• 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.

• Korean Journal of Veterinary Service
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• v.46 no.3
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• pp.193-202
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• 2023

Porcine epidemic diarrhea is an infectious intestinal disease caused by the porcine epidemic diarrhea virus (PEDV). Especially, when suckling piglets are infected, the mortality rate is close to 100%. PEDV is classified into G1 and G2 types based on genetic differences. The G2 type PEDV outbreak in the United States in 2013 was highly pathogenic and contagious, and it has spread worldwide and caused continuous economic losses. Most commercial vaccines used are G1 type vaccines, and existing vaccines do not fully protect piglets due to genetic differences. In this study, we evaluated the safety of the newly developed G2 type attenuated HSGP vaccine strain by inoculating it into piglets and testing whether the vaccine virus spreads to the non-vaccinated, negative pigs and whether the vaccine reverts to its virulence during serial passage experiments. Each experiment lasted for 7 days for each passage, and fecal viral titers, clinical symptoms, and weight gain were measured daily. After the experiment, necropsy was performed to measure intestinal virus titer and pathological evaluation. As a result of the first passage, no transmission of the vaccine virus to negative pigs co-housed with vaccinated pigs was observed. In addition, after four consecutive passage experiments, the clinical symptoms and small intestine lesions were gradually alleviated, and no virus was detected in the feces in the fourth passage experiment. Therefore, it was concluded that the vaccine was safe without virulence reversion in accordance with the guidelines of the current licensing authority. However, further studies are needed on the genetic changes and biological characteristics of the mutant virus that occur during successive passages of the attenuated vaccine since the replication and clinical symptoms of the virus increased until the third passage during successive passages of the vaccine virus. Based on this study, it was concluded that virulence reversion and safety evaluation of attenuated vaccines through serial passage in target animals can be useful to evaluate the safety of attenuated viruses.

• IMMUNE NETWORK
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• v.2 no.1
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• pp.1-5
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• 2002

Estimated number of adults and children newly infected with HIV-1 during 2001 alone is 5 million in total. An effective vaccine, in addition to education & public health approaches, has been believed to be the best option to stop the HIV-1 transmission, especially for developing countries. Among AIDS vaccine candidates, DNA vaccine is relatively safe and, in a certain extent, mimics some attributes of live attenuated vaccine, with regard to in vivo gene expression & the type of immunity induced. We recently demonstrated that DNA vaccines expressing SIVmac239 structural and regulatory genes, augmented with coadministration of IL-12 mutant induced the strongest T cell responses, resulting in low to undetectable setpoint viral loads, stable $CD4^+$ T cell counts, and no evidence of clinical diseases or mortality by day 420 after challenge. This finding is the second demonstration, following the protective result of live attenuated SIV vaccine in SIVmac-rhesus monkey model, which was known to have safety problem. So, our DNA vaccines could give a significant impact on HIV-1 epidemic by slowing or stopping the spread of HIV-1, leading to eventual eradication of HIV-1 and AIDS in the population.

• KSBB Journal
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• v.25 no.6
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• pp.497-506
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• 2010

Vaccine is a protective clinical measure capable of persuading immune system against infectious agents. Vaccine can be categorized as live attenuated and inactivated. Live attenuated vaccines activate immunity similar to natural infection by replicating living organisms whereas inactivated vaccines are either whole cell vaccines, eliciting immune response by killed organisms,or subunit vaccines, stimulating immunity by non-replicating sub cellular parts. The components of vaccine play a critical role in deciding the immune response mediated by the vaccine. The innate immune responds against the antigen component. Adjuvants represent an importantcomponent of vaccine for enhancing the immunogenicity of the antigens. Subunit vaccines with isolated fractions of killed and recombinant antigens are mostly co-administered with adjuvants. The delivery system of the vaccine is another essential component to ensurethat vaccine is delivered to the right target with right dosage form. Furthermore, vaccine delivery system ensures that the desired immune response is achieved by manipulating the optimal interaction of vaccine and adjuvantwith the immune cell. The aforementioned components along with routes of administration of vaccine are the key elements of a successful vaccination procedure. Vaccines can be administered either orally or by parenteral routes. Many groups had made remarkable efforts for the development of new vaccine and delivery system. The emergence of new vaccine delivery system may lead to pursue the immunization goals with better clinical practices.

• Korean Journal of Veterinary Research
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• v.58 no.3
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• pp.137-141
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• 2018

The efficacy of the CA-2-MP120 vaccine, a cell culture-attenuated strain of virulent porcine reproductive and respiratory syndrome virus (PRRSV), was assessed in pigs. Despite the persistence of viremia in all vaccinated animals during the immunization period, the virus was not detected in vaccinated pigs following challenge. Furthermore, no pigs in the vaccinated group shed PRRSV nasally, orally or rectally throughout the experiment. Moreover, histopathological lung and lymph node lesions in the immunized group were much milder than those in the unimmunized and challenged group. These results indicated that CA-2-MP120 can provide effective protection against virulent wild-type PRRSV-2.

