Leukocytosis and Delayed Macrolide Administration Were Risk Factors for Severe Pertussis in Newborn Infants.

AIM: This study investigated the epidemiological and clinical characteristics, diagnostic and therapeutic approaches and outcomes of neonatal pertussis cases hospitalised with coughs. We also aimed to identify the risk factors for severe pertussis.

METHOD: Newborn infants with coughs, who were admitted to Beijing Children's Hospital, China from November 2015 to October 2019, were retrospectively enrolled. Multivariable logistic regression analysis identified risk factors associated with pertussis.

RESULTS

The study comprised 714 infants and 39 had pertussis. The pertussis group exhibited earlier symptom onset, more rapid clinical progression and prolonged coughing than those without pertussis. Their mean white blood cell count was 20.1 ± 10.8 × 109/L, but 20.5% did not exhibit marked leukocytosis. Levels of immunoglobulin G antibodies against pertussis toxins were detected in 270 patients without pertussis and 77.8% showed a concentration of < 5 IU/mL. Risk factors for severe pertussis were delayed macrolide administration after symptoms appeared and leukocytosis. Serological testing for pertussis-specific antibodies was a powerful addition to conventional diagnostic methods.

CONCLUSION

Neonates with pertussis exhibited early symptoms, more rapid progression and prolonged coughing than infants without pertussis and risk factors for severe pertussis were leukocytosis and delayed macrolide administration. Serological antibody testing enhanced conventional methods.