Variation in severity of respiratory syncytial virus infections with subtype

• Published in: The Journal of pediatrics Vol. 117; no. 1; pp. 52 - 62
• Main Authors: McConnochie, Kenneth M., Hall, Caroline B., Walsh, Edward E., Roghmann, Klaus J.
• Format: Journal Article
• Language: English
• Published: United States Mosby, Inc 01.07.1990
• Subjects: Age Factors; Carbon Dioxide - blood; Confounding Factors (Epidemiology); 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; New York
• ISSN: 0022-3476; 1097-6833
• 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<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.