title: Severity of respiratory syncytial virus infection is related to virus strain.
abstract: The relationship between respiratory syncytial virus (RSV) strain and disease severity was assessed in 265 hospitalized infants over a 3-year period (1988-1991). A severity index of clinical and physiologic parameters was used to grade illness severity. Multivariate analysis of 134 infants infected with group A RSV strains and 131 infants infected with group B strains indicated that prematurity, underlying medical conditions, group A RSV infection, and age < or =3 months were independently associated with severe disease. Odds ratios for severe disease for these risk factors were 1.83, 2.84, 3.26, and 4.39, respectively. Among infants without underlying medical conditions, group B RSV infection rarely required ventilatory support, in contrast to group A infections (1/90 vs. 13/107; P < .006), and had significantly lower severity indices (mean +/- SD, 0.6 +/- 9 vs. 1.3 +/- 1.9; P = .05). Results confirm earlier findings that group A RSV infection results in greater disease severity than group B infection among hospitalized infants.
authors.affiliation: Department of Medicine, University of Rochester School of Medicine and Dentistry, New York, USA.
authors.forename: E E
authors.initials: EE
authors.lastname: Walsh
authors.forename: K M
authors.initials: KM
authors.lastname: McConnochie
authors.forename: C E
authors.initials: CE
authors.lastname: Long
authors.forename: C B
authors.initials: CB
authors.lastname: Hall
mesh_terms: D005260:Female; D006760:Hospitalization; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D018357:Respiratory Syncytial Virus Infections / Q000821:virology*; D012136:Respiratory Syncytial Viruses / Q000145:classification*