Long-term immunogenicity of the new Vero cell-derived, inactivated Japanese encephalitis virus vaccine IC51 Six and 12 month results of a multicenter follow-up phase 3 study

• Published in: Vaccine Vol. 26; no. 34; pp. 4382 - 4386
• Main Authors: SCHULLER, E, JILMA, B, VOICU, V, GOLOR, G, KOLLARITSCH, H, KALTENBÖCK, A, KLADE, C, TAUBER, E
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier 12.08.2008; Elsevier Limited
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Animals; Antibodies, Viral - blood; Applied microbiology; Asia; Biological and medical sciences; Cercopithecus aethiops; Double-Blind Method; Encephalitis; Encephalitis Virus, Japanese - immunology; Female; Follow-Up Studies; Fundamental and applied biological sciences. Psychology; Humans; Immunization; Immunogenicity; Japanese Encephalitis Vaccines - immunology; Japanese encephalitis virus; Male; Microbiology; Middle Aged; Miscellaneous; Mortality; Neutralization Tests; Studies; Time Factors; Vaccines; Vaccines, antisera, therapeutical immunoglobulins and monoclonal antibodies (general aspects); Vaccines, Inactivated - immunology; Vector-borne diseases; Vero Cells; Virology; Asia; Australia; United States > US; Virus; Japanese encephalitis,Virus,Vaccine; Immunogenicity; Follow up study; Multicenter study; Japanese encephalitis virus; Vaccine; Japanese encephalitis group virus; Flaviviridae; Flavivirus; Inactivated strain
• ISSN: 0264-410X; 1873-2518
• DOI: 10.1016/j.vaccine.2008.05.081

Japanese encephalitis (JE) is the most common viral encephalitis in Asia. IC51 is a new Vero cell-derived, inactivated JE virus vaccine with non-inferior immunogenicity (after 2 months) compared to the US-licensed vaccine JE-VAX (mouse brain-derived, inactivated) and with a more convenient (two injections instead of three) intramuscular dose schedule. Adult subjects from two studies were followed-up for comparative immunogenicity (JE-VAX) at 6 months and long-term immunogenicity of IC51 alone at 12 months. At 6 months, immunogenicity was higher with IC51 (seroconversion rate [SCR] 95%; geometric mean titer [GMT] 84) than with JE-VAX (SCR 74%; GMT 34). At 12 months, the SCR was 83% and the GMT (41) remained above the protective titer of 1:10. Most people immunized with IC51 will have protective neutralizing antibody levels for at least a year.