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DOI: 10.1093/cid/ciae085; PMCID: PMC11093674


BACKGROUND: Respiratory syncytial virus (RSV) is a leading cause of acute respiratory illnesses in children. RSV can be broadly categorized into 2 major subtypes: A and B. RSV subtypes have been known to cocirculate with variability in different regions of the world. Clinical associations with viral subtype have been studied among children with conflicting findings such that no conclusive relationships between RSV subtype and severity have been established.

METHODS: During 2016-2020, children aged/guardian interviews, chart reviews, and collection of midturbinate nasal plus/minus throat swabs for RSV (RSV-A, RSV-B, and untyped) using reverse transcription polymerase chain reaction.

RESULTS: Among 6398 RSV-positive children aged <5 >years, 3424 (54%) had subtype RSV-A infections, 2602 (41%) had subtype RSV-B infections, and 272 (5%) were not typed, inconclusive, or mixed infections. In both adjusted and unadjusted analyses, RSV-A-positive children were more likely to be hospitalized, as well as when restricted toseason, RSV-A and RSV-B cocirculated in varying levels, with 1 subtype dominating proportionally.

CONCLUSIONS: Findings indicate that RSV-A and RSV-B may only be marginally clinically distinguishable, but both subtypes are associated with medically attended illness in children agedFurthermore, circulation of RSV subtypes varies substantially each year, seasonally and geographically. With introduction of new RSV prevention products, this highlights the importance of continued monitoring of RSV-A and RSV-B subtypes.

Journal Title

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America





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MeSH Keywords

Humans; Respiratory Syncytial Virus Infections; Seasons; Infant; Child, Preschool; United States; Respiratory Syncytial Virus, Human; Male; Female; Prospective Studies; Hospitalization; Infant, Newborn; Respiratory Syncytial Virus Vaccines


RSV; RSV-A; RSV-B; hospitalization; seasonality


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