Adenovirus Species in U.S. Children with Acute Respiratory Illness, 2016-2019.

Background: Human adenovirus (HAdV) is a common cause of pediatric acute respiratory illness (ARI). HAdV B, C, and E species have been associated with ARI, though relative detection frequencies in United States (U.S.) and respective roles in symptomatic respiratory infections remain unclear.

Methods: We conducted a multicenter, prospective viral surveillance study at seven U.S. children's hospitals comprising the New Vaccine Surveillance Network from 12/1/16-11/30/19. Children <18 years old in the emergency department or hospitalized with fever and/or respiratory symptoms were enrolled, and respiratory specimens were tested for HAdV and other viral pathogens. HAdV-positive specimens were subsequently typed using single-plex real-time PCR assays targeting sequences in the hexon gene. Demographics, clinical characteristics, and outcomes (hospitalization and supplemental oxygen use as severity indicators) were compared between HAdV-B and HAdV-C species.

Results: Of the 29,381 children with ARI, 1,843 (6.3%) had HAdV detected, with 1,402 specimens (76.0%) successfully typed. HAdV-C was the most frequently detected species (73.0%), followed by HAdV-B (22.3%). Children with HAdV-C were younger than those with HAdV-B and more likely to harbor another respiratory pathogen. Among children without other detected respiratory pathogens, those with HAdV-C had lower odds of hospitalization compared to children with HAdV-B (aOR: 0.44, 95% CI: 0.27, 0.73, p=0.001).

Conclusions: In our study among children seen in the emergency department or hospitalized with ARI, those with HAdV-C had lower odds of hospitalization compared to HAdV-B. These findings warrant further assessment to identify which HAdV types contribute to illness severity.