Tae Un Yang

Influenza and Pneumococcal Vaccine Coverage Rates among Patients Admitted to a Teaching Hospital in South Korea

Background Influenza and pneumococcal vaccinations can reduce morbidity and mortality especially in the elderly and patients with chronic medical disease. The purpose of this study was to estimate vaccination coverage of these populations in a hospital setting. Materials and Methods We conducted a cross-sectional, descriptive study involving adult patients admitted to a 1,000-bed teaching hospital on April 15, 2013. We ascertained the information on whether the patient had received influenza vaccination within a year prior to admission or pneumococcal vaccination by interviewing each patient. Results A total of 491 eligible patients aged ≥50 years or with chronic medical illnesses were analyzed. The overall vaccination rate for influenza was 57.2%, and that of pneumococcus was 17.6% among the vaccine-eligible subjects. Influenza/pneumococcal vaccination rates of patients by disease were 62.8%/17.2% for diabetes, 53.3%/15.6% for malignancy, 67.6%/23.5% for chronic pulmonary disease, 66.7%/15.3% for chronic cardiovascular disease, 68.7%/26.9% for chronic renal disease, and 51.2%/18.6% for chronic hepatic disease. Young adult patients with chronic medical conditions were consistently less likely to receive influenza and pneumococcal vaccines irrespective of the underlying disease. Conclusion The influenza and pneumococcal vaccine coverage rates among hospitalized patients were low in South Korea. This was especially the case for young adult patients with chronic medical illnesses.

Successful introduction of an underutilized elderly pneumococcal vaccine in a national immunization program by integrating the pre-existing public health infrastructure

BACKGROUND Although pneumococcal vaccines had been recommended for the elderly population in South Korea for a considerable period of time, the coverage has been well below the optimal level. To increase the vaccination rate with integrating the pre-existing public health infrastructure and governmental funding, the Korean government introduced an elderly pneumococcal vaccination into the national immunization program with a 23-valent pneumococcal polysaccharide vaccine in May 2013. OBJECTIVE The aim of this study was to assess the performance of the program in increasing the vaccine coverage rate and maintaining stable vaccine supply and safe vaccination during the 20 months of the program. METHODS We qualitatively and quantitatively analyzed the process of introducing and the outcomes of the program in terms of the systematic organization, efficiency, and stability at the national level. RESULTS A staggered introduction during the first year utilizing the public sector, with a target coverage of 60%, was implemented based on the public demand for an elderly pneumococcal vaccination, vaccine supply capacity, vaccine delivery capacity, safety, and sustainability. During the 20-month program period, the pneumococcal vaccine coverage rate among the population aged ≥65 years increased from 5.0% to 57.3% without a noticeable vaccine shortage or safety issues. A web-based integrated immunization information system, which includes the immunization registry, vaccine supply chain management, and surveillance of adverse events following immunization, reduced programmatic errors and harmonized the overall performance of the program. CONCLUSION Introduction of an elderly pneumococcal vaccination in the national immunization program based on strong government commitment, meticulous preparation, financial support, and the pre-existing public health infrastructure resulted in an efficient, stable, and sustainable increase in vaccination coverage.

Clinical Manifestations of Influenza A and B in Children and Adults at a Tertiary Hospital in Korea during the 2011–2012 Season

This study aims to evaluate and compare the epidemiological patterns and clinical courses of influenza A and B among children and adults. For this purpose, we retrospectively reviewed the medical records of 809 children and 271 adolescents/adults with laboratory-confirmed influenza between October 2011 and May 2012 at a tertiary-care hospital. Children with influenza B presented with high fever (body temperature >39℃), sputum production, diarrhea, nausea/vomiting, and myalgia more frequently than those with influenza A. Children with influenza B also showed longer intervals from symptom onset to the initiation of antivirals and higher rates of antibiotic prescription and hospitalization than those with influenza A. Adults aged 20-59 years accounted for approximately 16% and 20% of patients with influenza A and B, respectively. Although clinical manifestations and outcomes were similar between adult patients with influenza A and those with influenza B, influenza B may cause substantial disease burden among not only children but also socially active adults aged 20-59 years.

