Whooping cough runs in three stages, and only the second one sounds like it

Clinical pertussis has three stages, and knowing which one a patient is in
explains both the difficulty of diagnosis and the difficulty of control.

Stage 1: Catarrhal

• Coryza — a runny nose
• Low-grade fever
• A mild, occasional cough, gradually becoming more severe
• Apnea, in infants

This is a cold. Nothing distinguishes it from one, and this is when the patient
is most infectious — which is the central problem with pertussis control: the
window where transmission is highest is the window where nobody suspects
anything.

The infant entry is the exception that matters. **Apnea — pauses in
breathing — in place of a cough** is not a cold symptom, and in a small baby it
is the presentation.

Stage 2: Paroxysmal

The coughing fits, and the whoop on inhaling afterwards. This is the stage
the disease is named for and the stage at which it is usually recognised — by
which time the patient has been infectious for a fortnight.

Stage 3: Convalescent

Gradual recovery, with a cough that can persist for weeks.

Why age and vaccination status change everything

**Clinical presentation, complications, and risk of death can differ based
on age and vaccination status.**

A vaccinated adult may have a prolonged cough and nothing more. An
unvaccinated infant may never cough, may stop breathing, and may die. The same
organism produces both.

Which is why the advice for clinicians ends where it does: **follow the
recommended vaccine guidelines** — including in pregnancy and for anyone around
a newborn, since the infant who cannot be protected directly is protected by
the people holding them.

Source: Centers for Disease Control and Prevention.