The Role of Respiratory Virus Infection in Suspected Pertussis: A Prospective Study

Background: Pertussis is a disease caused by Bordetella pertussis (BP), being more frequent and severe in infants less than 1 year old. Respiratory viruses (RV) may mimic pertussis in infants.

Methods: A prospective cohort study with children under 1 year of age hospitalized with suspected clinical pertussis between 2014 and 2016 and submitted to etiological research to identify BP (nasopharynx swab for culture and/or PCR) and RV (nasopharyngeal aspirate for indirect immunofluorescence). Clinical, demographic and follow up data were collected.

Results: During the study period, 59 infants were analyzed. In 30.5% there was identification of BP, in 39% of some respiratory virus. In four (7%), there was BP detection and some RV. In the bivariate analysis they presented a greater chance of BP infection: lower age, no fever, not being vaccinated, leukocytosis > 20,000/mm³, lymphocytosis > 10,000/mm³ and RV infection: wheezing. After adjustment for confounders, the largest predictors for BP independently were: no wheezing (OR = 5.7) and leukocytosis > 20,000/mm³ (OR = 5.38). The number of patients with codetection did not allow the comparative analysis of severity with those with single agent.

Conclusion: Clinical/laboratory characteristics suggest, but are not pathognomonic, of the etiologies, which corroborates the need for VR and BP research in this clinical situation.