One arm or two? Concurrent administration of meningococcal C conjugate and hepatitis B vaccines in pre-teens.

BACKGROUND: The purpose of this study was to: (a) compare rates of local reactions from meningococcal C conjugate (Neis Vac-C) and hepatitis B vaccines (Recombivax HB), and (b) compare local reactions when both injections were given in one arm versus one in each arm. METHODS: Schools were randomized to have grade six students receive both vaccines in one arm (One Arm Group), or one vaccine in each arm (Two Arm Group; MCC always given in left arm). Structured telephone interviews of parents were conducted, and respondents were asked about local and systemic reactions, interference with school or other activities, need for medical attention, and lost parental work time. FINDINGS: The Two Arm Group reported significantly more local redness >46 mm (6.5% vs. 0.5%, p < 0.001), moderate to severe tenderness (28% vs. 18%, p < 0.05), and drowsiness (14% vs. 7%, p < 0.05). When adjusted for sex, ethnicity, and town of residence, report of any tenderness was associated with town of residence only; moderate or severe tenderness was independently associated with the Two Arm Group (OR 1.4, 95% CI 1.1-1.85). There were no statistically significant differences between groups for interference with school attendance or other activities, need for medical attention, or lost parental work time. Among participants of the Two Arm Group (188 students), there was more redness (6% vs. 2%, p < 0.05) and tenderness (54% vs. 32%, p < 0.001) experienced with Neis Vac-C than with Recombivax HB, respectively. CONCLUSIONS: Injecting two vaccines in one arm did not cause more local reaction than one injection in each arm and remains an option for those who prefer it for logistical reasons, If vaccinating in two arms, Neis Vac-C should preferentially be given in the nondominant arm.