BACKGROUND/AIMS: The serum anti-Helicobacter pylori (H. pylori) immunoglobulin G (IgG) and serum pepsinogen (PG) assays are widely used to screen for gastric cancer. An equivocal serology test finding indicates IgG titer between the positive and negative test findings. This study aims to evaluate the long-term follow-up result after an equivocal test finding on the serum anti-H. pylori IgG assay. METHODS: Koreans aged 18 years or older with an equivocal serum anti-H. pylori IgG assay finding were included. Subjects were excluded if they did not undergo H. pylori serology test, serum PG assay, and upper gastrointestinal (UGI) endoscopy on the same day at our center. The annual test findings were followed-up using the same methods. RESULTS: Of the 7,178 subjects who underwent the serum assays and UGI endoscopy on the same day, 274 (3.8%) subjects showed an equivocal H. pylori serology test finding. Of the 98 subjects who were followed-up, 58 (59.2%) showed seropositive finding at the mean follow-up period of 30.6±12.4 months. Subjects with seroconversion showed a higher initial serum PG I (p=0.023) and PG II (p=0.036) levels than those without seroconversion. CONCLUSIONS: An equivocal H. pylori serology test finding was not rare (3.8%) in Korean adults, and 60% of equivocal subjects showed seroconversion within 3 years. Higher seroconversion rates in subjects with high PG I and PG II levels suggest that intact gastric secreting ability plays a role in the survival of H. pylori. Therefore, equivocal subjects with increased serum PG levels should be considered as potential seropositive subjects.
Adult ; Endoscopy ; Follow-Up Studies ; Helicobacter pylori ; Helicobacter* ; Humans ; Immunoglobulin G ; Pepsinogen A ; Seroconversion ; Stomach Neoplasms

PURPOSE: Previous studies have demonstrated the immunogenicity and safety of the co-administration of the trivalent inactivated influenza vaccine (IIV3) with the polysaccharide pneumococcal vaccine (PPV) or pneumococcal conjugate vaccine (PCV). However, there is no direct comparison study that evaluates the immunogenicity and safety of IIV3 given concomitantly with PCV13 or PPV23 in the elderly. MATERIALS AND METHODS: During the 2012-2013 influenza vaccination period, 224 healthy elderly volunteers aged 65 years and older randomly received IIV3 given concomitantly with either PCV13 (PCV13+IIV3) or PPV23 (PPV23+IIV3) in a 1:1 ratio. Serum hemagglutination-inhibiting antibodies for IIV3 were measured at the time of vaccination and 1 month after vaccination. Adverse events were recorded prospectively in a clinical diary during a 7-day period. RESULTS: A total of 220 participants blood samples for analysis of immunogenicity and kept a clinical diary for safety analysis (PCV13+IIV3, n=110; PPV23+IIV3, n=110). One month after vaccination, both groups satisfied the Committee for Medical Products for Human Use criteria for A/H1N1, A/H3N2 and B strains, showing comparable seroprotection rates, seroconversion rates and geometric mean titer fold. The assessments of immunogenicity were similar in both groups. The most common local and systemic reactions were pain at the injection site and generalized myalgia. They were generally mild or moderate in intensity. The adverse events were not statistically different between the two groups. CONCLUSION: PCV13+IIV3 and PPV23+IIV3 demonstrated similar immunogenicity and safety in the elderly.
Aged* ; Antibodies ; Humans ; Influenza Vaccines* ; Influenza, Human* ; Myalgia ; Prospective Studies ; Seroconversion ; Streptococcus pneumoniae ; Vaccination ; Volunteers

PURPOSE: A phase I clinical trial was conducted to evaluate the immunogenicity and safety of newly developed egg-cultivated trivalent inactivated split influenza vaccine (TIV) in Korea. MATERIALS AND METHODS: The TIV was administered to 43 healthy male adults. Subjects with high pre-existing titers were excluded in a screening step. Immune response was measured by a hemagglutination inhibition (HI) assay. RESULTS: The seroprotection rates against A/California/7/2009 (H1N1), A/Perth/16/2009 (H3N2) and B/Brisbane/60/2009 were 74.42% [95% confidence interval (CI): 61.38–87.46], 72.09% (95% CI: 58.69–85.50), and 86.05% (95% CI: 75.69–96.40), respectively. Calculated seroconversion rates were 74.42% (95% CI: 61.38–87.46), 74.42% (95% CI: 61.38–87.46), and 79.07% (95% CI: 66.91–91.23), respectively. There were 25 episodes of solicited local adverse events in 21 subjects (47.73%), 21 episodes of solicited general adverse events in 16 subjects (36.36%) and 5 episodes of unsolicited adverse events in 5 subjects (11.36%). All adverse events were grade 1 or 2 and disappeared within three days. CONCLUSION: The immunogenicity and safety of TIV established in this phase I trial are sufficient to plan a larger scale clinical trial.
Adult* ; Hemagglutination ; Humans ; Influenza Vaccines* ; Influenza, Human* ; Korea ; Male ; Mass Screening ; Seroconversion

