BACKGROUND: There are no data on the use of inactivated Vero cell culture-derived Japanese encephalitis (JE) vaccine (JE-VC) as a booster among individuals who previously received inactivated mouse brain-derived JE vaccine (JE-MB). METHODS: Military personnel who received ≥3 doses of JE-MB or were JE vaccine-naïve were vaccinated with 2 doses of JE-VC on days 0 and 28. Serum neutralizing antibodies were measured pre-vaccination and 28 days after each dose. Non-inferiority was evaluated for seroprotection rate and geometric mean titer (GMT) between previously vaccinated participants post-dose 1 and vaccine-naïve participants post-dose 2. RESULTS: Fifty-three previously vaccinated and 70 JE vaccine-naïve participants were enrolled. Previously vaccinated participants had significantly higher GMTs pre-vaccination, post-dose 1, and post-dose 2. Seroprotection rates among previously vaccinated participants post-dose 1 (44/44, 100%) were noninferior to those achieved in previously naïve participants post-dose 2 (53/57, 93%). The GMT was significantly higher in previously vaccinated participants post-dose 1 (GMT 315; 95% CI 191-520) compared to previously naïve participants post-dose 2 (GMT 79; 95% CI 54-114). CONCLUSIONS: Among military personnel previously vaccinated with ≥3 doses of JE-MB, a single dose of JE-VC adequately boosts neutralizing antibody levels and provides at least short-term protection. Additional studies are needed to confirm these findings in other populations and determine the duration of protection following a single dose of JE-VC in prior recipients of JE-MB. Published by Elsevier Ltd.
BACKGROUND: There are no data on the use of inactivated Vero cell culture-derived Japanese encephalitis (JE) vaccine (JE-VC) as a booster among individuals who previously received inactivated mouse brain-derived JE vaccine (JE-MB). METHODS: Military personnel who received ≥3 doses of JE-MB or were JE vaccine-naïve were vaccinated with 2 doses of JE-VC on days 0 and 28. Serum neutralizing antibodies were measured pre-vaccination and 28 days after each dose. Non-inferiority was evaluated for seroprotection rate and geometric mean titer (GMT) between previously vaccinated participants post-dose 1 and vaccine-naïve participants post-dose 2. RESULTS: Fifty-three previously vaccinated and 70 JE vaccine-naïve participants were enrolled. Previously vaccinated participants had significantly higher GMTs pre-vaccination, post-dose 1, and post-dose 2. Seroprotection rates among previously vaccinated participants post-dose 1 (44/44, 100%) were noninferior to those achieved in previously naïve participants post-dose 2 (53/57, 93%). The GMT was significantly higher in previously vaccinated participants post-dose 1 (GMT 315; 95% CI 191-520) compared to previously naïve participants post-dose 2 (GMT 79; 95% CI 54-114). CONCLUSIONS: Among military personnel previously vaccinated with ≥3 doses of JE-MB, a single dose of JE-VC adequately boosts neutralizing antibody levels and provides at least short-term protection. Additional studies are needed to confirm these findings in other populations and determine the duration of protection following a single dose of JE-VC in prior recipients of JE-MB. Published by Elsevier Ltd.
Authors: Ki Wook Yun; Hoan Jong Lee; Jin Han Kang; Byung Wook Eun; Yae-Jean Kim; Kyung-Hyo Kim; Nam Hee Kim; Young Jin Hong; Dong Ho Kim; Hwang Min Kim; Sung-Ho Cha Journal: BMC Infect Dis Date: 2015-01-08 Impact factor: 3.090