• Journal of Life Science
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• v.19 no.9
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• pp.1304-1308
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• 2009

To investigate the infection patterns of porcine epidemic diarrhea virus (PEDV) in Korean pig farms, a total of 4,768 swine sera samples from 159 pig farms were taken twice, in June (n=82) and October (n=77) in 2007. In each farm selected for the survey, 10 samples from breeding pigs and 4 from each of the 5 age groups (30, 60, 90, 120, and 150 days) were taken, and all serum samples were tested for PEDV by the serum neutralization test. The overall seroprevalence was 62.6% (2,983/4,768), with the highest prevalence in breeding pigs (93.5%, 1,485/1,589). The prevalence showed an increasing trend with increasing age (30.8, 27.2, 44.7, 61.6, and 71.2% respectively in the 30, 60, 90, 120, and 150 days age groups) (p<0.0001 for $x^2$ trend test). The association between age and PEDV prevalence was similar in both surveys, indicating that the infection of PEDV seemed to be occurring repeatedly in the farms surveyed. This inference could also be explained by the fact that prevalence in sows was very high despite low vaccination coverage, as they are continuously exposed to PEDV in potentially infected farms for a longer period. Based on the neutralizing antibody levels in sows and growing pigs, the majority of farms (91.8%, n=146 farms) were endemically infected with PEDV, and most of pigs seemed to be intensively infected with PEDV at around early growth (41.8%) and weaning (31.5%). On the other hand, serum neutralizing antibodies were not detected in pigs older than 30 days of age in farms classified as having no PEDV infection (n=13 farms), indicating the level of maternal antibody against PEDV is decreased on a non-detectable level before the piglet is 60 days old in the field situation. The results indicated that most farms surveyed in 2007 were affected with endemic PEDV infection. Therefore, a national monitoring and control program for the endemic type PEDV infection needs further attention.

• Infection and chemotherapy
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• v.50 no.4
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• pp.328-339
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• 2018

Background: Pneumococcal disease is a major cause of morbidity and mortality worldwide, especially in patients with comorbidities and advanced age. This study evaluated trends in epidemiology of adult pneumococcal disease in Crete, Greece, by identifying serotype distribution and antimicrobial resistance of consecutive Streptococcus pneumoniae strains isolated from adults during an 8-year time period (2009-2016) and the indirect effect of the infant pneumococcal higher-valent conjugate vaccines 10-valent pneumococcal conjugate vaccine (PCV10) and 13-valent pneumococcal conjugate vaccine (PCV13). Materials and Methods: Antimicrobial susceptibility was performed by E-test and serotyping by Quellung reaction. Multidrug resistance (MDR) was defined as non-susceptibility to penicillin (PNSP) combined with resistance to ${\geq}2$ non-${\beta}$-lactam antimicrobials. Results: A total of 135 S. pneumoniae strains were isolated from adults during the study period. Twenty-one serotypes were identified with 17F, 15A, 3, 19A, and 11A, being the most common. The coverage rates of PCV10, and PCV13 were 17.8% and 37.8%, respectively. PCV13 serotypes decreased significantly from 68.4% in 2009 to 8.3% in 2016 (P = 0.002). The most important emerging non-PCV13 serotypes were 17F, 15A, and 11A, with 15A being strongly associated with antimicrobial resistance and MDR. Among all study isolates, penicillin-resistant and MDR strains represented 7.4% and 14.1%, respectively. Predominant PNSP serotypes were 19A (21.7%), 11A (17.4%), and 15A (17.4%). Erythromycin, clindamycin, tetracycline, trimethoprim-sulfamethoxazole, and levofloxacin resistant rates were 30.4%, 15.6%, 16.3%, 16.3%, and 1.5%, respectively. Conclusion: Although pneumococcal disease continues to be a health burden in adults in Crete, our study reveals a herd protection effect of the infant pneumococcal higher-valent conjugate vaccination. Surveillance of changes in serotype distribution and antimicrobial resistance among pneumococcal isolates are necessary to guide optimal prevention and treatment strategies.

