Malignant Pertussis With COVID-19 Coinfection in an Unvaccinated Infant: A Case Report in the Context of Vaccine Hesitancy.

Pertussis remains a major cause of morbidity in infants worldwide despite widespread vaccination. Coinfection with respiratory viruses such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may exacerbate disease severity and complicate management. We report a case of malignant pertussis in a one-year and five-month-old boy complicated by a concurrent coronavirus disease 2019 (COVID-19) infection. The child presented with prolonged paroxysmal cough, leukocytosis, and respiratory distress requiring non-invasive ventilation. Bordetella pertussis was confirmed by nasopharyngeal aspirate polymerase chain reaction (PCR). The patient also tested positive for SARS-CoV-2. He was managed with supportive care and dual antibiotic therapy, with gradual clinical improvement and normalization of white cell count. This case highlights the diagnostic and therapeutic challenges of pertussis in the setting of co-infection and delayed immunization.