COMPARATIVE SAFETY OF 2 RECOMBINANT HEPATITIS-B VACCINES IN CHILDREN - DATA FROM THE VACCINE ADVERSE EVENT REPORTING SYSTEM (VAERS) AND VACCINE SAFETY DATALINK (VSD)

Background: Preliminary review of data from the Vaccine Adverse Event Reporting System (VAERS), 1991-1994, revealed that more serious advers e events were reported in children who received a specific brand of re combinant hepatitis B (HepB) vaccine. Objective: To compare the post-m arketing safety experience of the two recombinant HepB vaccines licens ed for use in infants and children in the United States. Design: Revie w of a case series derived from passive surveillance data in the natio nal VAERS. A retrospective cohort study using data from one health mai ntenance organization participating in Vaccine Safety Datalink (VSD), a computerized record linkage system. Populations Studied: U.S. Childr en, ages birth-10 year for whom adverse events after HepB vaccine were reported to VAERS, 1991-1994. Children, ages birth-6 years, who recei ved HepB vaccine at Kaiser Permanente Medical Care Program, Northern C alifornia, 1991-1994. Main Outcome Measures: VAERS reporting rates for each vaccine by manufacturer were calculated from the numbers of repo rted events occurring within 30 days of HeB vaccination and the number of doses distributed by the manufacturers. VSD event rates for each v accine were calculated from the numbers of hospitalization or emergenc y room visits within 30 days of HepB vaccination and the number of vac cine doses administered to the cohort. Results: In VAERS, higher rates of serious events (i.e., life threatening or resulting in hospitaliza tion or permanent disability) were reported in children who received V accine A vs. Vaccine B (relative risk [RR]: 3.13-8.18, P < 0.01), part icularly by those vaccinated in the private (RR: 7.62-28.58, P < 0.01) , but not public sector (RR: 2.12, P = 0.19). Similar types of events were reported in recipients of both vaccines. In contrast, analysis of VSD data showed no significant difference in rates of hospitalization or ER visits in children who received either HepB vaccine (RR: 0.96-1 .25, P > 0.05). Conclusions: Our investigation reveals that it is unli kely there is a true difference between rates of serious events tempor ally associated with the two HepB vaccines in children. This study dem onstrates the dual roles played by VAERS and VSD in providing a more c omplete picture of the post-marketing safety profile of childhood vacc ines, and underscores the importance of using other analytic studies t o evaluate findings from passive surveillance systems of adverse event s. (C) 1998 Elsevier Science Inc.