• Pediatric Infection and Vaccine
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• v.22 no.2
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• pp.63-68
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• 2015

Purpose: This study analyzed a small outbreak of measles at a single hospital located in northern Gyeonggi-do in 2013. Methods: We reviewed the medical records of measles patients at The Catholic University of Korea Uijeongbu St. Mary's Hospital from August to October, 2013. Results: Fifteen children were confirmed to have measles by RT-PCR and serum IgM test; 1 neonate, 11 infants, and 3 toddlers. None of the patients had received Measles-Mumps-Rubella vaccination. All patients showed B3 type in viral genotyping. Nine children (60%) had been exposed to measles during treatment for other diseases in the pediatric ward. Incubation period was between 8 and 15 days. Fever started at a median 10 days after exposure and persisted for a median of 8 days. Rash showed at a median 13 days after exposure. Respiratory complications were observed in 40% of patients. Diarrhea developed in 53% of patients. Conclusion: Although measles has been well-controlled due to the high rate of vaccination coverage, it is possible to have an outbreak at any given time, especially in infants. We must learn from this outbreak, and remain fully aware of the possibility of reemergence and provide proper management, including vaccination or immune globulin administration, to infants exposed to measles. Reevaluation of serum IgG titer of neonates, infants, and pregnant women may be the first step to prevent further outbreaks.

• Pediatric Infection and Vaccine
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• v.18 no.2
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• pp.124-134
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• 2011

Purpose : We have tried to search all concerning data on the policies of hepatitis B vaccination or surveillance of medical equipments that can transmit blood mediated diseases, including disposable syringe, in Republic of Korea, to propose references to other medical professionals. Methods : Data from domestic journals, government websites, computerized newspapers, etc. were reviewed. The data were arranged into four categories (governmental policies on hepatitis B control, hepatitis B mass immunization program in school, using process of hepatitis B vaccine, and policies on medical equipments surveillance, including disposable syringes, which is considered as source of blood mediated infection), and the periodic changes on each subjects in policies were reviewed. Results : Due to growing social concerns on hepatitis B in early 1980s, swift introduction and production of hepatitis B vaccine was made. After establishment of "5 year project for eradication of hepatitis B" in late 1983, number of vaccinated population jumped up to 6 million within 2 years (1984-85). However, since the immunization targets were mainly adult, not infant, this project was annulled in late 1985. Following this project, hepatitis B mass immunization program in school was carried out. In year 1995, hepatitis B vaccine was included in national immunization program. The use of disposable syringe was recommended from year 1980 but legislated in year 1985, finally. Conclusion : The mainstay in controlling hepatitis B in Republic of Korea was coordination of prompt introduction of vaccine, mass immunization, high vaccination coverage rate, or use of disposable syringes. However, since there is lack of official data available, it is urgent to arrange and computerize all government data related to infectious diseases.

• Proceedings of the KAIS Fall Conference
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• 2010.11b
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• pp.885-888
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• 2010

현재 우리나라는 보건소 중심의 예방접종등록사업을 진행 중에 있다. 2004년부터 시작된 이 사업은 현재는 전국민을 대상으로 실시하고 있다. 예방접종등록사업은 피접종자들은 대체적으로 예방접종에 대한 적절한 시기를 판단할 수 있는 정보가 부족하기 때문에 예방접종과 관련된 정보들을 국가나 사회에서 적시에 피접종자들에게 제공해 줄 수 있다. 따라서 이에 대한 확인이 등록에 앞서 그 정확성을 확인 필요가 있다. 예방접종등록사업의 가장 기본적인 사업으로 진행된 것은 예방접종 수첩의 제공과 그 관리를 통한 예방접종 사업으로 지속적으로 전개되어 왔으며, 일반 국민과 개원의사들에서도 대중적으로 보급되어 있다. 국가 예방접종률의 산출 그리고 취학 어린이 예방접종력 증명서 제출 제도를 위하여 예방접종 수첩을 활용하는 방법이 현실적으로 유용할 수 있다. 따라서 예방접종 수첩의 예방접종력 정확성을 확인할 필요가 있다. 지역조사에서 접종기관으로 확인된 민간 의료기관 365곳 가운데 의료기관 이전 및 폐업으로 반송된 경우가 4건(1.1%)이었으며, 응답한 경우는 129곳으로 응답률은 35.3%였다. 조사된 의료기관 전체를 대상으로 확인된 1,201건에 대한 BCG 접종여부의 정확도는 69.5%였다. B형 간염의 정확도는 1차가 41.3%로 낮았으며, 2차와 3차는 각각 76.6%, 79.7%였다. DTaP의 정확도는 약 80%였으며, 정확도가 제일 높은 것은 DTaP 3차로 82.5%였으나 다른 것과 가장 낮은 정확도와 2% 정도 밖에 차이가 나지 않았다. 폴리오의 정확도는 약 80%였다. MMR의 정확도는 83.2%였다. 일본뇌염의 경우 약 80.0%였으며, 수두의 정확도는 74.9%로 다른 질병과 비교하여 낮은 수치를 보였다. 조사된 의료기관을 전체로 한 기타예방접종별 예방접종수첩의 접종여부의 정확도는 인플루엔자는 정확도는 74.1%였으며, 뇌수막염은 72.7%의 정확도를 보였다. A형 간염 1차의 정확도79.5%였으며, 폐렴구균 1차의 경우 73.2%로 나타났다. 국가필수예방접종별 예방접종수첩의 접종일자에 대한 정확도는 BCG 80.1%로 확인되었고, B형 간염 1차 89.7% 2차는 82.1% 3차는 79%로 B형 간염 중 가장 낮은 정확도를 보였다. DTaP는 1차와 2차는 약 87% 3차는 85.1% 4차는 83.5%로 확인이 되었다. 폴리오는 1차가88.1%로 가장 높은 정확도를 보였고 그 다음으로 2차가 86.2%, 3차가 84.8%로 확인되었다. MMR의 정확도는 84%였으며, 일본뇌염 1차의 정확도는 83.1%로 나타났다. 수두의 접종일자 정확도는 83.7% 이고, 인플루엔자의 정확도는 55.3%로 상대적으로 낮은 수치를 보였다. 기타예방접종별 접종일자 정확도의 조사 결과 뇌수막염 1차과 폐렴구균 1차는 약 90%로 상대적으로 높은 정확도를 보였고, A형 간염 1차는 88.4%의 정확도를 보였다.

