• Journal of Microbiology and Biotechnology
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• v.27 no.9
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• pp.1701-1710
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• 2017

Classical swine fever virus (CSFV) is the etiologic agent of classical swine fever, a highly contagious disease that causes significant economic losses to the swine industry. The lapinized C-strain, a widely used vaccine strain against CSFV, has low growth efficiency in cell culture, which limits the productivity in the vaccine industry. In this study, a recombinant virus derived from C-strain was constructed and subjected to continuous passaging in PK-15 cells with the goal of acquiring a high progeny virus yield. A cell-adapted virus variant, RecCpp80, had nearly 1,000-fold higher titer than its parent C-strain but lost the ability to induce fever in rabbits. Sequence analysis of cell-adapted RecC variants indicated that at least six nucleotide changes were fixed in RecCpp80. Further adaption of RecCpp80 variant in swine testicle cells led to a higher virus yield without additional mutations. Introduction of each of these residues into the wild-type RecC backbone showed that one mutation, M979R (T3310G), located in the C-terminal region of E2 might be closely related to the cell-adapted phenotype. Rabbit inoculation revealed that $RecCpp40_{+10}$ failed to induce fever in rabbits, whereas $RecCpp80_{+10}$ caused a fever response similar to the commercial C-strain vaccine. In conclusion, the C-strain can be adapted to cell culture by introducing specific mutations in its E2 protein. The mutations in RecCpp80 that led to the loss of fever response in rabbits require further investigation. Continuous passaging of the C-strain-based recombinant viruses in PK-15 cells could enhance its in vitro adaption. The non-synonymous mutations at 3310 and 3531 might play major roles in the enhanced capacity of general virus reproduction. Such findings may help design a modified C-strain for improved productivity of commercial vaccines at reduced production cost.

• 대한예방의학회:학술대회논문집
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• 2000.10a
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• pp.89-89
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• 2000

• Kidney Research and Clinical Practice
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• v.37 no.4
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• pp.366-372
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• 2018

Background: An inactivated Hantaan virus vaccine (iHV) has been broadly used as a preventive strategy for hemorrhagic fever with renal syndrome (HFRS) by the South Korean Army. After the vaccination program was initiated, the overall incidence of HFRS cases was reduced in the military population. While there are about 400 HFRS cases annually, few studies have demonstrated the efficacy of the iHV in field settings. Therefore, this study aimed to evaluate the iHV efficacy on HFRS severity. Methods: From 2009 to 2017, HFRS cases were collected in South Korean Army hospitals along with patients' vaccination history. HFRS patients were classified retrospectively into two groups according to vaccination records: no history of iHV vaccination and valid vaccination. Vaccine efficacy on the severity of acute kidney injury (AKI) stage and dialysis events were investigated. Results: The effects of the iHV on renal injury severity in between 18 valid vaccinated and 110 non-vaccinated patients were respectively evaluated. In the valid vaccination group, six of the 18 HFRS patients (33.3%) had stage 3 AKI, compared to 60 of the 110 (54.5%) patients in the non-vaccination group. The iHV efficacy against disease progression ($VE_p$) was 58.1% (95% confidence interval, 31.3% to 88.0%). Conclusion: The iHV efficacy against the progression of HFRS failed to demonstrate statistically significant protection. However, different severity profiles were observed between the iHV and non-vaccination groups. Additional studies with larger populations are needed to demonstrate the effectiveness of the iHV in patients with HFRS.

• 대한예방의학회:학술대회논문집
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• 2001.10a
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• pp.280-280
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• 2001

• 대한예방의학회:학술대회논문집
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• 2001.10a
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• pp.135-135
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• 2001

• Journal of Preventive Medicine and Public Health
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• v.56 no.3
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• pp.221-230
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• 2023

Objectives: The second wave of coronavirus disease 2019 (COVID-19) cases in Indonesia, during which the Delta variant predominated, took place after a vaccination program had been initiated in the country. This study was conducted to assess the impact of COVID-19 vaccination on unfavorable clinical outcomes including hospitalization, severe COVID-19, intensive care unit (ICU) admission, and death using a real-world model. Methods: This single-center retrospective cohort study involved patients with COVID-19 aged ≥18 years who presented to the COVID-19 emergency room at a secondary referral teaching hospital between June 1, 2021 and August 31, 2021. We used a binary logistic regression model to assess the effect of COVID-19 vaccination on unfavorable clinical outcomes, with age, sex, and comorbidities as confounding variables. Results: A total of 716 patients were included, 32.1% of whom were vaccinated. The elderly participants (≥65 years) had the lowest vaccine coverage among age groups. Vaccination had an effectiveness of 50% (95% confidence interval [CI], 25 to 66) for preventing hospitalization, 97% (95% CI, 77 to 99) for preventing severe COVID-19, 95% (95% CI, 56 to 99) for preventing ICU admission, and 90% (95% CI, 22 to 99) for preventing death. Interestingly, patients with type 2 diabetes had a 2-fold to 4-fold elevated risk of unfavorable outcomes. Conclusions: Among adults, COVID-19 vaccination has a moderate preventive impact on hospitalization but a high preventive impact on severe COVID-19, ICU admission, and death. The authors suggest that relevant parties increase COVID-19 vaccination coverage, especially in the elderly population.

