Epigenetic scars in regulatory T cells are retained after successful treatment of chronic hepatitis C with direct-acting antivirals.

BACKGROUND & AIMS: Chronic hepatitis C virus (HCV) infection results in abnormal immunological alterations, which are not fully normalized after viral elimination by direct-acting antiviral (DAA) treatment. Here we longitudinally examined phenotypic, transcriptomic, and epigenetic alterations in peripheral blood regulatory T (TREG) cells from patients with chronic HCV infection according to DAA treatment. METHODS: Patients with chronic genotype 1b HCV infection who achieved sustained virologic response (SVR) by DAA treatment and age-matched healthy donors were recruited. Phenotypic characteristics of TREG cells were investigated through flow cytometry analysis. Moreover, transcriptomic and epigenetic landscape of TREG cells were analyzed using RNA-seq and ATAC-seq analysis. RESULTS: The TREG cell population-especially the activated TREG cell subpopulation-was expanded in peripheral blood during chronic HCV infection, and this expansion was sustained even after viral clearance. RNA-seq analysis revealed that viral clearance did not abrogate the inflammatory features of these TREG cells, such as TREG activation and TNF signal. Moreover, ATAC-seq analysis showed inflammatory imprinting in the epigenetic landscape of TREG cells from patients, which remained after treatment. These findings were further confirmed by intracellular cytokine staining, demonstrating that TREG cells exhibited inflammatory features and TNF production in chronic HCV infection that were maintained after viral clearance. CONCLUSIONS: Overall, our results showed that during chronic HCV infection, the expanded TREG cell population acquired inflammatory features at phenotypic, transcriptomic, and epigenetic levels, which were maintained even after successful viral elimination by DAA treatment. Further studies are warranted to examine the clinical significance of sustained inflammatory features in the TREG cell population after recovery from chronic HCV infection. IMPACT AND IMPLICATIONS: During chronic HCV infection, several immune components are altered both quantitatively and qualitatively. The recent introduction of DAAs led to a high cure rate of chronic HCV infection. Nevertheless, we have demonstrated that inflammatory features of TREG cells are maintained at phenotypic, transcriptomic, and epigenetic levels even after successful DAA treatment. Further in-depth studies are required to investigate the long-term clinical outcomes of patients who have recovered from chronic HCV infection.

Enhancing ACLS training effects through video-assisted boosting methods: A comparative analysis of self-simulation and model simulation videos.

AIMS: To assess the impact of learner-participation and instructor-led simulation videos on nurses' CPR skills, focusing on iterative learning to boost proficiency in ACLS. BACKGROUND: Advanced cardiac life support (ACLS) training is crucial for nurses, especially to improve cardiopulmonary resuscitation (CPR) proficiency, for which an effective training strategy is needed. DESIGN: A quasi-experimental, pretest-posttest design was implemented to assess the impact of self-simulation and model simulation videos on sustaining CPR education. METHODS: The research was carried out at a university hospital in Korea from August 2021 to July 2022. A total of 110 nurses were allocated into three groups based on the building of their workplace in the hospital. Each group watched training videos at 4-month intervals after the simulation training. The self-video group viewed simulations featuring their participation, while the model video group watched instructor-led simulations. A comparison group participated in the simulations without subsequent video boosting. RESULTS: Both the self-video and model video groups exhibited significantly superior ACLS performance compatred with the comparison group at both four months (H = 70.33, p <.001) and eight months (H = 81.52, p <.001) following the intervention, with large effect sizes (self-video vs. comparison: d = 4.73 at four months, d = 12.54 at eight months; model video vs. comparison: d = 4.53 at four months, d = 11.01 at eight months). ACLS knowledge scores also significantly increased over time in both intervention groups (self-video: χ² = 22.09, p <.001; model video: χ² = 24.13, p <.001), but not in the comparison group (χ² = 3.75, p =.153). There were no significant differences among the groups in terms of CPR self-efficacy or stress at either time point. CONCLUSION: Supplementary training using simulation videos is an effective method for maintaining and enhancing nurses' ACLS competency, offering a sustainable approach to repetitive CPR training. This study underscores the value of incorporating recorded simulation videos in clinical training, offering insights into efficient methods for continuous learning and CPR proficiency among nursing professionals.

