Pertussis
Pertussis, also called whooping cough, is a highly contagious bacterial respiratory infection that can cause severe coughing fits and is most dangerous for babies.
What pertussis is
Pertussis is a vaccine-preventable respiratory disease caused by Bordetella pertussis. It can affect people of any age, but babies are the group most likely to need hospital care. The illness often begins like a cold, then shifts into weeks of intense coughing fits that can disrupt breathing, feeding, and sleep.
How it spreads
Pertussis spreads through respiratory droplets when an infected person coughs, sneezes, or spends close time with others. It is especially contagious in households, schools, childcare settings, and other close-contact spaces. People can spread pertussis before they realize the cough is more than an ordinary cold.
Symptoms
Early symptoms can include runny nose, mild cough, low fever, and pauses in breathing in infants. After one to two weeks, coughing fits can become severe. Fits may end with a whoop, vomiting, exhaustion, or trouble catching breath. Vaccinated people can still get pertussis, but illness is often milder.
Why infants are vulnerable
Young babies may not cough with the classic whoop. Instead, they may stop breathing, turn blue, struggle to feed, or become very tired. Complications can include pneumonia, seizures, brain injury from low oxygen, dehydration, weight loss, or death. Protecting infants depends on vaccination during pregnancy, vaccination of close contacts, and quick treatment after exposure or illness.
Diagnosis
Clinicians diagnose pertussis using symptoms, exposure history, vaccination history, local outbreak information, and laboratory tests. Nasopharyngeal swabs can be used for PCR or culture, especially early in illness. Timing matters because testing becomes less useful after weeks of coughing or after antibiotics have been started.
Treatment
Antibiotics can reduce spread and may lessen illness if started early, before severe coughing fits are established. Later treatment may not stop the cough quickly because airway irritation can persist. Infants, pregnant people near delivery, and people at high risk often need urgent evaluation after exposure.
Vaccination
Pertussis vaccines are given in combination with diphtheria and tetanus vaccines. Children receive DTaP, while older children, adolescents, adults, and pregnant people receive Tdap according to schedule and risk. Vaccination helps prevent severe disease, but protection can fade over time, which is why boosters and pregnancy vaccination matter.
Why it matters
Pertussis shows that a disease can remain common even when vaccines work. Waning immunity, missed vaccinations, delayed diagnosis, and mild breakthrough cases can keep transmission moving. The public-health goal is not only to reduce cough in older people, but to shield infants who have the least protection.
What public health teams watch
Health departments monitor reported cases, outbreaks, vaccination coverage, school and childcare clusters, infant hospitalizations, and close contacts. Response can include testing guidance, isolation advice, antibiotics for cases and selected contacts, vaccine catch-up, and clear communication to families and clinicians.