Investigation of the Efficacy of Benzylidene-3-methyl-2-thioxothiazolidin-4-one Analogs with Antioxidant Activities on the Inhibition of Mushroom and Mammal Tyrosinases.

Based on the fact that substances with a ß-phenyl-α,ß-unsaturated carbonyl (PUSC) motif confer strong tyrosinase inhibitory activity, benzylidene-3-methyl-2-thioxothiazolidin-4-one (BMTTZD) analogs 1-8 were prepared as potential tyrosinase inhibitors. Four analogs (1-3 and 5) inhibited mushroom tyrosinase strongly. Especially, analog 3 showed an inhibitory effect that was 220 and 22 times more powerful than kojic acid in the presence of l-tyrosine and l-dopa, respectively. A kinetic study utilizing mushroom tyrosinase showed that analogs 1 and 3 competitively inhibited tyrosinase, whereas analogs 2 and 5 inhibited tyrosinase in a mixed manner. A docking simulation study indicated that analogs 2 and 5 could bind to both the tyrosinase active and allosteric sites with high binding affinities. In cell-based experiments using B16F10 cells, analogs 1, 3, and 5 effectively inhibited melanin production; their anti-melanogenic effects were attributed to their ability to inhibit intracellular tyrosinase activity. Moreover, analogs 1, 3, and 5 inhibited in situ B16F10 cellular tyrosinase activity. In three antioxidant experiments, analogs 2 and 3 exhibited strong antioxidant efficacy, similar to that of the positive controls. These results suggest that the BMTTZD analogs are promising tyrosinase inhibitors for the treatment of hyperpigmentation-related disorders.

Trends of Gaps Between Health-Adjusted Life Expectancy and Life Expectancy at the Regional Level in Korea Using a Group-Based Multi-Trajectory Modeling Approach (2008-2019).

BACKGROUND: Health-adjusted life expectancy (HALE) is an indicator of the average lifespan in good health. Through this study, we aimed to identify regional disparities in the gap between HALE and life expectancy, considering the trends that have changed over time in Korea. METHODS: We employed a group-based multi-trajectory modeling approach to capture trends in the gap between HALE and life expectancy at the regional level from 2008 to 2019. HALE was calculated using incidence-based "years lived with disability." This methodology was also employed in the Korean National Burden of Disease Study. RESULTS: Based on five different information criteria, the most fitted number of trajectory groups was seven, with at least 11 regions in each group. Among the seven groups, one had an exceptionally large gap between HALE and life expectancy compared to that of the others. This group was assigned to 17 regions, of which six were metropolitan cities. CONCLUSION: Based on the results of this study, we identified regions in which health levels have deteriorated over time, particularly within specific areas of metropolitan cities. These findings can be used to design comprehensive policy interventions for community health promotion and urban regeneration projects in the future.

Establishment of a Dataset for the Traditional Korean Medicine Examination in Healthy Adults.

We established a protocol for the traditional Korean medicine examination (KME) and methodically gathered data following this protocol. Potential indicators for KME were extracted through a literature review; the first KME protocol was developed based on three rounds of expert opinions. The first KME protocol's feasibility was confirmed, and data were collected over four years from traditional Korean medicine (KM) hospitals, focusing on healthy adults, using the final KME protocol. A literature review identified 175 potential core indicators, condensed into 73 indicators after three rounds of expert consultation. The first KME protocol, which was categorized under questionnaires and medical examinations, was developed after the third round of expert opinions. A pilot study using the first KME protocol was conducted to ensure its validity, leading to modifications resulting in the development of the final KME protocol. Over four years, data were collected from six KM hospitals, focusing on healthy adults; we obtained a dataset comprising 11,036 healthy adults. This is the first protocol incorporating core indicators of KME in a quantitative form and systematically collecting data. Our protocol holds potential merit in evaluating predisposition to diseases or predicting diseases.

The secreted protein Amuc_1409 from Akkermansia muciniphila improves gut health through intestinal stem cell regulation.