Exploring the impact of the mentoring new nurses for transition and empowerment program led by clinical nurse educators in South Korea: A mixed-methods study.

BACKGROUND: "New nurses" are those with less than a year of work experience at a hospital. To address the challenges of new nurses caused by their limited experience, the Mentoring New Nurses for Transition and Empowerment Program (MNTEP) was designed based on the Stress-Appraisal-Coping Model of Lazarus and Folkman. OBJECTIVES: This study aimed to explore the impact of the MNTEP, in which clinical nurse educators teach stress-coping strategies, on the clinical transition of new nurses in South Korea. DESIGN: This study used a mixed-methods design with a pretest-posttest non-equivalent comparison group and focus group interviews (FGIs). SETTINGS: The research was conducted at a hospital in South Korea. PARTICIPANTS: The intervention and comparison groups comprised 30 and 28 new nurses, respectively. Also, 12 MNTEP participants were subjected to three separate FGIs. METHODS: To comprehensively assess the program's effects, quantitative data were collected through self-report surveys, while qualitative data were obtained from March 2022 to March 2023 using semi-structured interviews that allowed for open-ended responses. RESULTS: There were significant differences in mean self-efficacy scores (t = 2.45, p = 0.017) and perceived social support from clinical nurse educators (F = 4.51, p = 0.038) between the intervention and comparison groups. Additionally, significant changes were observed in the field adaptation pre-test and post-test scores within the intervention group (t = -3.12, p = 0.004). However, there was no statistically significant difference between the groups in terms of active and passive coping strategies. FGIs yielded two main themes: (1) gaining positive energy through empowerment and solidarity; and (2) clinical nurse educators sharing strategies for improved role adaptation and capacity building. CONCLUSIONS: MNTEP led by clinical nurse educators positively influenced new nurses' self-efficacy and facilitated their transition to clinical settings. These findings underscore the importance of mentorship programs and clinical nurse educators.

Persistent differences in the immunogenicity of the two COVID-19 primary vaccines series, modulated by booster mRNA vaccination and breakthrough infection.

INTRODUCTION: The long-term impact of initial immunogenicity induced by different primary COVID-19 vaccine series remains unclear. METHODS: A prospective cohort study was conducted at 10 tertiary hospitals in Korea from March 2021 to September 2022. Immunogenicity assessments included anti-spike protein antibody (Sab), SARS-CoV-2-specific interferon-gamma releasing assay (IGRA), and multiplex cytokine assays for spike protein-stimulated plasma. Spike proteins derived from wild-type SARS-CoV-2 and alpha variant (Spike1) and beta and gamma variant (Spike2) were utilized. RESULTS: A total of 235 healthcare workers who had received a two-dose primary vaccine series of either ChAdOx1 or BNT162b2, followed by a third booster dose of BNT162b2 (166 in the ChAdOx1/ChAdOx1/BNT162b2 (CCB) group and 69 in the BNT162b2/BNT162b2/BNT162b2 (BBB) group, based on the vaccine series) were included. Following the primary vaccine series, the BBB group exhibited significantly higher increases in Sab levels, IGRA responses, and multiple cytokines (CCL2/MCP-1, CCL3/MIP-1α, CCL4/MIP-1ß, interleukin (IL)-1ra, IFN-γ, IL-2, IL-4, and IL-10) compared to the CCB group (all P < 0.05). One month after the third BNT162b2 booster, the CCB group showed Sab levels comparable to those of the BBB group, and both groups exhibited lower levels after six months without breakthrough infections (BIs). However, among those who experienced BA.1/2 BIs after the third booster, Sab levels increased significantly more in the BBB group than in the CCB group (P < 0.001). IGRA responses to both Spike1 and Spike2 proteins were significantly stronger in the BBB group than the CCB group after the third booster, while only the Spike2 response were higher after BIs (P = 0.007). The BBB group exhibited stronger enhancement of T-cell cytokines (IL-2, IL-4, and IL-17A) after BIs than in the CCB group (P < 0.05). CONCLUSION: Differences in immunogenicity induced by the two primary vaccine series persisted, modulated by subsequent booster vaccinations and BIs.

