Nearly 40% of school age children in the United Kingdom who visit their family doctors with a persistent cough have evidence of whooping cough infection, even though they have been fully immunized, finds a study published on bmj.com.

These results suggest that whooping cough is endemic among young children in the UK, with important implications for clinical practice and immunization policy, say the authors.

Previous research in several countries has shown that Bordetella pertussis (whooping cough) infection is an endemic disease among adolescents and adults. Data also shows that neither infection nor immunization results in lifelong immunity, yet general practitioners in the UK seldom diagnose or even consider pertussis in older children. It is perceived as a disease of very young children who have not been immunized and who have classic cough features such as whoop.

The researchers identified 172 children aged 5-16 years who visited their family doctors with a cough lasting 14 days or more. Details on the duration and severity of cough were recorded, and immunization records were checked. Blood samples were taken to test for pertussis infection and parents and children also completed a cough diary.

A total of 64 (37.2%) children had evidence of a recent pertussis infection; 55 (85.9%) of these children had been fully immunized.

Children with pertussis were more likely than others to have whooping, vomiting, and sputum production. They were also more likely to still be coughing 2 months after the start of their illness, continue to have more than five coughing episodes per day, and cause sleep disturbance for their parents.

These results show that a substantial proportion of immunized school age children presenting to UK primary care with a persistent cough have evidence of a recent infection with Bordetella pertussis, say the authors.

They urge general practitioners to be alert to a potential diagnosis of pertussis in any child who presents with a persistent cough. A clear diagnosis will allow general practitioners to give parents an indication of the likely length of cough and prevent them from prescribing unnecessary drugs for asthma or referring children for further investigations, they conclude.

Click here to view full paper: [removed]http://press.psprings.co.uk/bmj/july/whoopingcough.pdf[/removed]