Akkermansia muciniphila has received great attention because of its beneficial roles in gut health by regulating gut immunity, promoting intestinal epithelial development, and improving barrier integrity. However, A. muciniphila-derived functional molecules regulating gut health are not well understood. Microbiome-secreted proteins act as key arbitrators of host-microbiome crosstalk through interactions with host cells in the gut and are important for understanding host-microbiome relationships. Herein, we report the biological function of Amuc_1409, a previously uncharacterised A. muciniphila-secreted protein. Amuc_1409 increased intestinal stem cell (ISC) proliferation and regeneration in ex vivo intestinal organoids and in vivo models of radiation- or chemotherapeutic drug-induced intestinal injury and natural aging with male mice. Mechanistically, Amuc_1409 promoted E-cadherin/ß-catenin complex dissociation via interaction with E-cadherin, resulting in the activation of Wnt/ß-catenin signaling. Our results demonstrate that Amuc_1409 plays a crucial role in intestinal homeostasis by regulating ISC activity in an E-cadherin-dependent manner and is a promising biomolecule for improving and maintaining gut health.

Mesenchymal Stem Cells Reduce the Extracellular Mitochondrial DNA-Mediated TLR9 Activation in Neonatal Hyperoxia-Induced Lung Injury.

Mitochondrial DNA (mtDNA) released from dead or injured cells can activate inflammation, and mesenchymal stem cell (MSC) transplantation can reduce inflammation and injury. However, it has not been tested whether the release of mtDNA can be reduced by MSC transplantation. We hypothesized that the level of extracellular mtDNA would be increased after hyperoxia-induced lung injury but reduced after lung injury attenuation by MSC therapy in our newborn rat model. In an in vitro study using a rat lung epithelial L2 cell line, we found that the level of extracellular mtDNA was significantly increased with H2O2-induced cell death but reduced after MSC co-incubation. In an in vivo study, we confirmed that the levels of cell death, extracellular mtDNA, and inflammatory cytokines were significantly increased in hyperoxic newborn rat lungs but reduced after MSC transplantation. The levels of extracellular mtDNA were significantly and positively correlated with the levels of the inflammatory cytokines. The TLR9/MyD88/NF-κB pathway, which is activated by binding to mtDNA, was also significantly upregulated but downregulated after MSC transplantation. We found a significant positive correlation between inflammatory cytokines and extracellular mtDNA in intubated neonates. The levels of inflammatory cytokines and extracellular mtDNA changed over time in a similar pattern in transtracheal aspirate samples from intubated neonates. In conclusion, increased levels of extracellular mtDNA are associated with increased inflammation in hyperoxia-induced lung injury, and attenuation of lung inflammation by MSC therapy is associated with reduced levels of extracellular mtDNA.

Trends in Healthy Life Expectancy (HALE) and Disparities by Income and Region in Korea (2008-2020): Analysis of a Nationwide Claims Database.

BACKGROUND: Healthy life expectancy is a well-recognized indicator for establishing health policy goals used in Korea's Health Plan. This study aimed to explore Koreans' healthy life expectancy and its gender, income, and regional disparities from 2008 to 2020. METHODS: This study was conducted on the entire population covered by health insurance and medical aid program in Korea. The incidence-based "years lived with disability" for 260 disease groups by gender, income level, and region was calculated employing the methodology developed in the Korean National Burden of Disease Study, and it was used as the number of healthy years lost to calculate health-adjusted life expectancy (HALE). RESULTS: Koreans' HALE increased from 68.89 years in 2008 to 71.82 years in 2020. Although the gender disparity in HALE had been decreasing, it increased to 4.55 years in 2020. As of 2020, 5.90 years out of 8.67 years of the income disparity (Q5-Q1) in HALE were due to the disparity between Q1 and Q2, the low-income groups. Income and regional disparities in HALE exhibited an increasing trend, and these disparities were higher in men than in women. CONCLUSION: A subgroup with a low health level was identified through the HALE results, and it was confirmed that improving the health level of this population can reduce health inequalities and improve health at the national level. Further exploration of the HALE calculation methodology may help in the development of effective policies such as prioritizing interventions for health risk factors.

Microglial inhibition alleviates alpha-synuclein propagation and neurodegeneration in Parkinson's disease mouse model.

