Immune Response and Antibody Persistence against Hantaan Virus of Vaccinees with Hantavax(TM) / 감염

ABSTRACT

BACKGROUND: Hantavax(TM) was developed for preven-tion of hemorrhagic fever with renal syndrome caused by Hantaan or Seoul virus in 1990, and has been commer-cially available in Korea since then. Because Hantavax (TM) has such short usage history, the duration of antibody persistency in vaccinees has not been well studied. METHODS: 61 healthy people were immunized subcu-taneously with Hantavax (TM) twice at one month intervals as primary vaccination. 21 vaccinees were tested at 1 ~4 months after primary vaccination and 40 vaccinees were tested at one year after primary vaccination and then one month and 1 ~2 years after booster vaccination. Antibody titers were measured by immunofluorescent assay(IFA), Hantaan virus antigen-coated high density particle agglu-tination assay(HDPA), and plaque reduction neutralization test(PRNT). RESULTS: Seroconversion rates of 21 vaccinees at 1 ~ 4 months after primay vaccination were 20/21(95.2%), 19/21(90.5%) and 14/21(66.7%); seropositivity of 40 vaccinees at one year after primary vaccination was 25/40 (62.5%), 18/40(45.0%), and 9/40(22.5%) by IFA, HDPA, and PRNT, respectively. Seroconversion rates of 8 vaccinees at one month after booster vaccination were 8/ 8(100 %), 8/ 8(100%); antibody persistence rate of 11 vaccinees at 20 months after booster vaccination were 11/ 12 (91.7%), 9/ 12(75.0%), and seroconversion rates of 7 vaccinees at 3 months after second booster vaccination were 7/7(100%) and 6/7(85.7%) by IFA and PRNT, respectively. Geometric mean antibody titers of 21 vaccinees at 1-4 months after primary basic vaccination were 262, 248, 120; and those of 40 vaccinees at one year after primary vaccination were 90, 56, and 24 by IFA, HDPA, and PRNT, respectively. Geometric mean antibody titers of 8 vaccinees at one month after booster vaccination were 852, 183, of 12 vaccinees at 20 months after booster vaccination were 296, 33, and of 7 vaccinees at 3 months after second booster vaccination were 549 and 46 by IFA and PRNT, respectively. CONCLUSION: The booster vaccination is necessary at 12 months after primary vaccination to maintain high levels of antibodies which persist at least two years after booster vaccination.