Effectiveness of COVID-19 XBB.1.5 monovalent mRNA vaccine in Korea: interim analysis.

As coronavirus disease-2019 (COVID-19) becomes an endemic disease, the virus continues to evolve and become immunologically distinct from previous strains. Immune imprinting has raised concerns about bivalent mRNA vaccines containing both ancestral virus and Omicron variant. To increase efficacy against the predominant strains as of the second half of 2023, the updated vaccine formulation contained only the mRNA of XBB.1.5 sublineage. We conducted a multicenter, test-negative, case-control study to estimate XBB.1.5 monovalent vaccine effectiveness (VE) and present the results of an interim analysis with data collected in November 2023. Patients who underwent COVID-19 testing at eight university hospitals were included and matched based on age (19-49, 50-64, and ≥65 years) and sex in a 1:1 ratio. VE was calculated using the adjusted odds ratio derived from multivariable logistic regression. Of the 992 patients included, 49 (5.3%) received the XBB.1.5 monovalent vaccine at least 7 days before COVID-19 testing. Patients with COVID-19 (cases) were less likely to have received the XBB.1.5 monovalent vaccine (case 3.5% vs. control 7.2%, p=0.019) and to have a history of COVID-19 within 6 months (2.2% vs. 4.6%, p=0.068). In contrast, patients with COVID-19 were more likely to be healthcare workers (8.2% vs. 3.0%, p=0.001) and to have chronic neurological diseases (16.7% vs. 11.9%, p=0.048). The adjusted VE of the XBB.1.5 monovalent mRNA vaccine was 56.8% (95% confidence interval: 18.7-77.9%). XBB.1.5 monovalent mRNA vaccine provided significant protection against COVID-19 in the first one to two months after vaccination.

Interim Estimates of 2023-2024 Seasonal Influenza Vaccine Effectiveness Among Adults in Korea.

In the 2023-2024 season, the influenza epidemic in South Korea peaked earlier than in recent years. In this study, we aimed to estimate the interim vaccine effectiveness (VE) of the influenza vaccination to prevent influenza during the early season. From November 1, 2023, to December 31, 2023, we enrolled 2,632 subjects with influenza-like illness from eight hospitals participating in hospital-based influenza morbidity and mortality surveillance. A retrospective test-negative case-control study was conducted to estimate the VE. The results showed an adjusted VE of 22.5% (95% confidence interval [CI], 6.6 to 35.8) for the total population. The adjusted VE was 22.3% (95% CI, 6.1 to 35.7) for influenza A and 9.4% (95% CI, -51.3 to 45.7) for influenza A/H1N1. Full results of the analysis will be reported.

Managing a difficult airway due to supraglottic masses: successful videolaryngoscopic intubation after induction of general anesthesia.

BACKGROUND: While awake, flexible bronchoscopic intubation has long been considered the gold standard for managing anticipated difficult airways, the videolaryngoscope has emerged as a viable alternative. In addition, the decision to perform awake intubation or to proceed with airway management after induction of general anesthesia should be grounded in a comprehensive assessment of risks and benefits. CASE PRESENTATION: A 41-year old female patient was scheduled for excision of bilateral, mobile, and pedunculated masses on both aryepiglottic folds, which covered almost the entire upper part of the glottis. We conducted a comprehensive evaluation of the patient's signs and symptoms, which included neither stridor nor dyspnea in any position, along with the otolaryngologist's opinion and the findings from the laryngeal fiberscopic examination. Given the potential challenges and risks associated with awake flexible bronchoscopic intubation for this patient, we decided to proceed with gentle tracheal intubation using a videolaryngoscope under general anesthesia. In case of failed mask ventilation and tracheal intubation, we had preplanned strategies, including awakening the patient or performing an emergent tracheostomy, along with preparations to support these strategies. Ensuring that mask ventilation was maintained with ease, the patient was sequentially administered intravenous propofol, remifentanil, and rocuronium. Under sufficient depth of anesthesia, intubation using a videolaryngoscope was successfully performed without any complications. CONCLUSIONS: Videolaryngoscopic intubation after induction of general anesthesia can be a feasible alternative for managing difficult airways in patients with supraglottic masses. This approachshould be based on a comprehensive preoperative evaluation, adequate preparation, and preplanned strategies to address potential challenges, such as inadequate oxygenation and unsuccessful tracheal intubation.