Resurgence of measles in a country of elimination: interim assessment and current control measures in the Republic of Korea in early 2014

Since the beginning of 2014, the Republic of Korea has experienced a resurgence of measles cases. Among the 220 cases confirmed as measles during epidemiological weeks 1-20 (December 29, 2013 to May 17, 2014), 10 imported cases were identified. The predominant genotype was B3, which reflects the circulating measles virus in adjacent countries. Even with the verification of measles elimination in March 2014 by the World Health Organization, recent importation has been related to international travel. Targeted control measures have been implemented in addition to proper isolation and patient care. A vigilant surveillance system and high levels of vaccine coverage should be maintained to sustain the measles elimination status.

Age- and influenza activity-stratified case definitions of influenza-like illness: experience from hospital-based influenza surveillance in South Korea.

Objectives This study aims to identify clinical case definitions of influenza with higher accuracy in patients stratified by age group and influenza activity using hospital-based surveillance system. Methods In seven tertiary hospitals across South Korea during 2011–2012 influenza season, respiratory specimens were obtained from patients presenting an influenza-like illness (ILI), defined as having fever plus at least one of following symptoms: cough, sore throat or rhinorrhea. Influenza was confirmed by reverse transcriptase-polymerase chain reaction. We performed multivariate logistic regression analyses to identify clinical variables with better relation with laboratory-confirmed influenza, and compared the accuracy of combinations. Results Over the study period, we enrolled 1417 patients, of which 647 had laboratory-confirmed influenza. Patients with cough, rhinorrhea, sore throat or headache were more likely to have influenza (p<0.05). The most accurate criterion across the study population was the combination of cough, rhinorrhea, sore throat and headache (sensitivity 71.3%, specificity 60.1% and AUROC 0.66). The combination of rhinorrhea, sore throat and sputum during the peak influenza activity period in the young age group showed higher accuracy than that using the whole population (sensitivity 89.3%, specificity 72.1%, and AUROC 0.81). Conclusions The accuracy of clinical case definitions of influenza differed across age groups and influenza activity periods. Categorizing the entire population into subgroups would improve the detection of influenza patients in the hospital-based surveillance system.

Pulmonary toxocariasis mimicking invasive aspergillosis in a patient with ulcerative colitis.

A 45-year-old-male who had underlying ulcerative colitis and presented with fever and dry cough. Initially, the patient was considered to have invasive aspergillosis due to a positive galactomannan assay. He was treated with amphotericin B followed by voriconazole. Nevertheless, the patient deteriorated clinically and radiographically. The lung biopsy revealed eosinophilic pneumonia, and ELISA for Toxocara antigen was positive, leading to a diagnosis of pulmonary toxocariasis. After a 10-day treatment course with albendazole and adjunctive steroids, the patient recovered completely without any sequelae. Pulmonary toxocariasis may be considered in patients with subacute or chronic pneumonia unresponsive to antibiotic agents, particularly in cases with eosinophilia.

Long-term immunogenicity of the influenza vaccine at reduced intradermal and full intramuscular doses among healthy young adults

