Read condition-specific symptoms and clinical context for Bordetella pertussis. The whooping cough bacterium: a cold-like start that can turn into weeks of coughing fits.
B. pertussis causes whooping cough, a respiratory illness that CDC describes as beginning like a common cold before the coughing can last for weeks or months. The bacteria attach to the hair-like structures lining the airways and release toxins that damage them. Illness is often milder in people who have been vaccinated, and PHAC cites a high prevalence of asymptomatic infection among household contacts. Many babies do not cough at all and instead have life-threatening pauses in breathing. WHO notes epidemics every two to five years.
CDC states it usually takes 5 to 10 days for symptoms to appear after exposure, and sometimes as long as 3 weeks. These early symptoms resemble a common cold and can last 1 to 2 weeks.
Possible symptoms: Runny or stuffed-up nose; Low-grade fever; Mild, occasional cough; Apnea in babies.
Apnea or breathing pauses in a baby need emergency care. CDC’s Pink Book gives the incubation period as commonly 7 through 10 days with a range of 4 through 21 days, slightly different from the public-facing 5 to 10 days; both are recorded here rather than merged.
After 1 to 2 weeks, CDC describes violent coughing fits that can last 1 to 6 weeks and up to 10 weeks, with people usually seeming well in between.
Possible symptoms: Violent coughing fits; High-pitched whoop when inhaling after a fit; Vomiting during or after coughing fits; Very tired after a coughing fit.
CDC states that people with whooping cough are contagious for at least 2 weeks after coughing begins, and that providers diagnose it from the history of typical signs and symptoms, physical examination, laboratory mucus samples and blood tests.
Infection can be mild or silent, particularly in previously vaccinated older children and adults.
CDC’s Pink Book states that previously vaccinated older people may be asymptomatic or have illness ranging from a mild cough to classic pertussis, and that they often serve as the source of infection for infants. PHAC cites a high prevalence of asymptomatic infection among household-exposed people. None of the staged symptoms listed above apply to this state.
CDC states that experts believe much of this disease goes unrecognized and unreported. Clinical context and laboratory testing distinguish infection from illness.
Source check: 2026-09-19. Educational content; independent scientific review remains pending.