Combined typhoid fever and hepatitis A vaccine: comparison of immunogenicity and safety to concomitant monovalent vaccine over 3 years.

Background: The safety and immunogenicity of Viatim, a combined hepatitis A (HA) and typhoid fever (Vi) vaccine, were compared with the monovalent component vaccines up to and 1 month after a booster dose at 3 years.

Methods: Healthy, adult volunteers were randomized to receive Viatim (group A, n = 179) or separate HA and Vi vaccines (group B, n = 181); subgroups were boosted after 3 years with Viatim (groups C and D, n = 56 and 46, respectively). Local and systemic reactions were recorded for 28 days postvaccination.