• Journal of Preventive Medicine and Public Health
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• v.40 no.2
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• pp.185-190
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• 2007

Objectives : Since the first human infection from avian influenza was reported in Hong Kong in 1997, many Asian countries have confirmed outbreaks of highly pathogenic H5N1 avian influenza viruses. In addition to Asian countries, the EU authorities also held an urgent meeting in February 2006 at which it was agreed that Europe could also become the next target for H5N1 avian influenza in the near future. In this paper, we provide the general and applicable information on the avian influenza in the bioinformatics field to assist future studies in preventive medicine. Methods : We introduced some up-to-date analytical tools in bioinformatics research, and discussed the current trends of avian influenza outbreaks. Among the bioinformatics methods, we focused our interests on two topics: pattern analysis using the secondary database of avian influenza, and structural analysis using the molecular dynamics simulations in vaccine design. Results : Use of the public genome databases available in the bioinformatics field enabled intensive analysis of the genetic patterns. Moreover, molecular dynamic simulations have also undergone remarkable development on the basis of the high performance supercomputing infrastructure these days. Conclusions : The bioinformatics techniques we introduced in this study may be useful in preventive medicine, especially in vaccine and drug discovery.

• Journal of Preventive Medicine and Public Health
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• v.51 no.4
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• pp.173-180
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• 2018

Objectives: Immunization is considered one of the most successful and cost-effective public health interventions protecting communities from preventable infectious diseases. The Korean government set up a dedicated workforce for national immunization in 2003, and since then has made strides in improving vaccination coverage across the nation. However, some groups remain relatively vulnerable and require intervention, and it is necessary to address unmet needs to prevent outbreaks of communicable diseases. This study was conducted to characterize persistent challenges to vaccination. Methods: The study adopted a qualitative method in accordance with the Consolidated Criteria for Reporting Qualitative Research checklist. Three focus group interviews were conducted with 15 professionals in charge of vaccination-related duties. The interviews were conducted according to a semi-structured guideline, and thematic analysis was carried out. Data saturation was confirmed when the researchers agreed that no more new codes could be found. Results: A total of 4 main topics and 11 subtopics were introduced regarding barriers to vaccination. The main topics were vaccine hesitancy, personal circumstances, lack of information, and misclassification. Among them, vaccine hesitancy was confirmed to be the most significant factor impeding vaccination. It was also found that the factors hindering vaccination had changed over time and disproportionately affected certain groups. Conclusions: The study identified ongoing unmet needs and barriers to vaccination despite the accomplishments of the National Immunization Program. The results have implications for establishing tailored interventions that target context- and group-specific barriers to improve timely and complete vaccination coverage.

• Journal of Preventive Medicine and Public Health
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• v.41 no.3
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• pp.153-158
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• 2008

Objectives : This study describes a plan that was designed to prevent a measles outbreak that showed a changed outbreak pattern. This study is based on the epidemiological investigation of a measles outbreak in a preschool in Incheon, Korea, 2006. Methods : The subjects were 152 students at a preschool where a measles outbreak occurred. A questionnaire survey was conducted and serological testing for measles-specific IgM was preformed. Results : Of the fifteen confirmed, identified cases, eleven patients had been vaccinated with one dose, one patient had received two doses and three patients were unvaccinated. The three unvaccinated cases consisted of one 5-year-old child, one 3-year-old child and one 16-month-old infant. For the cases with one dose of the vaccination, there were 11 cases, which consisted of six 5-year-old children, two 4-year-old children, two 3-year-old children and one 2-year-old child. The case with two doses of the vaccination was one 4-year-old child. The attack rate of measles was 100% in the 0-dose group, 11.2% in the 1-dose group and 2.0% in the 2-dose group. The vaccine's efficacy was 88.8% in the 1-dose group and 98.0% in the 2-dose group. The vaccine effectiveness for the 2-dose group was higher than that of the 1-dose group. Conclusions : High coverage with a 2-dose vaccination should be maintained, and the vaccination should be given at the suitable time to prevent a measles outbreak with a changed outbreak pattern.

• Journal of Preventive Medicine and Public Health
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• v.56 no.2
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• pp.172-179
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• 2023

Objectives: Vaccination is an important intervention for preventing disease and reducing disease severity. Universal vaccination programs have significantly reduced the incidence of many dangerous diseases among children worldwide. This study investigated the side effects after immunization in infants under 1 year of age in Lorestan Province, western Iran. Methods: This descriptive analytical study included data from all children <1 year old in Lorestan Province, Iran who were vaccinated according to the national schedule in 2020 and had an adverse event following immunization (AEFI). Data were extracted from 1084 forms on age, sex, birth weight, type of birth, AEFI type, vaccine type, and time of vaccination. Descriptive statistics (frequency, percentage) were calculated, and the chi-square test and Fisher exact test were used to assess differences in AEFIs according to the abovelisted variables. Results: The most frequent AEFIs were high fever (n=386, 35.6%), mild local reaction (n=341, 31.5%), and swelling and pain (n=121, 11.2%). The least common AEFIs were encephalitis (n=1, 0.1%), convulsion (n=2, 0.2%), and nodules (n=3, 0.3%). Girls and boys only showed significant differences in mild local reactions (p=0.044) and skin allergies (p=0.002). The incidence of lymphadenitis (p<0.001), severe local reaction (p<0.001), mild local reaction (p=0.007), fainting (p=0.032), swelling and pain (p=0.006), high fever (p=0.005), and nodules (p<0.001) showed significant differences based on age at vaccination. Conclusions: Immunization is a fundamental public health policy for controlling vaccine-preventable infectious diseases. Although vaccines such as the Bacillus Calmette-Guérin vaccine, oral poliovirus vaccine, and pentavalent vaccine are well-researched and reliable, AEFIs are inevitable.