The accumulation of alpha-synuclein (αSyn) is widely recognized as the main pathological process in Parkinson's disease (PD). Additionally, neuroinflammation is considered to be one of the contributing mechanisms in the development of PD. In light of this, it is hypothesized that the reactive microglia exacerbate the propagation of αSyn and neurodegeneration, while the inhibition of microglial activity may mitigate these effects. To test this hypothesis, αSyn preformed fibrils (PFF)-injected PD mouse model was employed. Co-injection of lipopolysaccharide (LPS) and PFF was performed to investigate if microglial reactivity intensified αSyn propagation and neurodegeneration. Additionally, oral administration of PLX5622, a microglial inhibitor that targets the colony-stimulating factor 1 receptor, was given for two weeks before and after PFF injection each to explore if microglial inhibition could prevent or reduce αSyn pathology. Intrastriatal co-injection of LPS and PFF resulted in increased microglial reactivity, αSyn accumulation, and neurodegeneration compared to PFF injection alone. However, treatment with PLX5622 significantly suppressed microglial reactivity, reduced αSyn pathology, and alleviated dopaminergic neuron degeneration in the PD mouse model injected with PFF. Based on these findings, it is evident that microglial reactivity plays a crucial role in the progression of αSyn pathology and neurodegeneration in PD. Furthermore, the results suggest that microglial inhibition may hold promise as a therapeutic strategy to delay the progression of αSyn pathology in PD.

Vaccination and the risk of post-acute sequelae after COVID-19 in the Omicron-predominant period.

OBJECTIVES: To assess the association of primary and third doses of vaccination with the risk of post-acute sequelae of COVID-19. METHODS: This retrospective cohort study utilized a combined database of nationwide health care claims data, COVID-19 patient registry, and vaccination records from South Korea. Individuals diagnosed with COVID-19 in the Omicron variant-dominant period of January-March 2022 were tracked for 30-120 days post-infection. The exposure of interest was the receipt of primary and third doses of the SARS-CoV-2 vaccine. The occurrence of 26 specific conditions in eight domains was compared using Cox regression with inverse probability of treatment weighting. RESULTS: This study included 394 773 unvaccinated individuals and 7 604 081 individuals receiving ≥2 doses of vaccine. Compared with unvaccinated individuals, vaccination with at least two doses was associated with a reduced risk (adjusted hazard ratio; 95% CI) of several conditions, including ischaemic heart disease (0.73; 0.57-0.94), heart failure (0.55; 0.48-0.63), cardiac dysrhythmia (0.72; 0.61-0.85), cardiac arrest (0.41; 0.33-0.51), pulmonary embolism (0.66; 0.52-0.84), venous thromboembolism (0.54; 0.44-0.66), acute renal failure (0.56; 0.46-0.67), new dialysis (0.45; 0.34-0.59), chronic obstructive pulmonary disease (0.74; 0.65-0.84), acute pancreatitis (0.64; 0.51-0.80), and diabetes (0.82; 0.71-0.95). The risks of heart failure, cardiac dysrhythmias, cardiac arrest, pulmonary embolism, and new dialysis were lower in those who were vaccinated with three doses compared with those who were vaccinated with two doses. DISCUSSION: Vaccination was associated with a decreased risk of post-acute sequelae of COVID-19, suggesting its potential role in mitigating the indirect impacts of COVID-19.

Measuring the Burden of Disease in Korea Using Disability-Adjusted Life Years (2008-2020).

BACKGROUND: The measurement of health levels and monitoring of characteristics and trends among populations and subgroups are essential for informing evidence-based policy decisions. This study aimed to examine the burden of disease in Korea for both the total population and subgroups in 2020, as well as analyze changes in disease burden from 2008 to 2020. METHODS: We employed the methodology developed in the Korean National Burden of Disease and Injuries Study to calculate disability-adjusted life years (DALYs) by sex, causes, region, and income level from 2008 to 2020. DALYs were derived by combining years of life lost and years lived with disability. RESULTS: In 2020, the burden of disease for the Korean population was estimated to be 25,439 DALYs per 100,000 population, reflecting a 13.8% increase since 2008. The leading causes of DALYs were diabetes mellitus, followed by low back pain and ischemic stroke. A sex-specific gap reversal was observed, with the disease burden for men surpassing that of women starting in 2017. Furthermore, variations in disease burden were identified across 250 regions and income quintiles. CONCLUSION: It is imperative to establish appropriate health policies that prioritize the diseases with significantly increasing burdens and subgroups experiencing high disease burdens. The findings of this study are expected to serve as a foundation for developing healthcare policies aimed at improving the health levels of Koreans and achieving health equity.

Progranulin haploinsufficiency mediates cytoplasmic TDP-43 aggregation with lysosomal abnormalities in human microglia.

