Japanese encephalitis (JE) virus is the leading cause of vaccine-preventable encephalitis in Asia and the Western Pacific, which mainly invades central nervous system. Vaccination is the most important strategy to prevent JE. Currently, both live attenuated Japanese encephalitis vaccines (JE-L) and inactivated vaccines (JE-I) are in use. Due to the supply of vaccines and the personal choice of recipients, there will be a demand for interchangeable immunization of these two vaccines. However, relevant research is limited. By reviewing domestic and foreign research evidence, this article summarizes the current situation of the interchangeable use of JE-L and JE-I, and makes recommendations when the interchangeable immunization is in urgent need, so as to provide reference for practical vaccination and policymaking in China.
Encephalitis Virus, Japanese ; Encephalitis, Japanese/prevention & control* ; Humans ; Immunization ; Japanese Encephalitis Vaccines ; Vaccination ; Vaccines, Inactivated

The rate of Japanese encephalitis in Gia L­¬ng district was 21.4/100000, higher 4-5 times than other regions in the country. The disease occurred mainly in children under 15 years. After first 3 years (1993-1995) of injection, the rate of Japanese encephalitis was not reduced due to the rate of vaccination. However, because the rate of vaccination was increasingly during 1996-1999, the morbidity rate was gradually reduced from 21.4/100000 (in 1993) to 12.3/100.000 (in 1996) and 1.4/100.000 (in 1999). After 7 years of vaccination there was only one case received 2 injections of Japanese encephalitis vaccine suffered Japanese encephalitis among 109 total cases of Japanese encephalitis. The efficacy of vaccine of institute of epidemiology and hygiene was 99.3%.
Japanese Encephalitis Vaccines ; Injections ; prevention & control

We report a three-year-old Korean boy who presented with itching symmetrical erythematous macules and papules on his face, trunk, and extremities for 1 week. Lymphadenopathies were detected on physical examination. He was vaccinated against Japanese B Encephalitis (JE) 1 day before developing skin rashes. The patient's serum JE antibody titer by hemagglutinin inhibition (HI) test was 1:40. Under the diagnosis of Gianotti-Crosti syndrome following JE vaccination, he was conservatively treated with an antihistamine agent, and his symptoms were all cleared 2 weeks after treatment.
Acrodermatitis/*etiology ; Child, Preschool ; Encephalitis, Japanese/*prevention & control ; Human ; Japanese Encephalitis Vaccines/*adverse effects ; Male

Child ; China ; epidemiology ; Encephalitis Virus, Japanese ; Encephalitis, Viral ; epidemiology ; prevention & control ; Female ; Humans ; Japanese Encephalitis Vaccines ; immunology ; Male ; Vaccination

OBJECTIVETo explore on the immunity of live attenuated Japanese Encephalitis (JE) vaccine (SA14-14-2) to different wild JE virus (JEV) strains.

METHODSThe neutralizing effect of the vaccine against different wild JE virus strains was detected by plaque reduction neutralization test (PRNT), and the immunogenicity was studied on mice by vaccination -challenge protection test. In the PRNT, pooled sera from vaccinated human were tested against 10 strains of JEV, one isolated in Taiwan and 9 from other Asian countries. In the vaccination challenge test, mice received one dose of the live vaccine subcutaneously and were challenged intraperitoneally 14 days later against 22 JEV virus strains, 11 were isolated in China and the other 11 from Tailand, Vietnahailam, Indonesia, India, Philippines and Japan.

RESULTSThe protection rates to all the 22 challenge virus were 90% - 100% when 340 PFU/0.1 ml vaccinate virus was administered. The neutralizing effect showed that all the JEV isolates many have neutralized by the sera.

CONCLUSIONSA14-14-2 live attenuated prepared with strain SA14-14-2 is broadly immunogenic and may have effective protection against in Asian JE affected countries.

