[Evaluation of Pertussis Cases in Our Hospital: Five-Year Analysis]

This study aimed to evaluate the demographic characteristics, seasonal distribution, clinical features, vaccination status and mortality rates of patients with Bordetella pertussis/parapertussis detected in our hospital between January 2019 and June 2024. Nasopharyngeal swab samples obtained using eSwab (Flocked swab, Copan Diagnostics, Italy) from patients who applied to our hospital with the complaints of upper/lower respiratory tract infection between January 2019 and June 2024 were tested in viral transport medium in our hospital’s microbiology laboratory using Film Array multiplex polymerase chain reaction (BioFire, bioMérieux Diagnostics, France) device in accordance with the manufacturer’s recommendations and the results were evaluated. Demographic characteristics of the patients, presenting complaints, follow-up in outpatient clinic/ward/intensive care unit, agents detected in nasopharyngeal samples, need for mechanical ventilation, vaccination status and recovery/death status were obtained from the Hospital Information Management System. In this study, B.pertussis was detected in 34 patients and B.parapertussis in 13 patients. Six of the patients were adults, 41 were in the pediatric age group and half of the pediatric age group (n= 20) were younger than six months. Vaccination information could not be obtained for six patients. Eighteen patients were unvaccinated, 17 were fully vaccinated for their age and six were incompletely vaccinated. While only five patients were detected during the coronavirus disease-2019 pandemic, 42 patients were detected in the post-pandemic period. It is particularly noteworthy that 20 cases were seen in the first six months of 2024. Eight patients in the pediatric age group were followed up in intensive care and four of them were younger than six months. In adult patients, three patients were followed up in intensive care and two were of advanced age (66 and 70 years). Eight of the patients admitted to the ICU required mechanical ventilation and five of these patients (three under six months, two two years old) died. In three of the patients who died, the causative agent was B.pertussis and they were unvaccinated and in two patients, the causative agent was B.parapertussis, one of these patients was unvaccinated and the other had four doses of the vaccine. As a result, it was determined that there was a significant increase in pertussis cases compared to the years, the number of cases doubled in the first six months of 2024 compared to the previous year, mortality increased especially in young children and infants, and most severe cases were unvaccinated. In addition, the loss of two out of 13 cases with B.parapertussis showed that infections due to B.parapertussis can also be severe and fatal. Besides, only one of the patients with B.parapertussis was unvaccinated, suggesting that the vaccine against B.pertussis does not provide cross-protection against B.parapertussis.