BACKGROUND: Progranulin (PGRN) haploinsufficiency due to progranulin gene (GRN) variants can cause frontotemporal dementia (FTD) with aberrant TAR DNA-binding protein 43 (TDP-43) accumulation. Despite microglial burden with TDP-43-related pathophysiology, direct microglial TDP-43 pathology has not been clarified yet, only emphasized in neuronal pathology. Thus, the objective of this study was to investigate TDP-43 pathology in microglia of patients with PGRN haploinsufficiency. METHODS: To design a human microglial cell model with PGRN haploinsufficiency, monocyte-derived microglia (iMGs) were generated from FTD-GRN patients carrying pathogenic or likely pathogenic variants (p.M1? and p.W147*) and three healthy controls. RESULTS: iMGs from FTD-GRN patients with PGRN deficiency exhibited severe neuroinflammation phenotype and failure to maintain their homeostatic molecular signatures, along with impaired phagocytosis. In FTD-GRN patients-derived iMGs, significant cytoplasmic TDP-43 aggregation and accumulation of lipid droplets with profound lysosomal abnormalities were observed. These pathomechanisms were mediated by complement C1q activation and upregulation of pro-inflammatory cytokines. CONCLUSIONS: Our study provides considerable cellular and molecular evidence that loss-of-function variants of GRN in human microglia can cause microglial dysfunction with abnormal TDP-43 aggregation induced by inflammatory milieu as well as the impaired lysosome. Elucidating the role of microglial TDP-43 pathology in intensifying neuroinflammation in individuals with FTD due to PGRN deficiency and examining consequential effects on microglial dysfunction might yield novel insights into the mechanisms underlying FTD and neurodegenerative disorders.

Association of Muscle Mass Loss with Diabetes Development in Liver Transplantation Recipients.

BACKGRUOUND: Post-transplant diabetes mellitus (PTDM) is one of the most significant complications after transplantation. Patients with end-stage liver diseases requiring transplantation are prone to sarcopenia, but the association between sarcopenia and PTDM remains to be elucidated. We aimed to investigate the effect of postoperative muscle mass loss on PTDM development. METHODS: A total of 500 patients who underwent liver transplantation at a tertiary care hospital between 2005 and 2020 were included. Skeletal muscle area at the level of the L3-L5 vertebrae was measured using computed tomography scans performed before and 1 year after the transplantation. The associations between the change in the muscle area after the transplantation and the incidence of PTDM was investigated using a Cox proportional hazard model. RESULTS: During the follow-up period (median, 4.9 years), PTDM occurred in 165 patients (33%). The muscle mass loss was greater in patients who developed PTDM than in those without PTDM. Muscle depletion significantly increased risk of developing PTDM after adjustment for other confounding factors (hazard ratio, 1.50; 95% confidence interval, 1.23 to 1.84; P=0.001). Of the 357 subjects who had muscle mass loss, 124 (34.7%) developed PTDM, whereas of the 143 patients in the muscle mass maintenance group, 41 (28.7%) developed PTDM. The cumulative incidence of PTDM was significantly higher in patients with muscle loss than in patients without muscle loss (P=0.034). CONCLUSION: Muscle depletion after liver transplantation is associated with increased risk of PTDM development.

Continued JAK inhibitor treatment on the risk of recurrent herpes zoster reactivation in patients with immune-mediated inflammatory diseases: A nationwide population-based study in South Korea.

BACKGROUND: To investigate the risk of recurrent herpes zoster (HZ) reactivation under continued Janus kinase inhibitor (JAKi) therapy in patients with immune-mediated inflammatory diseases (IMID) who developed HZ reactivation. METHODS: Data from the Korean Health Insurance Review and Assessment Service (HIRA) of patients with rheumatoid arthritis (RA) or ulcerative colitis (UC) gathered from 2007 to 2021 were analyzed. RESULTS: A total of 3947 (RA 3540, UC 407) receiving JAKi were included. After median 0.95 years (IQR, 0.93-2.58) of therapy, 611 (15.5%) patients developed HZ reactivation (incidence rate: 8.38/100 person-years [PY]). After excluding 151 patients with lack of data after HZ reactivation, 460 patients (JAKi continuation group, n = 386 [83.9%]; JAKi discontinuation group, n = 74 [16.1%]) were analyzed for the risk of subsequent recurrent HZ reactivation. During further follow-up of median 1.11 years (IQR, 0.53-1.91), 36 (9.3%) and 6 (8.1%) patients in the JAKi continuation group and JAKi discontinuation group experienced a recurrence of HZ, respectively. The incidence rate of subsequent recurrent HZ reactivation was not significantly different between the two groups (5.3/100 vs. 5.9/100 PY; P = 0.52). After adjusting for age, sex, usage of corticosteroids, and antiviral agents, continued use of JAKi was not a significant risk factor for subsequent HZ reactivation (adjusted hazard ratio, 0.71 [CI, 0.29-1.72], P = 0.45). CONCLUSION: In this nationwide population-based study on patients with RA or UC, continued use of JAKi was not associated with a significant risk of subsequent recurrent HZ reactivation. JAKi therapy may be maintained in patients with IMID even after HZ reactivation.