Adolescent ; Animals ; Child ; Encephalitis, Japanese ; prevention & control ; Humans ; Japanese Encephalitis Vaccines ; immunology ; Mice ; Neutralization Tests ; Vaccination ; Vaccines, Attenuated

Japanese encephalitis virus(JEV)is one of the leading cause of viral encephalitis in Asia. The phenotypic and genotypic characteristics of isolated virus strains are reviewed in this paper. Studies on the biological characteristics of the isolates showed that different isolates existed apparent differences in virus plaque morphology, neuroinvasive pathogenicity in mice, protective antigenicity and hemagglutination property. In China, only genotype III JEV strains were isolated before 1977. But since 1977, both genotype I and I JEV strains were isolated and the genotype I virus, which was isolated from mosquitoes mostly, has become the dominant strain. Study on the genomic sequence indicated that there was only a few amino acid difference (< or = 43%) between the two genotype isolates. Comparison between both genotype isolates and widely used live vaccine strain SA14-14-2 revealed that there were only < or = 3% amino acid differences, most of which were the SA14-14-2 unique attenuating sites. These results indicate that the SA14-14-2 live vaccine is able to protect people against infection of the both genotype I and Ill JEV strains.
Animals ; China ; Culicidae ; virology ; Encephalitis Virus, Japanese ; classification ; genetics ; immunology ; isolation & purification ; Encephalitis, Japanese ; immunology ; prevention & control ; virology ; Genome, Viral ; genetics ; Genotype ; Humans ; Japanese Encephalitis Vaccines ; immunology ; Mice ; Phenotype ; Species Specificity ; Vaccines, Attenuated ; immunology

Effective and tolerable vaccination is an essential strategy to prevent Japanese encephalitis (JE) in endemic areas. Although the live attenuated SA 14-14-2 JE vaccine (LAJEV) has been widely used since its introduction, the systemic data of LAJEV was very rarely available in Korea. We conducted the open-label, prospective cohort study to assess the immunogenicity and safety of this vaccine. Ninety subjects were enrolled, and LAJEV in a 2-dose primary series was given with a 12-month interval. Neutralizing antibody titers were measured before and after each vaccination, and active monitoring for adverse events was performed. After the first dose, 91.1% of subjects had seroprotection with a geometric mean titer (GMT) of 40.9. Seroprotection rate after the second dose was 97%, and GMT showed an increase of 6.5-fold. Most adverse events following immunization were self-limited, and no serious adverse events were reported until 42 days after each dose. The 2-dose administration of LAJEV in the primary immunization schedule appeared to be highly immunogenic and safe.
Antibodies, Neutralizing/analysis/immunology ; Antibodies, Viral/analysis/immunology ; Antibody Formation ; Child, Preschool ; Cohort Studies ; Encephalitis, Japanese/*prevention & control ; Female ; Humans ; Infant ; Japanese Encephalitis Vaccines/*immunology ; Male ; Prospective Studies ; Vaccination ; Vaccines, Attenuated/*immunology

To screen the best genotypeⅠJapanese encephalitis virus subunit vaccine candidate antigens, the prMEIII gene, the polytope gene and the prMEIII-polytope fusion gene of the GenotypeⅠJapanese encephalitis virus GS strain were cloned into prokaryotic expression vector pET-30a. The recombinant proteins were obtained after the induction and purification. The prepared recombinant proteins were immunized to mice, and the immunogenicity of the subunit vaccine candidate antigens was evaluated through monitoring the humoral immune response by ELISA, detecting the neutralizing antibody titer by plaque reduction neutralization test, and testing the cell-mediated immune response by lymphocyte proliferation assay and cytokine profiling. The recombinant proteins with the molecular weights of 35 (prMEIII), 28 (polytope antigen) and 57 kDa (prMEIII-polytope) induced strong humoral and cellular immune responses in mice. Compared with prMEIII-polytope and polytope proteins, the prMEIII protein induced a significant expression of IL-2 and IFN-γ (P<0.05) and the significant lymphoproliferation of splenocytes (P<0.05). The neutralizing antibody titer induced by the prMEIII protein was close to that induced by the commercial attenuated vaccine SA14-14-2 (P>0.05). The study suggests that the prMEIII protein can be used for the development of the Japanese encephalitis virus subunit vaccine.
Animals ; Antibodies, Viral ; blood ; Antigens, Viral ; immunology ; Encephalitis Virus, Japanese ; immunology ; Encephalitis, Japanese ; immunology ; prevention & control ; Immunogenicity, Vaccine ; Mice ; Mice, Inbred BALB C ; Vaccines, Subunit ; immunology ; Viral Vaccines ; immunology

OBJECTIVETo understand the immunological status of Japanese encephalitis (JE) antibodies amongst migrant workers and to provide epidemiological basis for public health strategies on JE prevention and control in Shenzhen.

