Randomized, Double-Blind, Placebo-Controlled Phase 3 Trial of the Safety and Tolerability of IC51, an Inactivated Japanese Encephalitis Vaccine

• Published in: The Journal of infectious diseases 2008-08, Vol.198 (4), p.493-499
• Main Authors: Tauber, E., Kollaritsch, H., von Sonnenburg, F., Lademann, M., Jilma, B., Firbas, C., Jelinek, T., Beckett, C., Knobloch, J., McBride, W. J. H., Schuller, E., Kaltenböck, A., Sun, W., Lyons, A.
• Format: Article
• Language: English
• Subjects: Adult; Aged; Arboviral encephalitis; Arboviroses; Biological and medical sciences; Double-Blind Method; Encephalitis Virus, Japanese - immunology; Encephalitis Virus, Japanese - metabolism; Encephalitis, Japanese - prevention & control; Experimentation; Female; Fundamental and applied biological sciences. Psychology; Headache; Human viral diseases; Humans; Immunization; Infectious diseases; Japanese encephalitis; Japanese encephalitis vaccines; Japanese Encephalitis Vaccines - administration & dosage; Japanese Encephalitis Vaccines - adverse effects; Japanese Encephalitis Vaccines - immunology; Japanese encephalitis virus; Japanese encephalitis viruses; Male; Medical sciences; Microbiology; Middle Aged; Placebos; Safety; Tropical medicine; Tropical viral diseases; Urticaria; Vaccination; Vaccines, Inactivated - administration & dosage; Vaccines, Inactivated - adverse effects; Viral diseases; Viruses
• ISSN: 0022-1899; 1537-6613
• DOI: 10.1086/590116

Background. Japanese encephalitis (JE) is the most important mosquito-borne viral encephalitis and has a high case fatality rate. It is caused by Japanese encephalitis virus. Improved vaccines are urgently needed for residents in countries of endemicity, travelers, and the military. The aim of the present trial was to evaluate the safety and tolerability of IC51, Intercell's Vero cell-derived, purified, inactivated JE vaccine. Methods. This was a randomized (3:1), double-blind, placebo-controlled, multicenter phase 3 trial. Healthy subjects were randomized to receive 2 doses of IC51 (n=2012) or placebo (n=663) at a 4-week interval. Adverse events following immunization (AEFI) were documented over a period of 2 months. Results. The rate of severe AEFI was similar in the IC51 group (0.5%) and the placebo group (0.9%). The rate of medically attended AEFI and all AEFI was also similar in the IC51 group and the placebo group. The same applied for all adverse events, including local and systemic tolerability. Importantly, there were no signs of acute allergic reactions. Conclusion. The Intercell JE vaccine IC51 had a safety profile similar to that of placebo. These data, together with the immunogenicity data from a recent phase 3 trial, form the basis of application for licensure of this vaccine. Trial registration. ClinicalTrials.gov identifier: NCT00605058.