A hard-to-shift cough may be caused by a highly contagious bacterial infection of the lungs and airways thought to mainly affect children. Whooping cough, also known as pertussis, spreads easily and can be serious.

Initial symptoms can be a runny nose and sore throat, but it can then develop into bouts of coughing which last for minutes and are worse at night. Thick mucus can also be brought up. The name comes from the "whoop" sound which might be heard as sufferers gasp for breath between coughs. It can last for weeks or even months, according to the NHS.

While the infection is deemed to mostly affect babies and children, studies suggest some six in 10 infections occur in adults. It is passed mainly through coughs and sneezes.

In England, the UK Health Security Agency says cases rose by over 1,600% in 2024 compared to 2023.

Professor Andrew Preston, a microbiologist at the University of Bath, told the MailOnline that whooping cough used to be regarded as a disease of young babies and children.

But he said it is becoming increasingly clear adults are affected too, adding: "For these adults, the main symptom is typically a chronic cough."

Professor Preston said while it is possible more adults are being infected with whooping cough than before, it may also be the case that adults have always been susceptible, but medics never realised as the only sign was a long-lasting cough and GPs did not test for it.

The NHS says whooping cough can be dangerous, especially for babies under 12 months, who have an increased chance of developing breathing difficulties, pneumonia and fits.

It is less severe in older children and adults, although coughing can lead to sore ribs, hernia, middle ear infections and incontinence when coughing.

If a child's lips, tongue, face or skin suddenly turn blue or grey, people are advised to call 999 or go to A&E. They should also do this if your child is having fits or if you or your child find it hard to breathe or have chest pain.

Severe cases of whooping cough can require hospital treatment if a baby is under six months.

Antibiotics can be given if whooping cough is diagnosed within two weeks of a cough starting, but these might not reduce symptoms, according to the NHS.

Whooping cough sufferers should get lots of rest, drink plenty of fluids and take paracetamol or ibuprofen if experiencing discomfort. Children under the age of 16 should not be given aspirin.

There is a vaccine for whooping cough which is given routinely as part of the six-in-one vaccine and the four-in-one pre-school booster. Women who are pregnant should also get vaccinated. This usually happens at about 20 weeks.

Professor Preston suggested the six-in-one jab is a very potent vaccine which protects children from the worst of the illness.

But he said it also allows the infection to keep spreading, adding it wears off over time so most of the effects have gone by adulthood.

Although, the vaccine change may not be the reason adults are getting whooping cough, as some experts argue the bacteria causing it has always been prevalent in adults, it just wasn't tested for.