Whooping cough: the hundred-day cough

What it is, in plain words

Whooping cough is a bacterial infection of the airway lining by Bordetella pertussis. The bacteria paralyse the tiny hairs that clear mucus, so it accumulates and can only be shifted by violent bursts of coughing. The whoop is the sound of air rushing back in after such a burst.

Signs to look out for

• One to two weeks of an ordinary-looking cold
• Then paroxysms: long runs of coughing without breathing in, ending in a whoop or vomiting
• Cough far worse at night, often with a normal examination between fits
• In babies under six months: pauses in breathing, blue episodes and poor feeding, often with no whoop at all
• A dry cough lingering for weeks to months as it slowly resolves

Why it happens

Immunity from vaccination or infection fades after several years, so adolescents and adults become the reservoir and infect infants who are too young to be fully vaccinated.

How doctors confirm it

PCR on a nasopharyngeal swab is the test of choice in the first three weeks; serology helps later. Blood count may show a high lymphocyte count in infants.

Treatments and solutions

• Macrolide antibiotics, which shorten contagiousness and help if started in the first three weeks, though they do little for a cough already established
• Preventive antibiotics for close contacts, particularly households with infants or pregnant women
• Hospital admission for infants under six months, for monitoring of breathing and feeding
• Small frequent feeds, upright positioning and calm environment to reduce paroxysms
• Vaccination: the childhood schedule, adolescent boosters, and a dose in every pregnancy between 20 and 32 weeks, which protects the newborn through the placenta

Living with it day to day

Cough medicines, steroids and bronchodilators do not work here. Time and protection of the vulnerable are what matter.

When to seek medical help

Go to hospital for any infant with pauses in breathing, blue colour, poor feeding, or a cough with vomiting and exhaustion.

This article explains general health information in simple language. It does not replace advice from your own doctor.