Effects of Taekkyon-based exercise program on balance, lower extremity strength, and gait parameters in community-dwelling older women: Randomized controlled trial.

BACKGROUND: As individuals age, they experience a decline in muscle strength and balance, leading to diminished functional capacity and an increased risk of falls. The purpose of the current study was to investigate the effects of the Taekkyon-based exercise program on balance, muscle strength, and gait ability in women aged over 65-year-old residing in the local community. METHODS: Forty-eight subjects were randomly allocated into the Taekkyon-based exercise program as an experimental group (EG = 25; mean age: 71.68 ±â€…3.26) or a fall prevention program as a control group (CG = 23; mean age: 73.65 ±â€…5.88). EG participants received 1-hour Taekkyon exercise sessions twice a week for 12 consecutive weeks. CG participants received a typical fall prevention program. The measurements in each group included assessments of balance levels (the timed up-and-go test, one-leg stance, and functional reach test), lower extremity strength (the 5-chair stand test and 30-second chair stand test), and gait parameters (cadence, step length, step width, stride length, stride time, and gait velocity) before and after the intervention. RESULTS: After the intervention, balance (timed up-and-go test, one-leg stance, and functional reach test), lower extremity strength (5-chair stand test and 30-second chair stand test), and gait parameters (cadence, stride time, and gait velocity) showed a significant improvement in EG participants compared to CG participants (P < .05). Compared to the normal value of balance ability and strength of elderly women over 65 years of age, most outcomes were greater than average normal values for those receiving Taekkyon exercise. CONCLUSION: Taekkyon-based exercise program was more effective in improving balance, lower extremity strength, and gait capacity than the usual fall prevention program in elderly women over 65 years of age. Its effects can approach normal values for women in this age group. The 12-week Taekkyon-based exercise program could be useful as part of a fall prevention program to elderly people.

Developing and evaluating an evidence-based practice research competency enhancement program for clinical nurses in Korea: a pilot study.

BACKGROUND: Evidence-based practice (EBP) is crucial for delivering high-quality healthcare and effective self-care. Enhancing clinical nurses' research competencies through structured mentorship is key to the widespread application of EBP. This study evaluated a newly developed Research Competency Enhancement Program (RCEP), aimed at bolstering EBP among experienced nurses. METHODS: Conducted in a tertiary university hospital in Korea, this single-group study employed a pretest-post-test design and a mixed-methods approach. The RCEP involved 11 experienced clinical nurses in an 8-week intervention, featuring mentor-led workshops, interactive sessions, and resource-driven activities. Data were collected using the Evidence-Based Practice Beliefs Scale (EBPB), the Evidence-Based Practice Attitude Scale (EBPA), and the Research Practice Ability (RPA) tool, alongside qualitative feedback. These measures assessed the program's feasibility, acceptability, and preliminary effectiveness. RESULTS: The quantitative analysis indicated significant improvements in research competency post-intervention. Mean scores on the EBPB and RPA scales increased (Z = -2.53, p = .011; Z = -2.66, p = .008). Participants described the RCEP as inspirational and challenging, creating an environment conducive to research. Facilitators included mentor support and innovative learning tools, while barriers were internet connectivity and scheduling conflicts. Suggestions for improvement included more hands-on sessions, small team collaborations, and integration with academic institutions. CONCLUSION: The RCEP, facilitated by EBP mentors, significantly improved the research competencies and attitudes of clinical nurses towards EBP. The study underscores the importance of continual RCEP refinement, integrating structured, interactive, and collaborative elements to further empower nurses in evidence-based practice. The program shows promise in enhancing research competencies and fostering a commitment to EBP in clinical settings.

Impact of preoperative nonselective beta-blocker use on acute kidney injury after living donor liver transplantation: Propensity score analysis.

