Test Vaccine Shows Promise Against Japanese Encephalitis
In trial, new vaccine shown at least equivalent in immunogenicity as existing, discontinued vaccine
MONDAY, Dec. 3 (HealthDay News) -- A novel inactivated vaccine for Japanese encephalitis virus provides at least an equivalent immunogenicity benefit as a licensed vaccine that is no longer being produced for developed countries, according to research published in the Dec. 1 issue of The Lancet.
Erich Tauber, M.D., of Intercell AG in Vienna, Austria, and colleagues analyzed data from a randomized, blinded phase III trial of a purified inactivated vaccine grown in Vero cells, made by Intercell Biomedical. Participants either received this vaccine (n = 430) or the licensed mouse-brain derived vaccine (n = 437).
At day 56 of the study, 98 percent of participants with the test vaccine showed seroconversion, compared to 95 percent of those with the licensed vaccine. The researchers also noted a geometric mean titre of 244 in the test vaccine group, compared with 102 for the licensed vaccine group. They reported no serious safety concerns with the test vaccine. The most common adverse events were headache, myalgia, flu-like symptoms and fatigue, which occurred at a similar rate in both groups.
"Given the limited sample size, short duration of follow-up, and limited population heterogeneity of prelicensure trials, vigilant postmarketing surveillance for safety and efficacy will be necessary," writes Marc Fischer of the U.S. Centers for Disease Control and Prevention, and colleagues in an accompanying commentary.
Several co-authors are employees of Intercell AG, which funded the study. Other institutions involved in the study received funding, which partly covered investigator salaries.