METHODSA multi-stage random sampling method was used, and 1003 migrant workers aged 18 to 60 from 44 factories were investigated and their serum specimens were collected. The enzyme-linked immunosorbent assay (ELISA) was used to detect JE antibodies qualitatively.

RESULTSThe gross IgG seroprevalence rate for JE was 20.2% (203/1003). Sex-specified seroprevalence was 21.2% (103/485) for male and 19.3% (100/518) for female, respectively (χ(2) = 579, P > 0.05). Age-specific seropositive rates were 22.6% (12/53) for those below 20 years old, 18.7% (120/642) for those between 20-years old, 26.0% (58/223) for those between 30-years old and 15.3% (13/85) for those on or above 40 years old (χ(2) = 7.96, P > 0.05). Proportions for self-reported positive immunization, non-immunization and unclear immunization history were 22.1% (30/136), 22.1% (51/231) and 19.2% (122/636), respectively (χ(2) = 501, P > 0.05). Seroprevalence by region of origins showed that workers from Guangdong province was the highest (30.5%, 50/164), followed by workers from Guangxi (29.7%, 22/74) whilst workers from Shan(3)xi (5.4%, 2/37) had the lowest rate. Seroprevalence rate for managers (29.0%, 31/107) was higher than that of technicians (7.1%, 1/14) (χ(2) = 21.78, P < 0.05). Serological positive rate of workers with university or above educational background was the highest (32.7%, 16/49), followed by that for individuals with college degree (10.3%, 10/97) (χ(2) = 13.02, P < 0.05).

CONCLUSIONNo associations are detected between JE seroprevalence and age, or sex, or self-reported immunization histories amongst migrant labor workers in Shenzhen. However, correlations between JE serological positive rate and region of origins, occupation and educational attainment are found to be significant. The gross seroprevalence of JE antibodies suggests that the level of JE antibodies amongst Shenzhen migrant workers is low and the population immunity barrier has yet to be established. It is necessary to strengthen prevention and control strategies of JE among labor workers of Shenzhen.

Adolescent ; Adult ; Antibodies, Viral ; blood ; China ; epidemiology ; Encephalitis, Japanese ; epidemiology ; prevention & control ; Female ; Humans ; Japanese Encephalitis Vaccines ; administration & dosage ; Male ; Middle Aged ; Transients and Migrants ; statistics & numerical data ; Young Adult

Genes encoding for the premembrane and envelope (prME), envelope (E) and nonstructural protein (NS1) of Japanese encephalitis virus (JEV) were cloned. Each protein was expressed in baculovirus expression system. Of the three proteins expressed in baculovirus system, only prME had hemagglutination activity. The prME (72 and 54 kDa), E (54 kDa) and NS1 (46 kDa) proteins could be detected by Western blotting in the recombinant virus infected cells. Immunogenicity of the recombinant proteins obtained from infected Spodoptera frugiperda (Sf-9) cells was examined in mice. The 3 week-old ICR mice immunized intraperitoneally with three recombinant proteins three times were challenged with a lethal JEV. A survival rate was increased from about 7.7% in unimmunized mice to 92.3% in E + prME and only E groups. The complete protection was shown in prME and live vaccine inoculated groups, respectively. We also measured neutralizing antibody and three immunoglobulin subtypes of IgG1, IgG2a and IgG2b in the sera of mice before and after challenge. Titers of IgG1 antibodies were approximately two to three times higher than that of IgG2b antibodies in all the immunized groups as compared to the control group. However, IgG2a antibody level somewhat increased after challenge, indicating T-helper type 1 (Th1) cell response. The results of this study can provide useful information for developing efficacious subunit vaccine against JEV.
Animals ; Antibodies, Viral/blood ; Baculoviridae/genetics ; Blotting, Western ; Cloning, Molecular ; Encephalitis Virus, Japanese/genetics/*immunology ; Encephalitis, Japanese/*immunology/prevention&control ; Female ; Immunization ; Immunoglobulin Isotypes/blood ; Japanese Encephalitis Vaccines/*immunology/standards ; Mice ; Mice, Inbred ICR ; Microscopy, Fluorescence ; Plasmids ; Recombinant Proteins/genetics/immunology ; Viral Envelope Proteins/genetics/*immunology ; Viral Matrix Proteins/genetics/*immunology ; Viral Nonstructural Proteins/genetics/*immunology