• Journal of Preventive Medicine and Public Health
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• v.38 no.4
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• pp.386-390
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• 2005

Influenza A viruses periodicall y cause worldwide epidemics, or pandemics, with high rates of illness and death. A pandemic can occur at any time, with the potential to cause serious illness, death and social and economic disruption throughout the world. Historic evidence suggests that pandemics occurred three to four times per century. In the last century there were three influenza pandemics. The circumstances still exist for a new influenza virus with pandemic potential to emerge an d spread. The unpredictability of the timing of the next pandemic is underlined by the occurrence of several large outbreaks of highly pathogenic avian influenza since the early 1980s. In 1999, the World Health Organization published the Influenza pandemic plan. The role of WHO and guidelines for national and regional planning. And in 2005, WHO revised the global influenza preparedness plan for new national measures before and during pandemics. This document outlines briefly the Korean Centers for Disease Control's plan for responding to an influenza pandemic. According to the new pandemic phases of WHO, we set up the 4 national levels of preparedness and made guidelines for preventing and control the epidemics in each phase. And also we described the future plans to antiviral stockpiles and pandemic vaccine development.

• Tuberculosis and Respiratory Diseases
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• v.79 no.2
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• pp.70-73
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• 2016

In late March of 2009, an outbreak of influenza in Mexico, was eventually identified as H1N1 influenza A. In June 2009, the World Health Organization raised a pandemic alert to the highest level. More than 214 countries have reported confirmed cases of pandemic H1N1 influenza A. In Korea, the first case of pandemic influenza A/H1N1 infection was reported on May 2, 2009. Between May 2009 and August 2010, 750,000 cases of pandemic influenza A/H1N1 were confirmed by laboratory test. The H1N1-related death toll was estimated to reach 252 individuals. Almost one billion cases of influenza occurs globally every year, resulting in 300,000 to 500,000 deaths. Influenza vaccination induces virus-neutralizing antibodies, mainly against hemagglutinin, which provide protection from invading virus. New quadrivalent inactivated influenza vaccine generates similar immune responses against the three influenza strains contained in two types of trivalent vaccines and superior responses against the additional B strain.

• Korean Journal of Clinical Laboratory Science
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• v.42 no.1
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• pp.1-15
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• 2010

Swine influenza virus (SIV) or swine-origin influenza virus (S-OIV) is endemic in swine, and classified into influenza A and influenza C but not influenza B. Swine influenza A includes H1N1, H1N2, H3N1, H3N2 and H2N3 subtypes. Infection of SIV occurs in only swine and that of S-OIV is rare in human. What human can be infected with S-OIV is called as zoonotic swine flu. Pandemic 2009 swine influenza H1N1 virus (2009 H1N1) was emerged in Mexico, America and Canada and spread worldwide. The triple-reassortant H1N1 resulting from antigenic drift was contained with HA, NA and PB1 of human or swine influenza virus, PB2 and PA polymerase of avian influenza virus, and M, NP and NS of swine influenza virus, The 2009 H1N1 enables to transmit to human and swine. The symptoms and signs in human infected with 2009 H1N1 virus are fever, cough and sore throat, pneumonia as well as diarrhea and vomiting. Co-infection with other viruses and bacteria such as Streptococcus pneumoniae can occur high mortality in high-risk population. 2009 H1N1 virus was easily differentiated from seasonal flu by real time RT-PCR which contributed rapid and confirmed diagnosis. The 2009 H1N1 virus was treated with NA inhibitors such as oseltamivir (Tamiflu) and zanamivir (Relenza) but not with adamantanes such as amantadine and rimantadine. Evolution of influenza virus has continued in various hosts. Development of a more effective vaccine against influenza prototypes is needed to protect new influenza infection such as H5 and H7 subtypes to infect to multi-organ and cause high pathogenicity.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.149-150
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• 2002

Despite various efforts on improving vaccines and antivirals, influenza epidemics continue to afflict many people, causing widespread morbidity and mortality in the young and the elderly. Since the discovery of the unusual 'cap-stealing'mechanism of transcription, significant advances were made on molecular aspects of influenza gene regulation. This provides new insights for developing new antiviral compounds. Reverse genetic technologies have also been advanced for generating recombinant chimeric viruses suitable for designing live vaccine. (omitted)

• Journal of Microbiology and Biotechnology
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• v.29 no.8
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• pp.1184-1192
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• 2019

The influenza A virus is a highly infectious respiratory pathogen that sickens many people with respiratory disease annually. To prevent outbreaks of this viral infection, an understanding of the characteristics of virus-host interaction and development of an anti-viral agent is urgently needed. The influenza A virus can infect mammalian species including humans, pigs, horses and seals. Furthermore, this virus can switch hosts and form a novel lineage. This so-called zoonotic infection provides an opportunity for virus adaptation to the new host and leads to pandemics. Most influenza A viruses express proteins that antagonize the antiviral defense of the host cell. The non-structural protein 1 (NS1) of the influenza A virus is the most important viral regulatory factor controlling cellular processes to modulate host cell gene expression and double-stranded RNA (dsRNA)-mediated antiviral response. This review focuses on the influenza A virus NS1 protein and outlines current issues including the life cycle of the influenza A virus, structural characterization of the influenza A virus NS1, interaction between NS1 and host immune response factor, and design of inhibitors resistant to the influenza A virus.

