to happen with pertussis."
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(c) 2003, The Philadelphia Inquirer. Distributed by Knight Ridder/Tribune Business News.