The potency of 33 lots of Japanese encephalitis vaccine produced during the year period 2000-2001 at the Company for Vaccine and Biologicals No1 was evaluated by Shewhart chart. Data showed that no any potency of these lots falls outside the range of one standard deviation 1SD. Results showed the good stability of production procedure, the efficacy of produced vaccine of the manipulation and of the practical conditions
Japanese Encephalitis Vaccines ; Encephalitis

The pilot study was performed on the first 5 lots of the Japanese encephalitis vaccine produced by Beijing-1 strain: JB011203, JB021203, JB030104, JB040204 and JB050304 to evaluate their safety and potency. The quality control consists of abnormal toxicity, specific safety, pyrogen, sterility and potency test. All of 5 lots were passed the minimum requirements of biological products of Japan. The mice and guinea pigs were healthy, body weigh increased. Non of bacteria and fungi grown in both medium Thioglycholate and Soybeancasein. The pyrogen test on rabbits was passed in 5/5 lots. Summed temperature response of 3 rabbits per lot were 0°C-0.3°C (WHO requirement ≤1.4°C). Potency test was evaluated by PRNT compared with reference EJP034A of BIKEN. After the second immunization the neutralizing antibody response > reference from 0.04 to 0.2 log. 5/5 lots were passed the safety and potency test and met the minimum requirement of biological products of WHO.
Japanese Encephalitis Vaccines ; Vaccines

159 lots of JE vaccine, which produced from 1994 to 1999, have been tested for chemical components including total protein, thimerosal, formaldehyde and pH. All of the 159 lots meet the WHO's minimal requirements for JE vaccine. Basing on the obtained results, WHO's requirements for chemical components of JE vaccine can be used for JE vaccine produced in Vietnam.
Japanese Encephalitis Vaccines ; chemistry

For 4 consecutive years 1997-2000, immunization with Japanese encephalitis (JE) vaccine produced by the NIHE has been extended into the 90 high risk districts of the Northern region. 1.219.779 out of 1.296.248 children aged 1-5 years were immunized with two doses of JE vaccine, a total of 94.1% and 833.199 out of 878.643 children aged 1-5 years were also immunized with a booster dose achieving a coverage of 94.83%. There were no complications reported after JE immunization. Disease surveillance results in these districts showed that: the incidence of JE has decreased each year and from 1995 to 2000 the incidence was reduced 2.4 times.
Japanese Encephalitis Vaccines ; Immunization

262 children aged 6-14 years old were randomly divided into 4 groups receiving different vaccine doses of 1ml; 0,75ml; 0,1 ml. After the interval of one week between two injections the results showed that antibody response manifested effectively on all 4 groups.
Japanese Encephalitis Vaccines ; Immunization

Using white Swiss mouse at 3-4 weeks of age for injection of Japanese Encephalitis (JE) virus. Every 8 lots of the mouse had been infected with Nakayama and Beijing-1 strains by injection of 0.03ml into their brains, then followed up within 3 days. The paralysed mice were collected at the 69th hour of the beginning and at the 120th hour of the end. The interval between collection time was every 3 hours. In this study, the rate of mice with paralysis due to Beijing-1 strain was higher than those due to Nakayama strain (94.99% and 92.97%, respectively). The authors suggested that use of Beijing-1 strain to produce JE vaccine is more effective than Nakayama strain.
Japanese Encephalitis Vaccines ; Mice

42 lots of Japaness encaphalitis virus were purified from viral infected rat brain mixture, for obtaining 28 lots of vaccine products. All lots of vaccine were met WHO standard through local and national laboratory qualification ultracentrifugal 126000 g within 5 hours demonstrated that saturated ammonium sulphate precipitated procedure had removed 26.4% to 32% of protein, then ultricentyrifugal sucrose had removed almost the rest. Protein contents in producted vaccine reached 6.53-61.3%
Encephalitis, Japanese ; Encephalitis Virus, Japanese ; Viruses ; Vaccines

On 293 healthy children of 2-4 years old of age in the Commune Song Ho, Thuan Thanh District, Bac Ninh Province, of them 101 children were vaccinated with Vietnam produced vaccine and 102 with Biken vaccine. Results showed that Vietnam produced vaccine manifested an antibody response of 100% with Tb antibody valent (GMT) of 3.48. After 1 year of basal immunization, GMT decreased by 2.49 but it was still higher than 2.5 times of minimal value and after the 3rd injection of vaccines GMT increased by > 4.01 times higher than the basal immunization level. In comparing with Biken vaccine, the Vietnam produced vaccine has a GMT antibody response rate and a long duration of life of antibody with high level comparable to the Japan produced vaccine
Child ; Encephalitis, Japanese ; Japanese Encephalitis Vaccines

The outcomes of vaccination in 1 to 5-year children were surveyed in high-risk districts between 1997 and 2001. The Japanese encephalitis vaccination schedule as follows: In the first years, the children receive 2 injections with 1-week interval, in the next year they receive the third injection. The injection dose is 0.5 ml subcutaneous. Results: For 5 years continuously, there were 1,472,608 one to five-year children had immunized, reached rate of 94.7% in 90 high-risk districts. The program produced dramatic effect on prevention. The incidence of Japanese encephalitis dropped gradually over years. By 2002, the cases reduced by one third in comparison with previous time
Encephalitis, Japanese ; Encephalitis Viruses, Japanese ; Japanese Encephalitis Vaccines

10 batches of Japanese encephalitis vaccine (JEV) produced at (NIHE) during 1998 were investigated for antigen content. The results showed that: JE antigen content of these 10 batches was equal or slightly higher than that of the reference vaccine
Japanese Encephalitis Vaccines ; Antigens ; vaccines