INTRODUCTION AND OBJECTIVES: Acute kidney injury (AKI) is prevalent and has deleterious effects on postoperative outcomes following liver transplantation (LT). The impact of nonselective beta-blockers (NSBBs) in patients with liver cirrhosis remains controversial. This study investigated the association between preoperative NSBB use and AKI after living donor LT (LDLT). PATIENTS AND METHODS: We evaluated 2,972 adult LDLT recipients between January 2012 and July 2022. The patients were divided into two groups based on the preoperative NSBB use. Propensity score matched (PSM) and inverse probability of treatment weighting (IPTW) analyses were performed to evaluate the association between preoperative NSBB use and postoperative AKI. Multiple logistic regression analyses were also used to identify the risk factors for AKI. RESULTS: The overall incidence of AKI was 1,721 (57.9%) cases. The NSBB group showed a higher incidence of AKI than the non-NSBB group (62.4% vs. 56.7%; P = 0.011). After PSM and IPTW analyses, no significant difference in the incidence of AKI was found between the two groups (Odds ratio, OR 1.13, 95% confidence interval, CI 0.93-1.37, P = 0.230, PSM analysis; OR 1.20, 95% CI 0.99-1.44, P = 0.059, IPTW analysis). In addition, preoperative NSBB use was not associated with AKI after multivariate logistic regression analysis (OR 1.16, 95% CI 0.96-1.40, P = 0.118). CONCLUSIONS: Preoperative NSBB use was not associated with AKI after LDLT. Further studies are needed to validate our results.

Effectiveness of Bivalent mRNA Booster Vaccine Against COVID-19 in Korea.

BACKGROUND: Bivalent booster mRNA vaccines containing the omicron-variant strains have been introduced worldwide in the autumn of 2022. Nevertheless, the omicron subvariants evoked another large coronavirus disease 2019 (COVID-19) pandemic wave in late 2022 and early 2023. METHODS: A retrospective, test-negative, case-control study was conducted to estimate the vaccine effectiveness (VE) of bivalent COVID-19 vaccines in 8 university hospitals between January and February 2023. The case and control groups were divided based on nasopharyngeal COVID-19 real-time polymerase chain reaction results and matched based on age, sex, hospital, and date (week) of the test performed. The VE of the BA.1- or BA.4/BA.5-based mRNA vaccines were estimated. VE was calculated using the 1-adjusted odds ratio from multivariable logistic regression. RESULTS: In total, 949 patients and 947 controls were enrolled in this study. VE for the BA.4/BA.5-based bivalent mRNA vaccine was 43% (95% confidence interval [CI], 17, 61%). In subgroup analysis based on age and underlying medical conditions, BA.4/BA.5-based bivalent mRNA vaccine was effective against old adults aged ≥ 65-years (VE, 55%; 95% CI, 23, 73%) and individuals with comorbidities (VE, 54%; 95% CI, 23, 73%). In comparison, the BA.1-based bivalent mRNA vaccine did not demonstrate statistically significant effectiveness (VE, 25%; 95% CI, -8, 49%). CONCLUSION: The BA.4/BA.5-based bivalent mRNA booster vaccine provided significant protection against COVID-19 in the Korean adults, especially in the older adults aged ≥ 65 years and in individuals with underlying medical conditions.

Val43 residue of NsrR is crucial for the nitric oxide response of Salmonella Typhimurium.