• Korean Journal of Veterinary Research
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• v.39 no.4
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• pp.778-785
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• 1999

To detect CDV RNA in clinical samples and differentiate prevailing CDV virulent strains affecting susceptible animals from attenuated vaccine strains, we performed RT-PCR, RFLP, and sequencing. CDV specific primers were generated from the middle part of nucleocapsid gene. The expected size of PCR products, 519 bp, was observed in tissues of Jindo dog, poodle dog, badger, fourteen of nineteen blood samples as well as 5 vaccine strains including domestic and imported products. The PCR products obtained from tissues and PBMCs of infected animals were digested to 317- and 202-bp fragments by Bam HI, but the products obtained from four of five vaccine strains and Lederle strain were not digesed by Bam HI. Only one vaccine strain of which the PCR products were digested by Bam HI was confirmed as imported vaccine, modified Synider Hill strain. Based on seqencing data obtained from the 519-bp products, it was confirmed that Bam HI restriction site tends to be conserved in field isolates compared to the commercially available attenuated vaccine strains. Partial nucleotide sequences of CDV NP gene obtained from tissues of Jindo dog, poodle and badger shared 100% homology each other, whereas the nucleotide sequences showed 96.3, 96.5, 93.6 and 93.4% homology with Yanaka (virulent), Han95 (virulent), Lederle (attenuated) and Onderstepoort (attenuated) strain, respectively.

• Korean Journal of Veterinary Research
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• v.2 no.1
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• pp.27-36
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• 1962

Immune response to two methods of Newcastle disease virus vaccine, one inactivated and the other attenuated was observed and the data presented. (1) Administration of inactivated virus vaccine in an amount of 1.0 ml. by intramuscular route gave an appreciable immunity to Newcastle disease for a period of at least three-and-half months. (2) The chickens given attenuated virus vaccine in the drinking water produced satisfactory immunity as manifested by the fact that immunized birds showed resistance when challenged 105 days after the vaccination and maintained high degree of HI titer for a period of 75 days. (3) Vaccination with the attenuated virus vaccine in drinking water is very simple and time saving in procedure, although the duration of immunity seems to be slightly shorter than that proced by inactivated virus vaccine. The author wishes to express his appreciation, to Drs. Kyu Myung Lee, Chang Koo Lee, and Ryong Sook Kee of their suggestions and help. The author is also indebted to Dr. Chang Hi Lee, Director of Anyang Veterinary Laboratory, who allowed the use of the facilities of the laboratory, whitout which this experiment could not have been undertaken.

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

• Korean Journal of Veterinary Research
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• v.51 no.3
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• pp.193-201
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• 2011

An attenuated vaccine strain AVR1/08 of Korean respiratory type of infectious bronchitis virus (IBV) was developed by 89th passages of IBV D85/06 strain in chicken eggs. The AVR1/08 strain had higher virus titer at least 20 times ($10^{1.3}$) than the parent virus D85/06 by egg inoculation method. The AVR1/08 strain had a single point mutation (S to Y) at position 56 of spike protein of IBV compared to parent virus IBV D85/06 strain. The mutation was observed consistently at viruses after 47th passage in chicken eggs. The AVR1/08 strain showed no virulence even after 6 passages in chickens and all chickens inoculated induced anti-IBV antibody 14 days after vaccination. The AVR1/08 strain had broad protective efficacy against QX type Korean nephropathogenic virus (Q43/06 strain), KM91 type Korean nephropathogenic virus (KM91 strain) and Korean respiratory virus (D85/06 strain). In contrast, Massachusetts (Mass) type attenuated vaccine strain H120 showed protection of 37.5 to 50% against these three viruses. Our results indicate that the AVR1/08 strain has potential as an attenuated vaccine effective in controlling IBVs circulating in Korea.

• Pediatric Infection and Vaccine
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• v.16 no.2
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• pp.183-190
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• 2009

Purpose : To evaluate the number and severity of adverse reactions after Japanese Encephalitis (JE) vaccination in children using different vaccines (inactivated vaccine or live attenuated vaccine) and to determine the ability and safety of the vaccines to provide effective immunization for JE. Methods : From August 2006 to February 2007, we conducted a prospective cohort study of the adverse reactions associated with JE immunization in Korea. We investigated common adverse reactions during the 4 days following immunization using telephone collaborations with four public health centers and nine pediatric clinics. Results : The mean age of children receiving the inactivated vaccines and live attenuated vaccines, respectively, were 1.4 y (range: 1 to 8.5) and 1.7 y (range: 1 to 8.3). The number of children that received the inactivated vaccines was 425 (64.6%). A total of 233 (35.4%) received the live attenuated vaccines. Fourteen children (3.3%) had more than one localized adverse event with the inactivated vaccine, and six (2.6%) had more than one event with the live attenuated vaccine (P =0.607). Systemic adverse reactions occurred in 5.2% vs. 8.2%, respectively, of these groups (P =0.131). Fever was more common in the live attenuated vaccine group than in the inactivated vaccine group on the day of vaccination (P =0.026). Conclusions : The rate of adverse events in our study was even lower than that previously reported. No significant difference in outcomes between inactivated vaccine and live attenuated vaccine was found in JE-immunized children. Fever was more common in the live attenuated vaccine group than in the inactivated vaccine group on the day of vaccination.