• Pediatric Infection and Vaccine
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• v.15 no.2
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• pp.108-114
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• 2008

Japanese encephalitis is the leading cause of viral encephalitis in Asia, where it accounts for up to 50,000 cases. Approximately 20% of affected patients die, and 30-50% of survivors have significant neurological sequelae. Inactivated mouse-brain derived Japanese encephalitis vaccines has been effectively implemented to control the disease effectively in Korea and several other Asian countries. However, the vaccine is expensive and difficult to produce, requires multiple doses, and has been associated with hypersensitivity reactions and rare adverse neurologicale events. The live-attenuated SA14-14-2 vaccine derived from primary hamster kidney (PHK) cells was developed in China and has been used there since 1988. Outside China, it has been licensed and used in Korea and several other Asian countries. This vaccine is effective and inexpensive. However, the lack of precedence for using a PHK cell substrate in a live-attenuated vaccine is a special issue of concern. The WHO working group has recommended additional safety studies in selected high-risk groups, as well as ongoing post-marketing studies to ensure long-term safety. Recently, a new inactivated vaccine and live-attenuated chimeric vaccine have been developed from vero cells. With this background, this article summarized the current status of Japanese encephalitis vaccination worldwide and in Korea.

• Biomolecules & Therapeutics
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• v.5 no.2
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• pp.174-178
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• 1997

The immnunogenicity of the possible non-essential component of the combined vaccine (KGCC-957) for the prophylaxis against Japanese encephalitis and Hantaan virus infection recently developed by Korea Green Cross Corporation was investigated using the Hartley guinea pigs. The KGCC-95Vl was administered to the guinea pigs subcutaneously to sensitize the animals. The guinea pigs did not induce any anaphylactic immune responses which could be detectable by the active systemic anaphylaxis (ASA), the passive systemic anaphylaxis (PSA), and the passive cutaneous anaphylaxis (PCA) tests. The KGCC-95Vl is considered not to induce any anaphylactic immune responses except the prophylatic immune effects of the vaccine.

• Clinical and Experimental Pediatrics
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• v.65 no.3
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• pp.108-114
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• 2022

The Japanese encephalitis (JE) virus is the leading cause of vaccine-preventable encephalitis in Asia. Since the introduction of a universal JE vaccination program and urbanization of Korea, the incidence of JE has dramatically decreased in Korea. However, recent JE cases have occurred, predominantly among unvaccinated adults and with a shift in age distribution. Here we aimed to review the changes in age-specific JE seroprevalence over time and discuss the implications of JE vaccination programs in Korea. Following the last epidemic in 1982-1983, mandatory vaccination for all children aged 3-15 years was conducted annually until 1994. However, JE has reemerged, predominantly affecting unvaccinated adults aged 40 years or older and demonstrating a shift in age distribution toward older populations. The age-specific seroprevalence of the JE virus in Korea has changed noticeably over time. Seropositivity in children and adolescents increased from 10%-59% in the 1970s to 90%-92% in the 1980s after the implementation of the JE vaccination program and increased further to 98% in 2012. No age-specific difference in the seroprevalence of JE was found, and appropriate levels of immunity to JE were maintained for all age groups. Continuous surveillance of the seroprevalence of JE is essential to establish a proper immunization policy in Korea.

• Journal of Microbiology and Biotechnology
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• v.32 no.8
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• pp.955-959
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• 2022

Japanese encephalitis (JE) is a vaccine-preventable mosquito-borne disease caused by infection with the Japanese encephalitis virus (JEV). JEV has five genotypes, including genotype V (GV), which is considered ancestral to the other genotypes. The first GV strain, GV Muar, was isolated from a Malayan patient in 1952 and GV did not reappear for 57 years until GV XZ0934 was isolated from a mosquito sample in China. Since 2010, 21 GV strains have been identified in Republic of Korea (ROK). Both GV Muar and GV XZ0934 are more pathogenic than other GI/GIII strains and are serologically distinct. However, because the ROK's GV strains have not been experimentally tested, their characteristics are not known. Characterization of the ROK's isolates is needed to enable development of effective GV strain-based vaccines to protect against GV infections.