ABSTRACT: In pathogenic bacteria, the flavohemoglobin Hmp is crucial in metabolizing the cytotoxic levels of nitric oxide (NO) produced in phagocytic cells, contributing to bacterial virulence. Hmp expression is predominantly regulated by the Rrf2 family transcription repressor NsrR in an NO-dependent manner; however, the underlying molecular mechanism in enterobacteria remains poorly understood. In this study, we identified Val43 of Salmonella Typhimurium NsrR (StNsrR) as a critical amino acid residue for regulating Hmp expression. The Val43-to-Ala-substituted mutant NsrR isolated through random and site-directed mutagenesis showed high binding affinity to the target DNA irrespective of NO exposure, resulting in a severe reduction in hmp transcription and slow NO metabolism in Salmonella under NO-producing conditions. Conversely, the Val43-to-Glu-substituted NsrR caused effects similar to nsrR null mutation, which directed hmp transcription and NO metabolism in a constitutive way. Comparative analysis of the primary sequences of NsrR and another NO-sensing Rrf2 family regulator, IscR, from diverse bacteria, revealed that Val43 of enterobacterial NsrR corresponds to Ala in Pseudomonas aeruginosa or Streptomyces coelicolor NsrR and Glu in enterobacterial IscR, all of which are located in the DNA recognition helix α3. The predicted structure of StNsrR in complex with the hmp DNA suggests dissimilar spatial stoichiometry in the interactions of Val43 and its substituted residues with the target DNA, consistent with the observed phenotypic changes in StNsrR Val43 mutants. Our findings highlight the discriminative roles of the NsrR recognition helix in regulating species-specific target gene expression, facilitating effective NO detoxification strategies in bacteria across diverse environments. IMPORTANCE: The precise regulation of flavohemoglobin Hmp expression by NsrR is critical for bacterial fitness, as excessive Hmp expression in the absence of NO can disturb bacterial redox homeostasis. While the molecular structure of Streptomyces coelicolor NsrR has been recently identified, the specific molecular structures of NsrR proteins in enterobacteria remain unknown. Our discovery of the crucial role of Val43 in the DNA recognition helix α3 of Salmonella NsrR offers valuable insights into the Hmp modulation under NO stress. Furthermore, the observed amino acid polymorphisms in the α3 helices of NsrR proteins across different bacterial species suggest the diverse evolution of NsrR structure and gene regulation in response to varying levels of NO pressure within their ecological niches.

Clinical utility of quantitative immunoassays and surrogate virus neutralization tests for predicting neutralizing activity against the SARS-CoV-2 Omicron BA.1 and BA.5 variants.

Developing new antibody assays for emerging SARS-CoV-2 variants is challenging. SARS-CoV-2 surrogate virus neutralization tests (sVNT) targeting Omicron BA.1 and BA.5 have been devised, but their performance needs to be validated in comparison with quantitative immunoassays. First, using 1749 PRNT-positive sera, we noticed that log-transformed optical density (OD) ratio of wild-type (WT) sVNT exhibited better titer-correlation with plaque reduction neutralization test (PRNT) than % inhibition value. Second, we tried 798 dilutional titration tests with 103 sera, but nonlinear correlation between OD ratio and antibody concentration limited titration of sVNT. Third, the titer-correlations of two sVNT kits for BA.1 and two quantitative immunoassays for WT were evaluated with BA.1 and BA.5 PRNT. All tested kits exhibited a linear correlation with PRNT titers, but the sVNT kits exhibited high false-negative rates (cPass-BA.1 kit, 45.4% for BA.1 and 44.2% for BA.5; STANDARD F-BA.1 kit, 1.9% for BA.1 and 2.2% for BA.5), while quantitative immunoassays showed 100% sensitivity. Linear mixed-effects model suggested superior titer-correlation with PRNT for quantitative immunoassays compared to sVNT kits. Taken together, the use of quantitative immunoassays for WT, rather than rapid development of new kits, would be practical for predicting neutralizing activities against emerging new variants.

Coinfection With Severe Fever With Thrombocytopenia Syndrome and Scrub Typhus in Korea.

Background: Scrub typhus and severe fever with thrombocytopenia syndrome (SFTS) are the 2 most common tick-borne infectious diseases in Korea. Every year, an increasing number of cases are reported, which is a public health concern. Therefore, we aimed to investigate the prevalence of SFTS-scrub typhus coinfection in patients with SFTS. Methods: Clinical samples were collected from 129 patients with SFTS. One-step reverse-transcription polymerase chain reaction (PCR) was performed to identify the SFTS virus (SFTSV), and real-time PCR followed by nested PCR was performed to detect the Orientia tsutsugamushi gene for scrub typhus. Phylogenetic analysis was conducted to confirm the evolutionary relationships among different species. Results: Among 129 SFTS cases, 2 patients with SFTSV were positive for O. tsutsugamushi with a prevalence of coinfection of 1.6% (95% confidence interval, .001-.06). Phylogenetic analysis confirmed these as O. tsutsugamushi strain Boryong. Conclusions: Our study found that 1.6% of patients were coinfected with SFTS and scrub typhus infection. We believe that this information will add a new dimension to clinical diagnosis, which should be considered for better public health management. Further research is needed to better understand the ecological transmission dynamics and geographical distribution of SFTSV and O. tsutsugamushi in endemic countries.

