Pertussis more common among older adults than previously thought, GSK study finds

NEW YORK — While pertussis is often considered a childhood disease, a new study from GlaxoSmithKline indicates it's a lot more common among older adults than commonly reported.

The study, released Thursday at the 2013 Interscience Conference on Antimicrobial Agents and Chemotherapy, estimated that the actual number of pertussis cases among adults ages 50 years to 64 years was about 520,000 this year, as opposed to the 8,764 cases that were treated, and about 465,000 among those ages 65 years and older, despite the 6,359 cases treated.

In other words, that means about 202 cases per 100,000 adults ages 50 years to 64 years, and 257 per 100,000 among those ages 65 years and older — about 42 to 105 times higher than those that are medically attended.

"The [Centers for Disease Control and Prevention], other public health authorities and infectious disease experts have long suspected that pertussis cases in adults go undetected or are misdiagnosed as other respiratory ailments," GSK Vaccines VP and director of scientific affairs and public health Leonard Friedland said. "To our knowledge, this is the first attempt to quantify the incidence of cough illness attributed to B. pertussis via regression modeling among those greater than 50 years old."