• The Journal of the Korean Society for Microbiology
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• v.16 no.1
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• pp.83-89
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• 1981

Japanese encephalitis has been prevalent for long time in the Far East and many patients have been reported in both South East and Mid-West Asia recently. Recently, vaccine was used in prevention of this viral disease of man which was derived from formalin inactivated virus inoculated into mouse brain, but live attenuated active vaccine for human is not developed yet. Author inoculated Japanese encephalitis virus into several cell culture strains for development of live attenuated encephalitis virus strain and the results were as follows: 1. Japanese encephalitis virus was inactivated rapidly in cell free medium at $36^{\circ}C$ and totally inactivated by 72 hours. 2. In growth curve of Japanese encephalitis virus in HeLa cell cultures, maximal multiplication of the virus was occured at 4th day and virus multiplication was continued for at least 12 days. 3. After succeeding passage of the virus in HeLa cell cultures and human esophagus epithelial cell cultures, infectivity of virus for mice was disappeared from 2nd passage in HeLa cell cultures and 3rd passage in esophagus epithelial cell cultures. 4. In inoculation to monkey kidney epithelial cells and chick embryo cell cultures, infectivity of the virus for mice was continued after 10th passages.

• Toxicological Research
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• v.13 no.1_2
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• pp.157-160
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• 1997

The primary skin and eye irritancy of the combined vaccine (KGCC-95VI) for the prophylaxis against Japanese encephalitis and Hantaan virus infection recently developed by Korea Green Cross Corporation was investigated. The KGCC-95VI was applied to the back skins of the New Zealand White rabbits. The rabbits were observed for 72 hours and did not exhibit erythema, eschar and edema. The eyes of the rabbits were exposed to the KGCC-95VI. The rabbits were observed for 7 days and did not exhibit any ocular findings on cornea, iris and conjuntivae. The KGCC-95VI is considered not to have the primary skin and eye toxicity in rabbits.

• Korean Journal of Veterinary Service
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• v.35 no.3
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• pp.169-174
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• 2012

Japanese encephalitis virus (JEV) is one of the main causes of viral encephalitis in human and animals. For over 30 years, a live attenuated JEV vaccine strain has been used in the veterinary field, and it is required to conduct quality evaluation studies on the commercial vaccines. For the quality control of live attenuated JEV vaccine, we investigated the nucleotide sequence similarity of prME gene derived from five JEV vaccines commercially available in pigs in Korea. The Vero cells infected with JEV vaccines showed specific cytopathic effect, which was characterized by rounding and detached cells. In the phylogenetic analysis, all of the vaccine strains showed a close relationship with the original vaccine seed strain (Anyang 300) and clustered into the genotype 3. In comparison of the nucleotide and deduced amino acid sequences of prME genes with the original strain, all JEV vaccine strains showed high amino acid similarity ranging from 98.9% to 99.5%, but had several point mutations, probably due to high mutation rates of viral RNA polymerase by several virus passages. Even though the current JEV vaccine strains have been maintained and produced for a long period of time, the genetic characterization of them have been rarely changed. However, since the mid 1990's, molecular epidemiology of JEV has been changed sharply from genotype 3 to genotype 1 in Korea, further studies on new vaccine strains to genotype 1 is required for more effective prevention in the field.

• Pediatric Infection and Vaccine
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• v.5 no.1
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• pp.67-68
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• 1998

• Toxicological Research
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• v.13 no.3
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• pp.275-279
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• 1997

The acute toxicity of the combined vaccine (KGCC-95VI) for the prophylaxis against Japanese encephalitis and Hantaan virus infection. recently developed by Korea Green Cross Corporation, was investigated. KGCC-95VI was administered to the Balb /c mice in two routes, orally and subcutaneously, and into the New Zealand White rabbits subcutaneously. $LD_{50}$ was not accessible as there were no deaths in the group treated even at a dose 800 times the expected clinical dose in both animal species. Between the treated and control groups there were no statistically significant differences in body weight changes and clinical signs during the 14-day observation period, and no pathological gross findings. Accordingly KGCC-95VI is considered not to have the acute toxicity in mice and rabbits.

• Toxicological Research
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• v.13 no.4
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• pp.353-357
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• 1997

The possibility of the allergic encephalomyelitis caused by the combined vaccine (KGCC95VI) for the prophylaxis against Japanese encephalitis and Hantaan virus infection, recently developed by Korea Green Cross Corporation, was investigated in the Hartley guinea pigs. The KGCC-95VI was administered to the guinea pigs subcutaneously to sensitize the animals three times at one month intervals. There were no clinical signs or gross pathological findings. There were no abnormal histopathological findings at cerebrums, cerebellums, brain stems and the spinal cords. The concentration of myelin basic protein was 1.10 ng/dose quantified by ELISA, which met the guide4ine of below 2 ng/ml/dose recommended by American Society of Health -System Pharmacists(AHPS) Drug Information. Accordingly, the KGCC-95VI is considered not to induce any allergic immune responses which may lead to the experimental allergic encephalomyelitis.