Table 2.

Summary of Analysis of RSV Hospitalization

PlaceboPalivizumab% Reduction (95% CI)P Value
Primary analysis (incidence of RSV hospitalizations)*53 /500 (10.6%)48 /1002 (4.8%)55% (38, 72)<.001
Alternative analysis (Kaplan-Meier)53 /500 (10.6%)48 /1002 (4.8%)55% (38, 72)<.001
Sensitivity analyses
 Dropout before 150 days and no endpoint53 /500 (10.6%)49 /1002 (4.9%)55% (38, 72)<.001
 Respiratory hospitalization but no RSV test done§56 /500 (11.2%)54 /1002 (5.4%)52% (35, 69)<.001
Primary inclusion populations
 Premature (no BPD)19 /234 (8.1%) 
 9 /506 (1.8%)
78% (66, 90)<.001
 BPD34 /266 (12.8%)39 /496 (7.9%)
39% (20, 58).038
  • Abbreviations: RSV, respiratory syncytial virus; CI, confidence interval; BPD, bronchopulmonary dysplasia.

  • * Fisher's exact test.

  • Kaplan-Meier estimate of the proportion at 150 days. Deaths before RSV hospitalization, withdrawals, and lost events were treated as censored.

  • The number of children who stopped follow-up before day 150 and had no endpoint through the last follow-up visit and would have been hospitalized if the proportion hospitalized was equal to that of the other treatment group added to observed incidence of RSV hospitalization. For placebo 5 children × 0.048 (RSV hospitalization rate in palivizumab group) = 0.24 (0 added events); for palivizumab 11 children × 0.106 (RSV hospitalization in placebo) = 1.17 (1 added event).

  • § Number of children with respiratory hospitalizations and evidence of infection (coryza, fever) who had no alternative etiology added to observed incidence of RSV hospitalization. Three no antigen respiratory hospitalizations (0.6%) in the placebo group and 6 (0.6%) in the palizivumab group.