A Survey of Perspectives on Telemedicine for Patients With Parkinson's Disease.

OBJECTIVE: Parkinson's disease (PD) patients often find it difficult to visit hospitals because of motor symptoms, distance to the hospital, or the absence of caregivers. Telemedicine is one way to solve this problem. METHODS: We surveyed 554 PD patients from eight university hospitals in Korea. The questionnaire consisted of the clinical characteristics of the participants, possible teleconferencing. METHODS: , and preferences for telemedicine. RESULTS: A total of 385 patients (70%) expressed interest in receiving telemedicine. Among them, 174 preferred telemedicine whereas 211 preferred in-person visits. The longer the duration of disease, and the longer the time required to visit the hospital, the more patients were interested in receiving telemedicine. CONCLUSION: This is the first study on PD patients' preferences regarding telemedicine in Korea. Although the majority of patients with PD have a positive view of telemedicine, their interest in receiving telemedicine depends on their different circumstances.

Comparative Olfactory Profiles in Parkinson's Disease and Drug-Induced Parkinsonism.

OBJECTIVE: Drug-induced parkinsonism (DIP) is a frequently encountered diagnostic possibility when considering Parkinson's disease (PD). While olfactory dysfunction is a common clinical feature in PD, the comparison of olfactory function between the two conditions remains insufficient. This study aimed to compare olfactory function, including threshold, discrimination, and identification (TDI) profiles, between PD and DIP. METHODS: Consecutive patients with drug-naïve PD (n = 78) or DIP (n = 31) confirmed through dopamine transporter imaging were enrolled in this study. The YSK olfactory function (YOF) test, composed of TDI domains culturally familiar odorants to Koreans, was administered to all patients. RESULTS: In the study population, patients with DIP were significantly older than patients with PD. Over 70% of patients in each group had hyposmia or anosmia, and there was no significant difference in the occurrence of olfactory dysfunction between the two groups. In addition, there were no differences in the total YOF score and threshold score between the two groups. Meanwhile, the PD group had a significantly lower discrimination and identification score than the DIP group after adjusting for age, sex, the existence of diabetes, disease duration, and cognitive function. CONCLUSION: This study demonstrated that detailed olfactory profiles are different in PD and DIP, even though olfactory dysfunction can be observed in both conditions.

Febuxostat dose requirement according to renal function in patients who achieve target serum urate levels: A retrospective cohort study.

OBJECTIVES: To determine the febuxostat dose requirement according to renal function in patients who achieve target serum urate (SU) levels. METHODS: Of 3153 gout patients who underwent febuxostat treatment, 873 patients with an initial SU level>6mg/dL were included and categorized by the estimated glomerular filtration rate: normal, chronic kidney disease (CKD) stage 3, and stages 4-5. Ninety-five patients with insufficient follow-up were further excluded. The dose of febuxostat in patients who achieved the SU target (< 6mg/dL) was defined as the average daily dosage at the time of SU target achievement. RESULTS: The cohort of 778 gout patients had a median age of 52.0 years (IQR, 41.0-63.0) and comprised 711 (91.4%) men. The mean SU at febuxostat initiation was higher in the CKD 4-5 (9.6 [± 3.1] mg/dL) than in the other groups (CKD 3, 8.7 [± 1.7]; normal, 8.4 [± 1.7]; P<0.001). Patients achieved target SU at a median of 4.0 (1.9-9.6) months and in those who achieved target SU, the dose of febuxostat at the time of SU target achievement was significantly lower in the CKD 4-5 group (50.0 [± 16.5] mg) than in the other groups (vs. CKD stage 3, 60.0 [± 19.5] mg; P<0.01, vs. normal, 60.0 [± 19.8] mg; P<0.01). Furthermore, CKD stage 4-5 had a negative correlation with the febuxostat dose requirement (Beta: -2.334, P<0.05). CONCLUSION: Among patients who achieved SU target, those with severely decreased renal function (CKD 4-5) required a lower febuxostat dose to achieve the target SU level compared to patients with normal or mild renal impairment.