During the highly pathogenic avian influenza (HPAI) H5N8 virus outbreak in Korea, a dog in layer farm contaminated by H5N8 was reported seropositive for HPAI H5N8. To investigate the possibility of adaptation and transmission of HPAI H5N8 to dogs, we experimentally inoculated dogs with H5N8. Viral genes were weakly detected in nasal swabs and seroconversions in inoculated and contact dogs. Although the H5N8 virus did not induced severe clinical signs to dogs, the results suggest that surveillance of farm dogs should continue as a species in which the avian influenza virus may acquire infectivity to mammals through frequent contact with the virus.
Agriculture ; Animal Experimentation ; Animals ; Dogs* ; Genes, Viral ; Influenza in Birds* ; Korea ; Mammals ; Seroconversion ; Virulence

BACKGROUND: The aim of this study was to compare the long-term efficacy of entecavir (ETV) and lamivudine (LAM) therapy in children with chronic hepatitis B (CHB) who had not received nucleoside analogue treatment. METHODS: In this multicenter, retrospective study, we included pediatric CHB patients younger than 20 years who received ETV or LAM treatment for at least 12 months and had no concomitant diseases. All of the patients were followed up every 1 to 3 months. At each visit, the patients underwent clinical evaluation and biochemical testing. RESULTS: Eight (53.3%), 14 (93.3%), and 2 (15.4%) of the ETV-treated patients achieved virologic suppression, alanine aminotransferase (ALT) normalization and hepatitis B e antigen (HBeAg) seroconversion, respectively, at 1 year. In the ETV group, the cumulative rate of virologic suppression at 3 years was 91.7%, which was significantly higher than that in the LAM group (P < 0.001). The mean duration of treatment before virologic suppression was shorter in the ETV group than in the LAM group (P = 0.040). The cumulative rate of seroconversion in the ETV group at 3 years was 39.4%, which was not significantly different from that in the LAM group (P = 0.439). The ETV group showed lower cumulate rates of virologic breakthrough (33.3% at 6 years) and genotypic mutation than the LAM group (P = 0.033 and P = 0.011, respectively). CONCLUSION: ETV is superior to LAM in pediatric CHB treatment because of its higher virologic suppression rate and lower cumulative rates of virologic breakthrough and genotypic mutation.
Alanine Transaminase ; Child ; Hepatitis B ; Hepatitis B, Chronic ; Hepatitis, Chronic ; Humans ; Lamivudine ; Retrospective Studies ; Seroconversion

BACKGROUND: The frequency with which the 2 B lineages have been found to cocirculate in a season has been on the rise, which has spurred the need for a quadrivalent influenza vaccine (QIV) to protect against both B lineages. The World Health Organization (WHO) recommended that QIV include both B lineages beginning in the 2013–2014 flu season. This study was conducted to evaluate the immunogenicity and safety of an egg-cultivated QIV in healthy Korean children and adolescents aged ≥ 6 months to < 19 years. METHODS: A total of 528 subjects were randomized 4:1 to receive either a QIV (GC3110A) or a trivalent influenza vaccine. Hemagglutination inhibition antibody responses were assessed 28 days after the last dose. Safety was also evaluated. RESULTS: The proportion of subjects in the GC3110A group who achieved seroconversion was confirmed to exceed 40% across all age groups. The proportion of subjects aged ≥ 6 months to < 3 years in the GC3110A group who achieved seroprotection failed to meet the Ministry of Food and Drug Safety (MFDS) standard of 70%. Potential causes may include the small number of subjects, as well as the small dosage. However, results pertaining to the other age groups satisfied the MFDS standard. The safety profile was also comparable to that of the control. CONCLUSION: The new quadrivalent split influenza vaccine may offer broader protection to children and adolescents aged ≥ 3 years to < 19 years of age against both influenza B lineages than the existing trivalent influenza vaccines (Registered at the ClinicalTrials.gov NCT02541253).
Adolescent ; Antibody Formation ; Child* ; Hemagglutination ; Humans ; Influenza Vaccines* ; Influenza, Human* ; Seasons ; Seroconversion ; World Health Organization

