Young June Choe

Comparative estimation of coverage between national immunization program vaccines and non-NIP vaccines in Korea.

This study aimed to describe the differences in vaccination coverage between National Immunization Program (NIP) vaccines and non-NIP vaccines in Korea and to identify factors affecting the difference. Nationwide face-to-face interview-based questionnaire survey among randomly selected 4,374 participants aged 7-83 months was conducted. Vaccination coverage analyzed according to the birth cohorts, geographic areas, and socio-demographic characteristics. We found that NIP vaccines recorded higher primary vaccination coverage compared to non-NIP vaccines (95.9%-100% vs 30.7%-85.4%). The highest rate was Haemophilus influenzae type b (Hib) vaccine (85.4%), which was introduced in 1996, and the lowest rate was rotavirus vaccine (30.7%), which was introduced recently. On multivariate analysis, having a sibling were significantly associated with lower uptake of Hib vaccine, pneumococcal conjugate vaccine (PCV), and rotavirus vaccine; while, older mothers age and attendance to daycare center were significantly associated with lower uptake of PCV and rotavirus vaccine (P < 0.001). We found differences in the vaccine coverage rate between NIP vaccines and non-NIP vaccines; and the data suggests potential disparity in accessing non-NIP vaccines in Korea. Expansion of NIP to include non-NIP vaccines can provide better protection against the diseases through increased coverage.

No association between influenza A(H1N1)pdm09 vaccination and narcolepsy in South Korea: An ecological study

BACKGROUND There is concern about a possible association between influenza A(H1N1)pdm09 vaccination and narcolepsy. In this study, we assessed the incidence and incidence rate of narcolepsy in the South Korean population before and after the implementation of an A(H1N1)pdm09 vaccination campaign to see if vaccination led to a change in the occurrence of narcolepsy. METHODS We conducted an ecological study, comparing incident cases and incidence rates for newly diagnosed narcolepsy case-patients in South Korea, between July 2006 and June 2011. We used data from the Health Insurance Review Agency and Korea Centers for Disease Control and Prevention, which have limited information on case ascertainment. During vaccination campaign period, South Korea used non-adjuvanted and MF59-adjuvanted A(H1N1)pdm09 vaccines. RESULTS Generally, incidence rate was highest in prepandemic period. No trend toward increase in the incidence of narcolepsy after pandemic period was found. Observation of incidence by season did not suggest any time pattern for occurrence of narcolepsy. CONCLUSION No increase in cases or incidence rate for narcolepsy during the A(H1N1)pdm09 vaccination campaign was found in South Korea. Our data do not support the use of MF59-adjuvanted or non-adjuvanted A(H1N1)pdm09 vaccine as a trigger for narcolepsy on a population level.

Guillain―Barré syndrome following receipt of influenza A (H1N1) 2009 monovalent vaccine in Korea with an emphasis on Brighton Collaboration case definition

BACKGROUND In 2009-2010 season, with ongoing of influenza A (H1N1), employment of mass vaccination has generated concerns in issue of adverse events following immunization (AEFI). This study investigates the clinical and laboratory data of reported cases of Guillain-Barré syndrome (GBS) and Fisher syndrome (FS) following receipt of influenza A (H1N1) 2009 monovalent vaccine to the National Vaccine Injury Compensation Program (NVICP) in Korea, with all cases reviewed under case definition developed by Brighton Collaboration GBS Working Group. METHOD Retrospective review of medical records for all suspected cases of GBS ad FS following receipt of influenza A (H1N1) monovalent vaccine reported to NVICP from December 1, 2009, through April 28, 2010 was conducted. Additional analyses were performed for identification of levels of diagnostic certainty according to Brighton Collaboration case definition. RESULT Of 29 reported cases, 22 were confirmed to meet Brighton criteria level 1, 2, or 3 for GBS (21) or FS (1). Of those, 2 (9.1%) met level 1, 9 (40.9%) met level 2, and 11 (50.0%) met level 3. The male to female ratio was 2:0 in cases with level 1, 8:1 in cases with level 2, and 3:8 in cases with level 3. The mean age was older in cases with level 1 (54.0 ± 26.9) than that of cases with level 2 (25.6 ± 22.8), and level 3 (13.6 ± 2.4, P=0.005). The median onset interval was longer in cases with level 1 (16 days) than that of cases that met level 2 (12.44 days), and 3 (1.09 days, P=0.019). CONCLUSION The Brighton case definition was used to improve the quality of AEFI data in Korea, and was applicable in retrospective review of medical records in cases with GBS and FS after influenza A (H1N1) vaccination. These findings suggest that standardized case definition was feasible in clarifying the AEFI data, and to further increase the understanding of possible relationship of influenza vaccine and GBS.

