Bloodstream Infections in Children Hospitalized for Influenza, the Canadian Immunization Monitoring Program Active.

ABSTRACT

BACKGROUND: We aimed to estimate the proportion of children hospitalized for influenza whose illness was complicated by bloodstream infection, describe their clinical course, and identify the factors associated with bloodstream infection. METHODS: We performed active surveillance for laboratory-confirmed influenza hospitalizations among children ≤16 years old at the 12 Canadian Immunization Monitoring Program Active hospitals, from the 2010-2011 to 2020-2021 influenza seasons. Factors associated with bloodstream infection were identified using multivariable logistic regression analyses. RESULTS: Among 9179 laboratory-confirmed influenza hospital admissions, bloodstream infection occurred in 87 children (0.9%). Streptococcus pyogenes (22%), Staphylococcus aureus (18%) and Streptococcus pneumoniae (17%) were the most common bloodstream infection pathogens identified. Children with cancer [adjusted odds ratio (aOR) 2.78; 95% confidence interval (CI) 1.23-5.63], a laboratory-confirmed nonbloodstream bacterial infection (aOR 14.1; 95% CI 8.04-24.3) or radiographically-confirmed pneumonia (aOR 1.87; 95% CI 1.17-2.97) were more likely to experience a bloodstream infection, whereas children with chronic lung disorders were less likely (aOR 0.41; 95% CI 0.19-0.80). Disease severity markers such as intensive care unit admission (aOR 2.11; 95% CI 1.27-3.46), mechanical ventilation (aOR 2.84; 95% CI 1.63-4.80) and longer hospital length of stay (aOR 1.02; 95% CI 1.01-1.03) were associated with bloodstream infection. Bloodstream infection also increased the odds of death (aOR 13.0; 95% CI 4.84-29.1) after adjustment for age, influenza virus type and the presence of any at-risk chronic condition. CONCLUSIONS: Bloodstream infections, although infrequent, are associated with intensive care unit admission, mechanical ventilation, increased hospital length of stay and in-hospital mortality, thus requiring increased levels of care among pediatric influenza hospitalizations.