Whooping cough outbreak primarily affects teens

NEW YORK (Reuters Health) - In a 2003-2004 outbreak of whooping cough in Fond du Lac County, Wisconsin, most cases were diagnosed in adolescents, although adults had more severe disease, public health officials report in the Archives of Pediatric and Adolescent Medicine for January.

After the first cases were reported to the Fond du Lac Health Department in late July 2003, the origin of the outbreak of whooping cough, also referred to as pertussis, was traced to a high-school weight room that was used before the school year started.

"Enhanced surveillance for pertussis, contact identification, diagnostic testing, treatment, and antibiotic prophylaxis were initiated in the community," Dr. Jeffrey P. Davis, of the Wisconsin Division of Public Health in Madison, and colleagues report. Individuals who were infected were requested to stay home during the first 5 days of antibiotic treatment.

The first phase of the outbreak peaked during mid-June to mid-August, but between October and early December, the number of cases again rose sharply, with substantial transmission to adults and children in the community.

Overall, 71 percent of infected patients were between 10 and 19 years of age. Fourteen percent of the cases occurred in patients who were 2 months to 9 years of age and 15 percent occurred in adults. The two infants with pertussis required hospitalization. Adults reported a higher frequency of exacerbations and vomiting than did adolescents.

Davis and colleagues note that patients were diagnosed with pertussis at all 20 public schools in the county.

In most cases, vaccination histories were up to date to the standards at that time, 84 percent having received at least five doses. However, it wasn't until 2005 that pertussis booster vaccines were licensed for use in teenagers and adults.

"This labor- and resource-intensive outbreak highlights potential benefits of pertussis booster vaccination among adolescent and adult populations," the authors conclude.

SOURCE: Archives of Pediatric and Adolescent Medicine, January 2008.