MORE than 12,000 cases of whooping cough were confirmed in England in the first seven months of the year, UK Health Security Agency data shows.
A UKHSA spokesperson said: "Whilst monthly case numbers in 2024 have fallen since May, pertussis activity remains high and may increase after children in England return to school in September."
A total of 12,200 Brits knowingly fell ill with the bacterial infection, officially called pertussis, between January and July this year.
This compares to 856 provisional laboratory-confirmed cases in the whole of 2023.
More than half of this year's cases (56.2 per cent) were in those aged 15 and above.
A fifth (20.1 per cent) were in children aged 10 to 14, and 11.7 per cent were in five- to nine-year-olds.
The number of confirmed infections in babies under three months, who are at highest risk of severe disease and too young to be fully vaccinated, stands at 379 - almost eight times as many as in 2023.
Nine infants have lost their lives to whooping cough in 2024. One died last year.
Dr Alison Cave, chief safety officer at the Medicines and Healthcare products Regulatory Agency, said: "Returning to school after the summer holidays is a busy time for children, parents and schools alike.
"However, it's important to always make sure children's health is as best protected as possible.
"From childhood vaccinations to asthma inhalers and adrenaline autoinjectors, it's the perfect time to take stock of your child's medicines and medical devices, and make sure they are as safe as possible as they start the new school year."
The UKHSA added: "The recent increase in pertussis cases has been observed across all age groups and in every region in England.
"Case numbers rose across the first five months of 2024 to May, as expected based on usual seasonal patterns, and remained high in June and July.
"Confirmed cases in the second quarter of 2024 were notably high, exceeding those in any quarter of the 2012 outbreak year."
Whooping cough is a bacterial infection of the lungs and breathing tubes that spreads easily and can be serious.
Symptoms tend to be similar to a cold, such as a runny nose and sore throat, plus bouts of coughing that last for a few minutes and get worse at night.
Some people make a "whoop" sound as they gasp between coughs, while others bring up thick mucus and become very red in the face.
The condition may last for several weeks or months, so it is often dubbed the "100-day cough".
In some people, coughing fits can be so severe that they fracture ribs.
Babies under six months are most at risk of problems such as breathing difficulties, seizures and pneumonia, the NHS warns.
The best way to protect against whooping cough is vaccination, the health service adds.
The pertussis jab is included in the '6-in-1 vaccine' given to babies at eight, 12 and 16 weeks old, and the 4-in-1 pre-school booster for children aged three years four months.
It is also offered to expectant mothers who are 16 to 32 weeks pregnant.
However, vaccination rates have fallen in the UK since the Covid pandemic.
The latest UKHSA data on the maternal whooping cough vaccine programme shows that uptake has dropped dramatically.
In December 2017, 74.7 per cent of pregnant women, babies and young children took up the offer of the vaccine.
But figures for March 2024 suggest just 58.9 per cent were jabbed.
A UKHSA spokesperson said: "Vaccination in pregnancy is key to passively protecting babies before they can be directly protected by the infant vaccine programme.
"Pertussis vaccination is recommended in every pregnancy and women should normally receive their whooping cough vaccine around the time of their mid-pregnancy scan (usually 20 weeks) but can receive it from 16 weeks.
"To help provide optimal protection, the vaccine should be given before 32 weeks; but women who miss out can still have the vaccine later.
"It is also important that babies are vaccinated on time when they become eligible for infant doses at eight, 12 and 16 weeks of age and that those who miss vaccination are caught up at the earliest opportunity."
If you or your child does fall ill - particularly if you have a cough for more than three weeks, or one that is getting worse - the NHS advises you to speak to your GP.
Anyone diagnosed in the first three weeks of symptoms may be given antibiotics, but after this point, they are not considered helpful.
Instead, sufferers are urged to get plenty of rest, stay hydrated, and take paracetamol or ibuprofen.
If you or your child experiences significant breathing problems, fits or signs of pneumonia, call 999 or visit A&E.
The most common symptoms of pneumonia - inflammation of the lungs, usually caused by an infection - are a cough, shortness of breath, a high temperature, chest pain and an aching body.