Adult pertussis in a general practice

To examine serologically the incidence of pertussis in a group of adults (> 15 years of age) presenting to their General Practitioner with symptoms which suggested the possibility of pertussis.

One year's study of the results of testing blood samples. This was followed by a questionnaire to the General Practitioners involved, asking information on all the patients tested.

Specimens were tested as part of the normal workload in the Microbiology Department of a District General Hospital.

The patients all attended a Health Centre in South Lanarkshire which caters for a population of 12,749 people.

Twenty of fifty six patients tested (35.7%) produced serological evidence of recent pertussis infection. The average age of the positive patients was 43.5, and the duration of their symptoms, before testing, was 4.2 weeks. The results suggest that pertussis in adults is not uncommon. Symptoms of "whoop" and/or vomiting were seldom reported in this series. "Paroxysmal coughing", "nocturnal coughing", and "shortness of breath" were more common in the positive cases than in the negative ones. The use of antibiotics did not appear to have any beneficial effect, probably due to them being given too late after the onset of infection. Most adults are susceptible to pertussis, as vaccine-induced immunity declines and is absent after 12 years following vaccination. In a vaccinated population, adults are now the primary source of infection for susceptible infants.