Characterization of circulating RSV strains among subjects in the OUTSMART-RSV surveillance program during the 2016-17 winter viral season in the United States

Abstract

BackgroundRespiratory syncytial virus (RSV) is an established cause of serious lower respiratory disease in infants, elderly and high-risk populations. The OUTSMART surveillance program aims to characterize patient populations and currently circulating RSV strains, and monitor temporal and geographic evolution of RSV F and G proteins in the U.S.MethodsThe OUTSMART 2016–17 study collected RSV-positive samples from 25 RSVAlert® laboratories from 4 U.S. regions and Puerto Rico during November 2016 through March 2017. Frequencies of A and B subtypes and genotypes were determined for several demographic and geographic variables. To gauge the representativeness of the OUTSMART patients, results were compared to discharge data from the NEDS and NIS databases.ResultsA total of 1,041 RSV-positive samples with associated demographic data were obtained and the RSV F gene and second variable region of the G gene were sequenced. The majority of samples (76.0%) came from children under 2 years old: <1 year (48.4%), 1–2 years (27.6%). The OUTSMART patient sample was similar to NEDS and NIS for age, gender, and geographic location. Both OUTSMART and national RSV cases peaked in January. Of OUTSMART samples, 45.3% were subtype A, 53.7% were subtype B and 1.0% were mixed A and B. The percentage of RSV B cases increased with increasing age. Hospitalization (length of hospital stay, LOS, >24 hrs) occurred in 29.0% of patients of which 52.0% had RSV B. Outpatients (LOS <24 hrs) were 64.4% of total of which 73.3% were diagnosed in the ER and discharged, while only 6% were diagnosed in other outpatient settings.ConclusionsThe OUTSMART 2016–17 study was representative of the U.S. RSV experience. Geographic and temporal information from the RSV surveillance program will be used to establish a molecular baseline of RSV F and G sequence variability and to help inform development of novel agents for RSV prophylaxis and treatment.

Respiratory syncytial, parainfluenza and influenza virus infection in young children with acute lower respiratory infection in rural Gambia

“…Unlike the seasonal circulation of RSV that is generally observed in temperate 16–18 and tropical climates 19–21 , RSV-A circulated almost throughout the year, similar to observations made in Senegal in 2012 and 2013 but not 2014 22 . PIVs, and IVs in particular, circulated for shorter periods of time.…”

“…PIVs, and IVs in particular, circulated for shorter periods of time. The predominance of one particular RSV type in one season, namely RSV-A in 2015, was similar to that observed in Mali (RSV-B in 2013) 23 , Senegal (RSV-B in 2012, RSV-A in 2013, RSV-B in 2014) 22 , Ghana (RSV-B in 2006 and 2013, RSV-A in 2014) 21 , and the United States (RSV- in 2015) 16 .…”

Epidemiology, Risk Factors, and Outcomes of Respiratory Syncytial Virus Infections in Newborns in Bamako, Mali

“…Studies on RSV subtypes from around the world have consistently found the RSV-A subtype to be more common; additionally, RSV-A is thought to have higher transmissibility than RSV-B [21–23]. While previous studies have found much variability in subgroups, and others have described a predominance of RSV-B during outbreaks [24], this is the first burden of disease study finding RSV-B as the dominant subtype, suggesting that RSV subtype selection may vary more between populations than previously thought.…”

Convergent structural features of respiratory syncytial virus neutralizing antibodies and plasticity of the site V epitope on prefusion F

“…The RSV genome encodes 11 proteins, two of which, surface proteins F and G, are the major targets of neutralizing and non-neutralizing antibodies. RSV can be further divided into subtypes A and B which co-circulate at approximately the same rate [ 12 ]. Subtype differences are based on antigenic and genetic variability of the G protein, whereas F maintains greater than 90% sequence identity between groups [ 12 , 13 ].…”