Here is exactly what you need to know about how the symptoms develop: from day one to day 100.

1

The bug, known as pertussis, is a fast-spreading bacterial infection of the lungs and breathing tubes.

A fall in vaccination rates is leaving more children in hospital with the illness.

Between July and the end of December 2023, there were 856 suspected cases of whooping cough in England and Wales.

This is nearly 600 more than the equivalent timeframe in 2021 and 2022.

Dr Simon Theobalds, a GP from Manchester, said: “Most viral infections last one to two weeks, but for some people it may be longer.

“There are various reasons for this, and this includes the different levels of immunity against infections that we have.”

According to the US Centre for Disease Control and Prevention, the notoriously long illness progresses through three stages.

The symptoms usually start five to 10 days after you catch the bug.

These are likely similar to the common cold, such as a minor headache, runny nose, sore eyes, sneezing, and a slight temperature.

After two weeks, those with the bug will experience intense coughing, which can last several minutes at a time.

These coughing fits usually worsen and become more common as the illness develops.

Sometimes, coughs will be followed by an audible ‘whoop’ sound – which gives the illness its name.

The coughing can bring up thick mucus, which can cause people to be sick.

Young children or babies might turn blue or grey due to difficulty breathing, while adults might become red in the face.

If you or your child’s lips, tongue, face or skin suddenly turns blue or grey, call 999 or go to A&E at once.

By week eight, the violent cough would have developed into something milder.

Sufferers can then be left with a chronic cough for several weeks.

For many months, they are also likely to be more susceptible to other respiratory infections, like colds and the flu.

“If symptoms persist or worsen and you feel more unwell or have high fevers, we recommend a GP appointment to have a full assessment and rule out more serious conditions such as pneumonia or sepsis,” Dr Simon added.

Ask for an urgent appointment or call NHS 111 if:

• Your cough is very bad or gets worse very quickly
• You feel very unwell
• You have chest pain
• The side of your neck feels swollen or painful
• You find it difficult to breathe
• You cough up blood

If you do have whooping cough, antibiotics can help – but only if you start taking them within three weeks of your symptoms starting, the NHS says.

The best way to protect your family from it is by getting vaccinated.

The illness is most dangerous to newborn babies and infants. 

Babies under six months old are at risk of dehydration, brain swelling, pneumonia, and seizures.

Up to three per cent of those under three months die from the illness.

Older children and adults can also experience pneumonia, sore or fractured ribs due to intense coughing, hernias, middle ear infections and urinary incontinence.

How to tackle it

There is usually no need to see a GP if you have a cough, according to the NHS.

But you should rest, drink plenty of fluids, and avoid contact with others.

Painkillers like paracetamol or ibuprofen can also be taken, as well as hot lemon and honey drinks and herbal medicine called pelargonium (if over the age of 12).

Pharmacists can also advise on the best cough syrups, medicines, sweets, and supplements.