• Journal of Life Science
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• v.28 no.4
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• pp.496-507
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• 2018

Immunization has been performed for centuries and is generally accepted as a sustainable method of controlling bacteria, viruses, and mediated and infectious diseases. Despite many studies having been performed on animal subjects to demonstrate the importance of toxin immunity, the use of toxoid vaccines in humans and animals has been limited for a long time. Recently, the development of the toxoid antigen delivery system has been facilitated using novel nano-medicinal technology. The micro/nano-carrier has been used to improve vaccination coverage as well as reduce vaccine costs. A micro/nano-carrier is a micro/nano-sized material that delivers immune cargo, including recombinant or peptide toxoid antigens. These toxoid antigens are either encapsulated in the interior or displayed on the surface of micro/nano-carriers as a way to protect them from the cellular machinery. In particular, the combination of toxoid antigens and micro/nano-carriers can induce phagocytosis through the specific interactions between GCs and macrophages; thus, the toxoid antigens can be delivered easily into the macrophages. This paper reviews recent achievements of micro/nano-carriers in the field of vaccine delivery systems such as microbial ghost cells (GCs, Bacterial ghost cells and Yeast ghost cells), gene-manipulated outer membrane vesicles (OMVs) and biocompatible, polymer-based nanoparticles (NPs, NP-Carrier and NP-Cage). Finally, this review shows various aspects in terms of the hosts' immune responses.

• Pediatric Infection and Vaccine
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• v.6 no.2
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• pp.245-252
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• 1999

Purpose : The aim of this study is to determine the age-specific seropositivity and the level of measles specific IgG in adults and to evaluate herd immunity to measles in Korea, the measles specific IgG were measured from the sera of adults over ages of 20 in Korea. Methods : 156 sera were collected from 156 out-patients over ages 20, who had visited clinical laboratory from June to July in 1997 at Korea University Ansan Hospital. The histories of natural measles or vaccination were not undertaken. Measles specific IgG titers were measured using ELISA method($SIA^{TM}$ Measles IgG Kit Co. St. Louis. Mo). Results : The results obtained from this study were as follows. 1) The seropositivity of measles specific IgG in adults was 94.9%. And there were no significant differences in their age and gender. 2) The mean measles-specific IgG titer was $238{\pm}84AU/mL$. And there were no significant differences in age and gender, except significant lower in 4th decades than other age groups. And there were no significant correlations between age and measles specific IgG level. Conclusion : In conclusion, a seropositivity of in adults was 94.9% which was higher than that of adolescents(91.2% in previous study), and antibody level was similar with adolescents. The herd immunity of the adults were considered to enough for protecting the transmission of measles in the community. For the eradication of measles in Korea, more efforts will be required to increase the vaccine coverage rate in children and adolescents.