Outbreak of enterotoxigenic Escherichia coli O169 enteritis in schoolchildren associated with consumption of kimchi, Republic of Korea, 2012.

Enterotoxigenic Escherichia coli (ETEC) is now recognized as a common cause of foodborne outbreaks. This study aimed to describe the first ETEC O169 outbreak identified in Korea. In this outbreak, we identified 1642 cases from seven schools. Retrospective cohort studies were performed in two schools; and case-control studies were conducted in five schools. In two schools, radish kimchi was associated with illness; and in five other schools, radish or cabbage kimchi was found to have a higher risk among food items. Adjusted relative risk of kimchi was 5·87-7·21 in schools that underwent cohort studies; and adjusted odds ratio was 4·52-12·37 in schools that underwent case-control studies. ETEC O169 was isolated from 230 affected students, and was indistinguishable from the isolates detected from the kimchi product distributed by company X, a food company that produced and distributed kimchi to all seven schools. In this outbreak, we found that the risk of a kimchi-borne outbreak of ETEC O169 infection is present in Korea. We recommend continued monitoring regarding food safety in Korea, and strengthening surveillance regarding ETEC O169 infection through implementation of active laboratory surveillance to confirm its infection.

National pertussis surveillance in South Korea 1955-2011: epidemiological and clinical trends

BACKGROUND Although there has been substantial progress in controlling pertussis in South Korea, the reported number of pertussis case-patients has gradually been increasing during the last decade. To address this, we summarized the surveillance data on pertussis collected during the period 1955-2011. Detailed epidemiologic and clinical data were determined, primarily using data from recent years. METHODS We analyzed data from the national surveillance system to describe the occurrence of pertussis. The annual numbers of reported pertussis case-patients were identified for the period 1955-2000. For 2001-2009, information including limited demographic characteristics and the date of onset of symptoms were identified. For 2010-2011, detailed epidemiologic and clinical information of reported pertussis case-patients were collected. RESULTS During 1955-2011, the secular trend was characterized by a gradual decrease in the reported number of cases from 1955 to the late 1990s, then a recent increase starting in the early 2000s. In 2009, a large number of reported cases occurred in infants <1 year of age. In 2011, an increase in reported cases among adolescents and adults aged ≥15 years was observed. During 2010-2011, 29.8% of reported cases were not immunized and 11.3% had not been immunized in a timely manner. Of adolescents and adults aged ≥15 years, 91.7% did not have a record of immunization. CONCLUSIONS During 2010-2011, a shift in age group was observed in pertussis case-patients: 33.8% were young infants <3 months of age and 29.0% were adolescents and adults ≥15 years of age. Considering that infants without timely vaccination may be vulnerable to an increased risk of pertussis infection, steps to provide timely vaccination to infants, to provide Tdap vaccination to adolescents and adults, and to enhance surveillance to capture adult pertussis cases should be taken in South Korea.

An adverse event following 2009 H1N1 influenza vaccination: a case of acute disseminated encephalomyelitis

Acute disseminated encephalomyelitis (ADEM) is an inflammatory demyelinating disease of the central nervous system that typically follows an infection or vaccination and has a favorable long-term prognosis. We describe the first reported case of ADEM after vaccination against novel influenza A (H1N1). A previously healthy 34-month-old boy who developed ADEM presented with a seizure and left-sided weakness 5 days after vaccination against novel influenza A (H1N1). Cerebrospinal fluid examination revealed elevated cell counts. T2-weighted images and fluid-attenuated inversion recovery images revealed multiple patchy hyperintense lesions in the frontal and parietal subcortical white matter and the left thalamus. After the administration of intravenous corticosteroid, the patients clinical symptoms improved and he recovered completely without neurologic sequelae.

Serious adverse events following receipt of trivalent inactivated influenza vaccine in Korea, 2003-2010.

BACKGROUND Vaccination is very important for the control and prevention of influenza, yet no vaccine is perfectly safe. Little is known, however, about influenza vaccination-associated serious adverse events following immunization (AEFI). This study aimed to identify background information on influenza vaccination-related serious AEFI in Korea. METHODS Retrospective review of data from Korea National Vaccine Injury Compensation Program from 2003 to 2010. RESULTS Distribution of approximately 75 million doses of influenza vaccine by end of 2010 gave rise to 42 potentially serious AEFI. In all, nine Guillain-Barré syndrome, eighteen other neurologic events, eight local events, and seven miscellaneous events were included. 62% of these events were identified to have unlike causal association with the vaccine. The reporting rate of serious AEFI ranged from 0.006 to 0.07 cases per 100,000 distributed doses of the vaccine. CONCLUSION GBS was the most common influenza vaccination-related serious AEFI. Enhancing post-vaccination GBS surveillance may increase public confidence in future routine and pandemic influenza vaccination.