Purpose To prepare for vaccine shortages under an influenza pandemic, several antigen-sparing strategies have been investigated. This study was aimed to evaluate the immunogenicity of influenza vaccine at reduced intradermal and full intramuscular dose. Materials and Methods We compared the effect of one-fifth and one-half intradermal doses to the full intramuscular dose on immunogenicity in healthy young adults, using a commercial influenza vaccine. A hemagglutination inhibition assay was used to compare the immunogenicity of the vaccination methods. Results The one-fifth intradermal dose (3 µg hemagglutinin antigen, HA) was given to 30 participants, the one-half intradermal dose (7.5 µg HA) was given to 30, and the full intramuscular dose (15 µg HA) was given to 32. No significant differences among injection routes and dosages were seen for seroprotection rate, seroconversion rate, or geometric mean titer (GMT) fold-increase for A/H1N1, A/H3N2, and B at around 4 weeks from vaccination. Although GMT for influenza B was significantly lower at six months for the one-fifth intradermal vaccination compared to the full-dose intramuscular vaccination (32.8 vs. 63.2, p=0.048), all three groups met the Evaluation of Medicinal Products (EMA) immunogenicity criteria through 1 to 6 months. Conclusion Intradermal administration of a one-fifth dose of influenza vaccine elicited antibody responses comparable to the intradermal one-half dose and a conventional intramuscular vaccination at 1 month post-vaccination. The immunogenicity of the one-fifth intradermal dose was sufficient to meet the requirement for the EMA criteria at six months after influenza vaccination.

Survey on public awareness, attitudes, and barriers for herpes zoster vaccination in South Korea

A cross-sectional study was performed to assess current public awareness of herpes zoster (HZ) and its vaccine, determine the factors that influence peoples intention regarding HZ vaccination, and investigate the barriers for vaccination by changing decisions with sequential questions regarding knowledge, cost, and physicians recommendation in the Department of Infectious Diseases, Korea University Guro Hospital, in South Korea, between August 23 and September 15 of 2013. Among 603 subjects who completed the survey, 85.7% and 43.6% subjects were aware of HZ and HZ vaccination, respectively. Women, younger age group, those with higher income or higher education levels were more likely to be aware of HZ. Overall, 85.8% of subjects aware of HZ were willing to be vaccinated or vaccinate their parents. The main obstacles for the increased acceptance toward vaccination were the high cost and low perceived risk, which decreased acceptance to 60.2%. However, physicians recommendation reversed 69.5% of the refusal to accept HZ vaccine. These results indicate that expanding public education and physicians recommendations are important factors aimed at increasing HZ vaccine coverage rate.

How Can We Identify the Elimination of Infectious Diseases? Experience From an Active Measles Laboratory Surveillance System in the Republic of Korea.

Global efforts have markedly decreased the disease burden of vaccine-preventable diseases. Many countries have made considerable progress toward the elimination of measles. As elimination is approached, the very low incidence achieved by high vaccination coverage has underscored the need for a sensitive and timely surveillance system. In the Republic of Korea, an active laboratory surveillance system (ALSS) was implemented to supplement the existing passive surveillance system in 2006. The ALSS connects 5 major commercial laboratories and the national measles reference laboratory, where referred samples with positive or equivocal results are retested. Annually, from 2009 to 2013, 3714 suspected cases were detected through the ALSS, an expansion of 8- to 57-fold, compared with only the passive surveillance system. The ALSS, with its sensitivity and timeliness, is a reasonable strategy to supplement the existing measles surveillance system and to help identify the elimination of measles.

Psychogenic illness following vaccination: exploratory study of mass vaccination against pandemic influenza A (H1N1) in 2009 in South Korea

Purpose Adverse events during mass vaccination campaigns have had a profoundly negative impact on vaccine coverage rates. The objective of the study was to identify the characteristics of reported psychogenic illness cases following mass vaccination that needed further interventions of the national immunization program. Materials and Methods We collected documents that were submitted to the Korea Centers for Disease Control and Prevention for vaccine injury compensation, and analyzed cases of psychogenic illness following pandemic influenza A (H1N1) vaccination in 2009 which were confirmed by the Korean Advisory Committee on Vaccine Injury Compensation. Results During the 2009-2010 influenza season, 13 million Koreans were vaccinated against pandemic influenza. Of 28 reported psychogenic illness cases following immunization, 25 were vaccinated through school-located mass immunization. Significant numbers of them were female adolescents (68%) or had underlying vulnerable conditions or emotional life stressors (36%). They required lengthy hospitalization (median, 7 days) and high medical costs (median, US