• Tuberculosis and Respiratory Diseases
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• v.70 no.4
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• pp.285-292
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• 2011

After an outbreak of H1N1 influenza A virus infection in Mexico in late March 2009, the World Health Organization raised its pandemic alert level to phase 6, and to the highest level in June 2009. The pandemic H1N1/A influenza was caused by an H1N1 influenza A virus that represents a quadruple reassortment of two swine strains, one human strain, and one avian strain of influenza. After the first case report of H1N1/A infection in early May 2009, South Korea was overwhelmed by this new kind of influenza H1N1/A pandemic, which resulted in a total of 700,000 formally reported cases and 252 deaths. In this article, clinical characteristics of victims of H1N1/A influenza infection, especially those who developed pneumonia and those who were cared for in the intensive care unit, are described. In addition, guidelines for the treatment of H1N1/A influenza virus infection victims in the ICU, which was suggested by the Korean Society of Critical Care Medicine, are introduced.

• Journal of Preventive Medicine and Public Health
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• v.38 no.4
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• pp.373-378
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• 2005

Influenza virus has a unique characteristics of annual epidemics of acute respiratory disease with attack rate of 10%-30% of the population. It is also the classical emerging infectious disease causing global pandemics when new antigenic shift occur. This antigenic shift is the key to its ability to evoke periodic pandemics, and it has caused at least 3 pandemics in 20th century. I reviewed these 3 pandemics in their natural courses and the epidemiology of the recent emerging influenza A viruses, especially the H5 and H7 subtypes. I descr ibed the epidemics of these vi ruses in human population and why we should be prepared to these viruses.

• Journal of Preventive Medicine and Public Health
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• v.44 no.4
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• pp.141-148
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• 2011

Annual epidemics of seasonal influenza occur during autumn and winter in temperate regions and have imposed substantial public health and economic burdens. At the global level, these epidemics cause about 3-5 million severe cases of illness and about 0.25-0.5 million deaths each year. Although annual vaccination is the most effective way to prevent the disease and its severe outcomes, influenza vaccination coverage rates have been at suboptimal levels in many countries. For instance, the coverage rates among the elderly in 20 developed nations in 2008 ranged from 21% to 78% (median 65%). In the U.S., influenza vaccination levels among elderly population appeared to reach a "plateau" of about 70% after the late 1990s, and levels among child populations have remained at less than 50%. In addition, disparities in the coverage rates across subpopulations within a country present another important public health issue. New approaches are needed for countries striving both to improve their overall coverage rates and to eliminate disparities. This review article aims to describe a broad conceptual framework of vaccination, and to illustrate four potential determinants of influenza vaccination based on empirical analyses of U.S. nationally representative populations. These determinants include the ongoing influenza epidemic level, mass media reporting on influenza-related topics, reimbursement rate for providers to administer influenza vaccination, and vaccine supply. It additionally proposes specific policy implications, derived from these empirical analyses, to improve the influenza vaccination coverage rate and associated disparities in the U.S., which could be generalizable to other countries.

• Clinical and Experimental Pediatrics
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• v.56 no.4
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• pp.165-175
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• 2013

Purpose: There was a global increase in the prevalence of oseltamivir-resistant influenza viruses during the 2007-2008 influenza season. This study was conducted to investigate the occurrence and characteristics of oseltamivir-resistant influenza viruses during the 2007-2008 and 2008-2009 influenza seasons among patients who were treated with oseltamivir (group A) and those that did not receive oseltamivir (group B). Methods: A prospective study was conducted on 321 pediatric patients who were hospitalized because of influenza during the 2007-2008 and 2008-2009 influenza seasons. Drug resistance tests were conducted on influenza viruses isolated from 91 patients. Results: There was no significant difference between the clinical characteristics of groups A and B during both seasons. Influenza A/H1N1, isolated from both groups A and B during the 2007-2008 and 2008-2009 periods, was not resistant to zanamivir. However, phenotypic analysis of the virus revealed a high oseltamivir $IC_{50}$ range and that H275Y substitution of the neuraminidase (NA) gene and partial variation of the hemagglutinin (HA) gene did not affect its antigenicity to the HA vaccine even though group A had a shorter hospitalization duration and fewer lower respiratory tract complications than group B. In addition, there was no significant difference in the clinical manifestations between oseltamivir-susceptible and oseltamivir-resistant strains of influenza A/H1N1. Conclusion: Establishment of guidelines to efficiently treat influenza with oseltamivir, a commonly used drug for treating influenza in Korean pediatric patients, and a treatment strategy with a new therapeutic agent is required.

• Journal of Microbiology and Biotechnology
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• v.28 no.5
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• pp.809-815
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• 2018

Influenza, which is a highly contagious disease caused by the influenza A virus, continues to be a major health concern worldwide. Although the accurate and early diagnosis of influenza virus infection is important for controlling the spread of this disease and rapidly initiating antiviral therapy, the current influenza diagnostic kits are limited by their low sensitivity. In this study, we developed several new influenza nucleoprotein (NP)-specific monoclonal antibodies (mAbs) and compared their sensitivity and specificity of those with commercially available anti-NP mAbs. Three mAbs, designated M24.11, M34.3, and M34.33, exhibited higher reactivities to recombinant NPs and A/Puerto Rico/8/1934 (H1N1) viral lysates compared with the commercial mAbs, as assessed using enzyme-linked immunosorbent assays. M34.3 and M34.33 showed higher reactivities with A/California/04/09 (pandemic H1N1) and A/Philippines/2/82 (H3N2) viral lysates than the commercial mAbs. In contrast, M24.11 had marked reactivity with H3N2 but not with pandemic H1N1. Immunofluorescent confocal microscopy showed that the three mAbs effectively detected the presence of influenza virus in lung tissues of mice infected with A/Puerto Rico/8/1934. These results indicate that the newly developed M34.3 and M34.33 mAbs could be useful for the development of influenza diagnostics.