Prospective safety monitoring of Haemophilus influenzae type b and heptavalent pneumococcal conjugate vaccines in Kagoshima, Japan

Haemophilus influenzae type b (Hib) conjugate vaccine (PRP-T) and heptavalent pneumococcal conjugate vaccine (PCV7) were introduced in Japan in December 2008 and February 2010, respectively. The concurrent administration of these vaccines is routinely performed worldwide. However, the safety of the simultaneous administration of these vaccines has not been fully evaluated in Japan, because it has rarely been performed thus far.We conducted a 2-year prospective, observational, multicenter study on PRP-T and PCV7 safety from February 2009 through January 2011 in 29 facilities located in Kagoshima Prefecture, Japan. Objective severe adverse events included anaphylactoid reaction, encephalitis/encephalopathy, neurological events, severe focal reactions, systemic eruption/urticaria, fever above 399C within 2 days after inoculation, and other complications requiring hospitalization. The incidences of these events for PRP-T and PCV7 administration were 0.68z (76/11,197) and 0.92z (28/3,049), respectively. No deaths or subsequent complications were reported during the course of the study. There was no significant difference in the incidence of severe adverse events between the single and co-administration groups for both vaccines: PRP-T, 0.55z (31/5,662) versus 0.81z (45/5,535; P = 0.11); PCV7, 0.88z (11/1,247) versus 0.94z (17/1,802; P = 0.86). These results suggest that the simultaneous administration of vaccines including PRP-T and/or PCV7 does not increase the incidence of severe adverse events in Japanese children.