OBJECTIVES: An atypical Shigella flexneri strain with a plural agglutination pattern [i.e., reacting not only with serum samples containing type antigen II but also with serum samples containing group antigens (3)4 and 7(8)] was selected for genome sequencing, with the aim of obtaining additional comparative information about such strains. METHODS: The genomic DNA of atypical S. flexneri strain NCCP 15744 was sequenced using an Ion Torrent PGM sequencing machine (Life Technologies, USA). The raw sequence data were preprocessed and reference-assembled in the CLC Assembly Cell software (version 4.0.6; CLC bio, USA). RESULTS: Ion Torrent sequencing produced 1,450,025 single reads with an average length of 144 bp, totaling ~209 Mbp. The NCCP 15744 genome is composed of one chromosome and four plasmids and contains a gtrX gene. Among the published genome sequences of S. flexneri strains, including 2457T, Sf301, and 2002017, strain NCCP 15744 showed high similarity with strain 2002017. The differences between NCCP 15744 and 2002017 are as follows: i) NCCP 15744 carries four plasmids whereas 2002017 carries five; ii) 19 genes (including CI, CII, and cro) were lost in the SHI-O genomic island of NCCP 15744 and six genes were gained as compared with strain 2002017. CONCLUSION: Strain NCCP 15744 is genetically similar to 2002017, but these two strains have different multilocus sequence types and serotypes. The exact reason is unclear, but the 19 lost genes may be responsible for the atypical seroconversion of strain NCCP 15744.
Agglutination ; DNA ; Genome* ; Genomic Islands ; Genomics ; Korea* ; Plasmids ; Sequence Analysis ; Seroconversion ; Serogroup ; Shigella flexneri* ; Shigella*

A pandemic influenza A (H1N1) virus strain was isolated from a pig farm in Korea in December 2009. The strain was propagated in and isolated from both the Madin-Darby canine kidney cell line and embryonated eggs. The partial and complete sequences of the strain were identical to those of A/California/04/2009, with >99% sequence similarity in the HA, NA, M, NS, NP, PA, PB1, and PB2 genes. The isolated strain was inactivated and used to prepare a swine influenza vaccine. This trial vaccine, containing the new isolate that has high sequence similarity with the pandemic influenza A (H1N1) virus, resulted in seroconversion in Guinea pigs and piglets. This strain could therefore be a potential vaccine candidate for swine influenza control in commercial farms.
Agriculture ; Animals ; Cell Line ; Eggs ; Guinea Pigs ; Influenza Vaccines ; Influenza, Human* ; Kidney ; Korea* ; Orthomyxoviridae* ; Ovum ; Pandemics* ; Seroconversion ; Swine

The primary goal of therapy for chronic hepatitis B (CHB) is to prevent liver disease progression. Hepatitis B surface antigen (HBsAg) seroclearance or seroconversion is regarded as an optimal endpoint to discontinue treatment. However, HBsAg seroclearance occurs very rarely with nucleos(t)ide analog (NUC) treatment, and long-term, almost indefinite, NUC treatment is required for the majority of patients. In patients with drug-resistant hepatitis B virus (HBV), a combination of tenofovir disoproxil fumarate (TDF) and entecavir (ETV), which is currently regarded as the strongest combination therapy against HBV, would be potentially safe to prevent the emergence of additional HBV resistance mutations. However, long-term tolerance data are lacking, and cost may be an issue for combination therapies. Several recent, well-designed, randomized controlled trials have shown that TDF mono-therapy provides similar antiviral efficacy compared with the combination of TDF and ETV. Furthermore, no additional HBV resistance mutations emerged during TDF monotherapy for up to 96 weeks. Considering a comparable antiviral efficacy, extremely low risk of TDF-resistance, lower cost, and better safety potential, TDF monotherapy would be a reasonable choice for the treatment of drug-resistant patients with CHB.
Hepatitis B Surface Antigens ; Hepatitis B virus ; Hepatitis B, Chronic* ; Hepatitis, Chronic* ; Humans ; Lamivudine ; Liver Diseases ; Seroconversion ; Tenofovir

Although Q fever is an important zoonotic infection with a worldwide distribution, no human isolates of Coxiella burnetii have been identified in Korea. For the first time, we identified the nucleotide sequence of C. burnetii from a 32-year-old man with an acute febrile illness in Korea. Diagnosis of acute Q fever was confirmed by seroconversion using indirect immunofluorescence antibody assays. Phylogenetic analysis demonstrated high sequence similarity (99.6%–100%) with C. burnetii 16S rRNA sequences identified from the reservoir. These results are the first genetic analysis of C. burnetii in a human case of Q fever in Korea.
Adult ; Base Sequence ; Coxiella burnetii* ; Coxiella* ; Diagnosis ; Fluorescent Antibody Technique, Indirect ; Humans ; Korea* ; Q Fever ; Seroconversion ; Zoonoses