Serological evidence of pertussis in patients presenting with cough in general practice in Birmingham.

Three hundred and fifty-six patients in a large suburban practice (registered population 10,400), were diagnosed clinically with acute laryngitis/tracheitis or whooping cough (acute spasmodic cough of three weeks duration) between March 1996 and November 1997. Forty out of 145 who provided specimens for serological testing had evidence of recent infection with Bordetella pertussis. During the study a further 18 patients (mostly younger patients who presented early) had a diagnosis of pertussis confirmed by culture. Fifty-eight cases of pertussis in this population and time period was equivalent to an annual incidence of 330 per 100,000, whereas statutory notifications of pertussis in England and Wales suggested an incidence of less than 4 per 100,000 in the same period. Whooping cough remains an important cause of respiratory illness in all age groups. These results are a reminder for general practitioners to be alert to the diagnosis and a prompt to reconsider national vaccination policy.