The "100-day cough" still kills unvaccinated infants
Pertussis, caused by Bordetella pertussis, starts like a cold then unleashes weeks of coughing fits—sometimes ending in a high whoop. Fits may last one to six weeks, or ten or more. About half of infected infants under one need hospital care, and nearly 0.5% die. Vaccines work, but protection fades within years.
After an average incubation of seven to fourteen days, a catarrhal stage of mild cough and runny nose gives way to paroxysmal coughing for up to three months, then a convalescent fade. Post-cough vomiting or an inspiratory whoop roughly doubles the odds the illness is pertussis. Infants may show little cough and instead stop breathing. Tracheal cytotoxin kills airway cilia; pertussis toxin drives lymphocytosis that can cause pulmonary hypertension—a major infant death pathway. Humans are the only natural host, though zoo primates have caught it from people.
In 2015 an estimated 16.3 million people were infected and 58,700 died—down from 138,000 deaths in 1990. The bacterium was identified in 1906; vaccines arrived in the 1940s and saved an estimated half-million lives in 2002 alone. Multi-component acellular vaccines are about 71–85% effective against illness, stronger against severe strains, yet immunity may last only three to six years after vaccination and seven to twenty after natural infection. Waning shots plus bacterial escape help explain twenty-first-century resurgence even in vaccinated countries.
Immunization still shifts cases toward infants, adolescents, and adults who can seed households. Pregnancy vaccination strongly protects newborns. Antibiotics (macrolides or TMP/SMX) help most if started within three weeks of symptoms—or six weeks for infants and pregnant patients—mainly by cutting spread rather than curing late cough. Over-the-counter cough medicines have not proved useful. First-year U.S. infants face apnea in about 31% of cases, pneumonia in 12%, seizures in 0.6%, and encephalopathy in 0.15%.
Source: Whooping cough