Economic analysis of measles elimination program in the Republic of Korea, 2001: A cost benefit analysis study

BACKGROUND In this study, we modeled the cost benefit analysis for three different measles vaccination strategies based upon three different measles-containing vaccines in Korea, 2001. We employed an economic analysis model using vaccination coverage data and population-based measles surveillance data, along with available estimates of the costs for the different strategies. In addition, we have included analysis on benefit of reduction of complication by mumps and rubella. METHODS We evaluated four different strategies: strategy 1, keep-up program with a second dose measles-mumps-rubella (MMR) vaccine at 4-6 years without catch-up campaign; strategy 2, additional catch-up campaign with measles (M) vaccine; strategy 3, catch-up campaign with measles-rubella (MR) vaccine; and strategy 4, catch-up campaign with MMR vaccine. The cost of vaccination included cost for vaccines, vaccination practices and other administrative expenses. The direct benefit of estimated using data from National Health Insurance Company, a government-operated system that reimburses all medical costs spent on designated illness in Korea. RESULTS With the routine one-dose MMR vaccination program, we estimated a baseline of 178,560 measles cases over the 20 years; when the catch-up campaign with M, MR or MMR vaccines was conducted, we estimated the measles cases would decrease to 5936 cases. Among all strategies, the two-dose MMR keep-up program with MR catch-up campaign showed the highest benefit-cost ratio of 1.27 with a net benefit of 51.6 billion KRW. CONCLUSION Across different vaccination strategies, our finding suggest that MR catch-up campaign in conjunction with two-dose MMR keep-up program was the most appropriate option in terms of economic costs and public health effects associated with measles elimination strategy in Korea.

Novel CFTR Mutations in a Korean Infant with Cystic Fibrosis and Pancreatic Insufficiency

Cystic fibrosis (CF) is an autosomal recessive disease that is very rare in Asians: only a few cases have been reported in Korea. We treated a female infant with CF who had steatorrhea and failure to thrive. Her sweat chloride concentration was 102.0 mM/L. Genetic analysis identified two novel mutations including a splice site mutation (c.1766+2T>C) and a frameshift mutation (c.3908dupA; Asn1303LysfsX6). Pancreatic enzyme replacement and fat-soluble vitamin supplementation enabled the patient to get a catch-up growth. This is the first report of a Korean patient with CF demonstrating pancreatic insufficiency. CF should therefore be considered in the differential diagnosis of infants with steatorrhea and failure to thrive.

Immunogenicity and safety of a multicomponent meningococcal serogroup B vaccine in healthy adolescents in Korea--A randomised trial.

BACKGROUND Neisseria meningitidis serogroup B is a significant cause of septicaemia and meningitis worldwide. This phase 3 randomised, controlled study assessed the immunogenicity and safety of a multicomponent meningococcal serogroup B vaccine, 4CMenB, in healthy Korean adolescents. METHODS 264 adolescents (11-17 years old) were randomised to receive two doses, one month apart, of 4CMenB or control vaccines [placebo followed by one dose of a quadrivalent meningococcal ACWY glycoconjugate vaccine (MenACWY-CRM)]. Immunogenicity was evaluated by serum bactericidal assay with human complement (hSBA) against three serogroup B test strains specific for individual vaccine antigens (fHbp, NadA or PorA P1.4), and by enzyme-linked immunosorbent assay (ELISA) against the NHBA antigen. Solicited reactions and adverse events (AEs) were assessed. RESULTS One month post-second vaccination, 98%, 97%, and 97% of subjects in the 4CMenB group achieved hSBA titres ≥ 4 against the fHbp, NadA and PorA test strains, respectively, while percentages in the Control group were comparable to baseline (27%, 16%, and 17%, respectively). Geometric mean ELISA concentrations (GMCs) against NHBA increased 52-fold relative to baseline in the 4CMenB group, while there was no substantial increase in GMCs in the Control group (1.05-fold). Frequencies of solicited reactions after any vaccination were higher in the 4CMenB group than in the Control group, although most reactions were of short duration and mild to moderate intensity. There were no vaccine-related serious AEs. CONCLUSIONS Two doses of 4CMenB induced robust immune responses against the vaccine antigens and were well tolerated, with no safety concerns identified, in Korean adolescents (NCT01973218).