Pertussis [whooping cough] cases rising in teens; booster advised

By Joyce Howard Price
THE WASHINGTON TIMES
March 27, 2006

Cases of pertussis, or whooping cough, are rising among U.S. adolescents and young adults, so teens should consider booster shots, given their risk of infection in school outbreaks, a federal report says.
    Although the highly contagious coughing illness is still most harmful to infants, the report shows that during 2004, the greatest number of reported pertussis cases were among youths (ages 11 to 18), followed by adults (19 or older).
    Of the more than 25,800 pertussis cases reported that year, nearly 8,900 were in adolescents and pre-adolescents, while nearly 7,500 were among those 19 or older.
    "Pertussis ... remains endemic in the United States, despite routine childhood pertussis vaccination for more than half a century and high coverage levels in children for more than a decade," said authors of the report published Friday in the Centers for Disease Control and Prevention's (CDC) Morbidity and Mortality Weekly Report.
    "A primary reason for the continued circulation" of the infection, the report said, "is that immunity to pertussis wanes approximately 5 to 10 years after completion of childhood pertussis vaccination, leaving adolescents and adults susceptible."
    In a statement, the authors, who include investigators in the CDC's National Immunization Program and other federal medical and vaccine programs, said: "Among the diseases in which universal childhood vaccination has been recommended, pertussis is the least well-controlled reportable bacterial, vaccine-preventable disease in the United States."
    It is rare for pertussis to kill a teen or adult, but those infected can spread the germ to vulnerable babies with whom they have contact. But even in older victims, the symptoms -- including "spasmodic cough ... vomiting, and inspiratory whoop" or a crowing intake of breath -- "can last months," the researchers said.
    For example, they noted that Massachusetts surveillance data showed that 38 percent of adolescents in the state who reported pertussis between 1989 and 2004 "had already been coughing for more than a month at the time they were diagnosed." A study in Quebec indicated 97 percent of adolescents with pertussis coughed for more than three weeks, and 47 percent coughed for more than nine weeks.
    The authors say the average number of annual U.S. pertussis cases and deaths were enormous before the introduction of childhood vaccination in the 1940s: 200,752 cases and 4,034 fatalities, respectively. The number of cases "declined dramatically" with the advent of a vaccine, they said, reaching a historic low of 1,010 in 1976.
    "But since the 1980s, the number of reported pertussis cases has been steadily increasing, especially among adolescents and adults," the federal scientists said.
    In addition to the fact that many who were vaccinated as children are experiencing reduced immunity, the authors say, there may also be a "true increase in the burden of disease and an increase in the detection and reporting of cases."
    "During 2000 to 2004, a total of 11 states had an annual incidence of reported pertussis in adolescents of 50 or more cases per 100,000 population during at least one year," investigators said. Incidence in the rest of the nation averaged 7.3 cases per 100,000 population.
    Citing serious pertussis outbreaks in middle schools and high schools in states including Wisconsin, Arkansas, Vermont and Massachusetts in recent years and noting that 62 percent of the Massachusetts cases involved patients younger than 16, this "suggests that pertussis booster vaccinations early in adolescence could have a substantial impact on the burden of pertussis in adolescence," the authors concluded.