Immune Response Kinetics Following a Third Heterologous BNT162b2 Booster Dose After Primary 2-Dose ChAdOx1 Vaccination in Relation to Omicron Breakthrough Infection: A Prospective Nationwide Cohort Study in South Korea.

Background: Immune responses to each vaccine must be investigated to establish effective vaccination strategies for the ongoing coronavirus disease (COVID-19) pandemic. We investigated the long-term kinetics of immune responses after heterologous booster vaccination in relation to Omicron breakthrough infection (BI). Methods: Our study included 373 healthcare workers who received primary ChAdOx1 vaccine doses and a third BNT162b2 vaccine dose. BIs that occurred after the third vaccine were investigated. Blood specimens were collected before and 3 months after the booster dose from participants without BI and 1, 4, and 6 months after BI from participants who experienced BI. Spike-specific binding and neutralizing antibody levels against the wild-type virus, Omicron BA.1, and Omicron BA.5, as well as cellular responses, were analyzed. Results: A total of 346 participants (82 in the no BI group; 192 in the BI group during the BA.1/BA.2 period; 72 in the BI group during the BA.5 period) were included in the analysis. Participants without BI exhibited the highest binding and neutralizing antibody concentrations and greatest cellular response 1 month after the third vaccination, which reached a nadir by the ninth month. Antibody and cellular responses in participants who experienced BI substantially increased postinfection. Neutralizing antibody titers in individuals who experienced BI during the BA.1/BA.2 period showed more robust increase against wild-type virus than against BA.1 and BA.5. Conclusions: Our findings provide evidence of antigenic imprinting in participants who received a heterologous booster vaccination, thereby serving as a foundation for further studies on the impact of BIs on immune responses.

Current Status of Q Fever and the Challenge of Outbreak Preparedness in Korea: One Health Approach to Zoonoses.

Human Q fever, a zoonosis caused by Coxiella burnetii, presents with diverse clinical manifestations ranging from mild self-limited febrile illnesses to life-threatening complications such as endocarditis or vascular infection. Although acute Q fever is a benign illness with a low mortality rate, a large-scale outbreak of Q fever in the Netherlands led to concerns about the possibility of blood transfusion-related transmission or obstetric complications in pregnant women. Furthermore, a small minority (< 5%) of patients with asymptomatic or symptomatic infection progress to chronic Q fever. Chronic Q fever is fatal in 5-50% of patients if left untreated. In South Korea, Q fever in humans was designated as a notifiable infectious disease in 2006, and the number of Q fever cases has increased sharply since 2015. Nonetheless, it is still considered a neglected and under-recognized infectious disease. In this review, recent trends of human and animal Q fever in South Korea, and public health concerns regarding Q fever outbreaks are reviewed, and we consider how a One Health approach could be applied as a preventive measure to prepare for zoonotic Q fever outbreaks.

Content Analysis of Feedback Journals for New Nurses From Preceptor Nurses Using Text Network Analysis.

This study aimed to identify keywords, core topic areas, and subthemes by analyzing feedback journals written by preceptor nurses to new nurses during the preceptorship period and to derive implications through word clustering. A total of 143 preceptor nurses' feedback journals for new nurses from March 2020 to January 2021 were converted into a database using Microsoft Office Excel. Text network analysis was performed using the NetMiner 4.4.3 program. After data preprocessing, simple frequency, degree centrality, closeness centrality, betweenness centrality, and community modularity were analyzed. In the feedback journals, the most central words were "study," "medication," "practice," "nursing," "method," "need," and "effort," whereas frustration, "new nurses" had low centrality. Five subthemes were derived: (1) learning necessity to strengthen new nurses' competency, (2) independence of new nurses, (3) emphasis on accuracy in nursing skills, (4) difficulties in understanding the nursing tasks expected of new nurses, and (5) basic competency of new nurses. The results of this study highlighted the experiences of new nurses and allowed for an assessment of journal feedback content provided by preceptor nurses. As such, the study provides basic data to develop a standardized education and competency empowerment program for preceptor nurses.

Coexisting cytomegalovirus colitis in an immunocompetent patient with Clostridioides difficile colitis: A case report.

