Immunogenicity, long term protection and safety of subcutaneous administration of hepatitis A vaccine in patients with hemophilia and other bleeding disorders: A randomized study

Abstract

Hepatitis A vaccine is recommended for all individuals with hemophilia, although patients with bleeding disorders should avoid intramuscular (IM) injections. To date, only few studies showed subcutaneous (SC) route immunogenicity is comparable with the IM route. Therefore, this randomized study compared immunogenicity, long term protection and safety of hepatitis A vaccine administered by SC route with the IM route in 78 children and adults with hemophilia and other bleeding disorders. Thirty-eight patients had serology performed after first vaccine dose, determining seroconversion rates of 83.3% and 90.0% for the SC and the IM group, respectively (p = 0.5). Median IgG CO/OD value for the SC group was almost the double compared with the IM group (4.4 vs 2.6, p = 0.2). After second vaccine dose, seroconversion rates for the SC group was 97.5% and for the IM group was 97.4% (p = 1.0). Of the two patients who did not have seroconversion, interval between vaccine dose and serology was only one and two days for the SC and the IM group, respectively and in the following routine antibody dosage they presented seroconversion (100% for both groups). Median IgG CO/OD value for the SC group was greater than the IM group (72.5 vs. 58.0, p = 0.2). In a median of nine years after second vaccine dose, median IgG S/CO value for the SC group was slightly greater than the IM group (7.6 vs. 7.4, p = 0.8). There were no serious adverse events in both groups. Five (12.5%) patients of the SC group and seven (18.4%) of the IM group presented adverse events (p = 0.5). Twice as many patients of the IM group had clotting factor concentrates need for adverse events (15.8% vs. 7.5%, p = 0.3). Therefore, hepatitis A vaccine administered subcutaneously is as immunogenic, long term protective and even safer than the intramuscular route.