Post-licensure comparative study of unusual high-pitched crying and prolonged crying following COMVAX™ and placebo versus PedvaxHIB™ and RECOMBIVAX HB™ in healthy infants

Background: In a previous clinical trial comparing COMVAX(TM) with its monovalent components, PedvaxHIB(TM) and RECOMBIVAX HB(TM), one of 92 comparisons of post-vaccination adverse experiences revealed a higher rate of unusual, high-pitched crying following the second, but not the first or third doses of COMVAX(TM) compared with two monovalent control vaccines. Rates of prolonged crying were similar between groups at each visit. Objectives: To compare the frequencies of unusual, high-pitched crying between recipients of COMVAX(TM) plus placebo and recipients of PedvaxHIB(TM) plus RECOMBIVAX HB(TM) following the second vaccine doses (primary) and to summarize the frequency of unusual, high-pitched crying and prolonged crying after each vaccination visit. Design: We enrolled 1215 healthy infants in a randomized, double blind, placebo-controlled study. Participating infants received study vaccines at 2 and 4 months of age and other routine childhood vaccines at 6-7 weeks and 3 months of age. Crying was evaluated via questionnaire at the time of enrollment (baseline) and daily from days 0 to 2 after each injection. Results: Reports of unusual, high-pitched crying and prolonged crying were uncommon (<1%) prior to the first vaccination visit and were comparable in both treatment groups. After each injection, rates of unusual, high-pitched crying (range: 4.26-6.96%) and prolonged crying (range: 0-1.36%) appeared similar between treatment groups and for each vaccination visit. Crying resolved in all infants; no neurological impairment was reported. Conclusion: This study found no statistically significant differences in rates of unusual, high-pitched crying and prolonged crying in infants vaccinated with COMVAX(TM) plus placebo compared with infants vaccinated with its monovalent components, PedvaxHIB(TM) and RECOMBIVAX HB(TM). (C) 2002 Elsevier Science Ltd. All rights reserved.