Pertussis in Adults: Epidemiology and Clinical Implications

Epidemiologic Data from Surveillance and Prospective Studies

Prospective population-based studies estimate the annual incidence of symptomatic pertussis in adults aged 19-64 years ranges from 229-409 per 100,000 population, translating to approximately 299,000 to 626,000 cases annually in the United States 1
The Centers for Disease Control and Prevention (CDC) recommends that prospective data reveal national passive surveillance captures only 1-2% of actual adult pertussis cases 1
Among adults presenting with acute cough lasting ≥5 days who seek medical care, 8-26% have serologically confirmed B. pertussis infection 1
The Canadian Medical Association found that among adults meeting criteria for postinfectious cough, 19.9% had confirmed pertussis 2, 3

The CDC found that in households with a pertussis index case, the attack rate among adult contacts is 21% when a child or adult was the source 1
Adults are frequently the source of pertussis transmission to infants, accounting for 24% of identified sources when parents or grandparents had cough illness 4
In community outbreaks, 23-42% of cases occur among adults aged >20 years 1

The American College of Physicians recommends that adults with pertussis make multiple medical visits: 31% had one visit, 31% had two visits, and 35% had three or more visits during their illness 5, 6
The CDC found that 78% of employed adults with pertussis miss work for a mean of 9.8 days, with 10-16% unable to work for more than 1 month 5, 7, 6
Pertussis is often not considered in the differential diagnosis of chronic cough by many practitioners, contributing to substantial underdiagnosis, according to the American Thoracic Society 2
Many adults present with only a nondistinct protracted cough as the sole manifestation 3

Waning immunity is universal: immunity from childhood vaccination or natural infection wanes within 5-20 years, making all adults susceptible to reinfection, as stated by the Infectious Diseases Society of America 2
Adults serve as the primary reservoir for transmission to vulnerable infants, who account for 92% of pertussis deaths, according to the CDC 4
Complications occur in adults more frequently than commonly perceived, including pneumonia (up to 5%), rib fractures (up to 4%), and hospitalization (up to 3%, or 12% in older adults) 5, 7