Respiratory Virus Surveillance in Infants Across Different Clinical Setting.

Objectives We aimed to evaluate the distribution, clinical presentations and severity of common acute respiratory infections (ARI) viruses in infants across three clinical settings. Study design In a prospective virus surveillance study, infants under one year with fever and/or respiratory symptoms were enrolled from outpatient (OP), emergency department (ED) and inpatient (IP) settings from 12/16/2019 through 4/30/2020. Demographic and clinical characteristics were collected through parent/guardian interviews, medical chart abstractions and follow-up surveys. Nasal swabs were collected and tested for viruses using qRT-PCR. Results We enrolled 366 infants and tested nasal swabs on 360 (98%); median age was 6.3 months, 50% male. In total, 295 (82%) had at least one virus detected; rhinovirus/enterovirus (RV/EV; 42%), respiratory syncytial virus (RSV; 34%), and influenza (15%) were the most common. RSV was the most frequently detected virus in the IP (63%) and ED (37%) settings, and RV/EV was most frequently detected virus in the OP setting (54%). RSV-positive infants had a lower median age (4.9 months), and were more likely to have respiratory distress, and RV/EV-positive infants were less likely to have respiratory distress. Influenza-positive infants had a higher median age (8 months) and were more likely to have systemic symptoms. RSV infection and younger age were associated with higher odds of hospitalization in multivariable logistic regression. Conclusion Across 3 clinical settings, and combining virological, patient and health-system information, our results highlight the burden of viral ARI among infants. Overall, RSV, RV/EV, and influenza were most commonly detected, with RSV having the highest disease severity.