Variation in severity of respiratory syncytial virus infections with subtype

J Pediatr. 1990 Jul;117(1 Pt 1):52-62. doi: 10.1016/s0022-3476(05)82443-6.


Two major subtypes of respiratory syncytial virus have been identified. This study assessed the hypothesis that A-subtype infections were more severe than B-subtype infections among the 157 infants hospitalized in two hospitals in Rochester, N.Y., during two winters. Severity was measured both by specific clinical observations and by a severity index that was derived empirically. Among all subjects, several clinical observations suggested that A-subtype infections were more severe. For example, mechanical ventilation was required in 12.6% of those with A-subtype compared with 1.6% of those with B-subtype infection (relative risk = 7.88; p = 0.01). Among high-risk infants (infants with underlying conditions or age 3 months or less at admission), carbon dioxide tension greater than 45 mm Hg was found in 37.0% of those with A-subtype compared with 12.0% of those with B-subtype infection (relative risk = 3.08; p = 0.04). In discrete multivariate (logit) analysis, effects of subtype (odds ratio = 6.59; p less than 0.01) on severity remained after adjustment for other statistically significant effects of age less than 3 months, underlying condition, and premature birth. The finding that A-subtype infections were more severe might have important implications for vaccine development, studies of the virulence of respiratory syncytial virus, clinical management (e.g., selection for antiviral therapy), and long-term prognosis.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Age Factors
  • Carbon Dioxide / blood
  • Confounding Factors, Epidemiologic
  • Humans
  • Infant
  • Infant, Newborn
  • Infant, Premature
  • Multivariate Analysis
  • New York / epidemiology
  • Oxygen / blood
  • Population Surveillance
  • Pulse
  • Respiration / physiology
  • Respiratory Syncytial Viruses / classification*
  • Respiratory Tract Infections / blood
  • Respiratory Tract Infections / epidemiology*
  • Respiratory Tract Infections / physiopathology
  • Respirovirus Infections / blood
  • Respirovirus Infections / epidemiology*
  • Respirovirus Infections / physiopathology
  • Risk Factors


  • Carbon Dioxide
  • Oxygen