Long-term immunity and immune response to a booster dose following vaccination with the inactivated Japanese encephalitis vaccine IXIARO, IC51.
IC51 (IXIARO, JESPECT) is a recently approved prophylactic Japanese encephalitis virus vaccine with a two-vaccine primary immunization regimen. In this phase 3 trial, after primary immunization with a Day 0/28 dose schedule, seroprotection rates were 83%, 58% and 48% at Month 6, Month 12 and Month 24, respectively. A booster dose at Month 11 and/or Month 23 in subjects with neutralizing antibody titers below the limit of detection (defined as a serum dilution giving a 50% reduction of plaque counts in a plaque reduction neutralization test [PRNT50]<1:10) led to 100% seroconversion. After a single-dose immunization (incomplete primary immunization), only 9% of subjects were seroprotected at Month 6; however, a booster dose at Month 11 led to seroconversion in 99% of subjects. Hence, subjects with incomplete primary immunization can complete their schedule within at least 11 months.
Dubischar-Kastner
Katrin
K
Intercell AG, Campus Vienna Biocenter 3, 1030 Vienna, Austria. k.dubischar-kastner@intercell.com
Eder
Susanne
S
Buerger
Vera
V
Gartner-Woelfl
Gabriele
G
Kaltenboeck
Astrid
A
Schuller
Elisabeth
E
Tauber
Erich
E
Klade
Christoph
C
D000328:Adult; D000368:Aged; D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood; D004672:Encephalitis, Japanese / Q000276:immunology / Q000517:prevention & control*; D005260:Female; D005500:Follow-Up Studies; D005858:Germany; D006801:Humans; D007117:Immunization, Secondary; D022321:Japanese Encephalitis Vaccines / Q000009:adverse effects / Q000276:immunology*; D057230:Limit of Detection; D008297:Male; D008875:Middle Aged; D009500:Neutralization Tests; D009660:Northern Ireland; D055815:Young Adult
D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D022321:Japanese Encephalitis Vaccines