BACKGROUND: Clostridioides difficile (C. difficile) colitis is one of the most common infections in hospitalized patients, characterized by fever and diarrhea. It usually improves after appropriate antibiotic treatment; if not, comorbidities should be considered. Cytomegalovirus (CMV) colitis is a possible co-existing diagnosis in patients with C. difficile infection with poor treatment response. However, compared with immunocompromised patients, CMV colitis in immunocompetent patients is not well studied. CASE SUMMARY: We present an unusual case of co-existing CMV colitis in an immunocompetent patient with C. difficile infection. An 80-year-old female patient was referred to the infectious disease department due to diarrhea, abdominal discomfort, and fever for 1 wk during her hospitalization for surgery. C. difficile toxin B polymerase chain reaction on stool samples was positive. After C. difficile infection was diagnosed, oral vancomycin treatment was administered. Her symptoms including diarrhea, fever and abdominal discomfort improved for ten days. Unfortunately, the symptoms worsened again with bloody diarrhea and fever. Therefore, a sigmoidoscopy was performed for evaluation, showing a longitudinal ulcer on the sigmoid colon. Endoscopic biopsy confirmed CMV colitis, and the clinical symptoms improved after using ganciclovir. CONCLUSION: Co-existing CMV colitis should be considered in patients with aggravated C. difficile infection on appropriate treatment, even in immunocompetent hosts.

Distinctive Dynamics and Functions of the CD4+CD25+FOXP3+ Regulatory T Cell Population in Patients with Severe and Mild COVID-19.

Although CD4+CD25+FOXP3+ regulatory T (TREG) cells have been studied in patients with COVID-19, changes in the TREG cell population have not been longitudinally examined during the course of COVID-19. In this study, we longitudinally investigated the quantitative and qualitative changes in the TREG cell population in patients with COVID-19. We found that the frequencies of total TREG cells and CD45RA-FOXP3hi activated TREG cells were significantly increased 15-28 d postsymptom onset in severe patients, but not in mild patients. TREG cells from severe patients exhibited not only increased proliferation but also enhanced apoptosis, suggesting functional derangement of the TREG cell population during severe COVID-19. The suppressive functions of the TREG cell population did not differ between patients with severe versus mild COVID-19. The frequency of TREG cells inversely correlated with SARS-CoV-2-specific cytokine production by CD4+ T cells and their polyfunctionality in patients with mild disease, suggesting that TREG cells are major regulators of virus-specific CD4+ T cell responses during mild COVID-19. However, such correlations were not observed in patients with severe disease. Thus, in this study, we describe distinctive changes in the TREG cell population in patients with severe and mild COVID-19. Our study provides a deep understanding of host immune responses upon SARS-CoV-2 infection in regard to TREG cells.

Clinically differential diagnosis of human granulocytic anaplasmosis and severe fever with thrombocytopenia syndrome.

This study analyzed HGA and SFTS in patients with suspected tick-borne infection by focusing on key differences that clinicians can easily recognize. A retrospective analysis was performed on confirmed patients with HGA or SFTS in 21 Korean hospitals from 2013 to 2020. A scoring system was developed by multivariate regression analysis and accuracy assessment of clinically easily discriminable parameters was performed. The multivariate logistic regression analysis revealed that sex (especially male sex) (odds ratio [OR] 11.45, P = 0.012), neutropenia (< 1500) (OR 41.64, P < 0.001), prolonged activated partial thromboplastin time (OR 80.133, P < 0.001), and normal C-reactive protein concentration (≤ 1.0 mg/dL; OR 166.855, P = 0.001) were significantly associated with SFTS but not with HGA. Each factor, such as meaningful variables, was given 1 point, and a receiver-operating characteristic curve with a cutoff value (> 1) in a 5-point scoring system (0-4 points) was analyzed to evaluate the accuracy of differentiation between HGA and SFTS. The system showed 94.5% sensitivity, 92.6% specificity, and an area under the receiver-operating characteristic curve of 0.971 (0.949-0.9). Where HGA and SFTS are endemic, the scoring system based on these four parameters such as sex, neutrophil count, activated partial thromboplastin time, and C-reactive protein concentration will facilitate the differential diagnosis of HGA and SFTS in the emergency room in patients with suspected tick-borne infectious diseases.