Bordetella pertussis infection in a highly vaccinated population in Saudi Arabia, 1996–2004

SummaryObjectivesThe objective of this study was to describe the features and presentations of Bordetella pertussis infection at Saudi Aramco Medical Services Organization (SAMSO) in Saudi Arabia.MethodsThis is a retrospective analysis of the reported cases of B. pertussis from January 1996 to December 2004.ResultsDuring the study period, there were a total of 156 confirmed cases of B. pertussis infection. There were 88 males and 68 females, with male to female ratio of 1.3:1. Most (n = 81; 52%) of the patients were less than six months of age. A large number (n = 71; 45.5%) of patients were reported in 2003; 26.8% (n = 19) were between 10–19 years and 22.5% (n = 16) were ≥20 years of age. Of all the patients, 65 (42%) patients were hospitalized for a median of five days (range: 2–21 days). Of the total cases, 47 (30%) patients were fully vaccinated (≥3 doses), 48 (30%) had not received any dose of vaccine, 33 (21%) had received one dose and six (3.8%) had received two doses. The vaccination status was not known for 22 (14%) patients. However, many of the infected infants were too young to have been eligible for vaccine. A total of 81 patients were less than six months of age and of those 58% (n = 47) did not receive any doses, 39.5% (n = 32) received one dose and 2.5% (n = 2) received two doses.ConclusionIn this sample of cases of whooping cough arising in the highly vaccinated population of Saudi Arabia, the overwhelming majority of cases were infants less than six months of age and older adults.