Caregiver Burden of Patients With Huntington's Disease in South Korea.

OBJECTIVE: This is the first prospective cohort study of Huntington's disease (HD) in Korea. This study aimed to investigate the caregiver burden in relation to the characteristics of patients and caregivers. METHODS: From August 2020 to February 2022, we enrolled patients with HD from 13 university hospitals in Korea. We used the 12-item Zarit Burden Interview (ZBI-12) to evaluate the caregiver burden. We evaluated the clinical associations of the ZBI-12 scores by linear regression analysis and investigated the differences between the low- and high-burden groups. RESULTS: Sixty-five patients with HD and 45 caregivers were enrolled in this cohort study. The average age at onset of motor symptoms was 49.3 ± 12.3 years, with an average cytosine-adenine-guanine (CAG)n of 42.9 ± 4.0 (38-65). The median ZBI-12 score among our caregivers was 17.6 ± 14.2. A higher caregiver burden was associated with a more severe Shoulson-Fahn stage (p = 0.038) of the patients. A higher ZBI-12 score was also associated with lower independence scale (B = -0.154, p = 0.006) and functional capacity (B = -1.082, p = 0.002) scores of patients. The caregiving duration was longer in the high- than in the low-burden group. Caregivers' demographics, blood relation, and marital and social status did not affect the burden significantly. CONCLUSION: HD patients' neurological status exerts an enormous impact on the caregiver burden regardless of the demographic or social status of the caregiver. This study emphasizes the need to establish an optimal support system for families dealing with HD in Korea. A future longitudinal analysis could help us understand how disease progression aggravates the caregiver burden throughout the entire disease course.

Comparative safety analysis of mRNA and adenoviral vector COVID-19 vaccines: a nationwide cohort study using an emulated target trial approach.

OBJECTIVE: This nationwide cohort study compared the incidence of adverse events of special interest (AESIs) between adenoviral vector-based (ChAdOx1) and mRNA-based (BNT162b2 or mRNA-1273) coronavirus disease 2019 (COVID-19) vaccines. METHODS: A targeted trial emulation study was conducted using data from the National Health Insurance Service database. Vaccinees aged 18-85 years who had received at least one dose of ChAdOx1 or an mRNA-based vaccine were identified. The 42-day risks of AESIs were calculated. RESULTS: A total of 1 767 539 ChAdOx1 vaccinees were matched exactly with mRNA vaccinees according to their risk factors. The 42-day risks of adverse events were low (∼0 to 176 events per 100 000 persons in both vaccine groups), and the incidence rates of AESIs were comparable between the two platforms, except for a higher occurrence of acute cardiac injury (incidence rate ratio [IRR], 1.22; 95% CI, 1.10-1.35), myocarditis or pericarditis (IRR, 2.14; 95% CI, 1.14-4.04), and arrhythmia (IRR, 1.46; 95% CI, 1.24-1.71) in mRNA vaccinees. The incidence of Guillain-Barré syndrome (IRR, 0.20; 95% CI, 0.06-0.69), vasovagal syncope (IRR, 0.77; 95% CI, 0.62-0.97), radiculopathy (IRR = 0.59, 95% CI, 0.41-0.84), and aseptic arthritis (IRR, 0.81; 95% CI, 0.70-0.93) was significantly lower in mRNA-based vaccinees compared with ChAdOx1 vaccinees. DISCUSSION: A remarkable platform-dependent difference was observed in the safety profiles of COVID-19 vaccines, particularly for myocarditis or pericarditis and Guillain-Barré syndrome. However, the overall risk of AESIs was low for both vaccine platforms.

Risk of Severe COVID-19 and Protective Effectiveness of Vaccination Among Solid Organ Transplant Recipients.

BACKGROUND: Solid organ transplant recipients (SOTRs) are at higher risk for severe infection. However, the risk for severe COVID-19 and vaccine effectiveness among SOTRs remain unclear. METHODS: This retrospective study used a nationwide health care claims database and COVID-19 registry from the Republic of Korea (2020 to 2022). Adult SOTRs diagnosed with COVID-19 were matched with up to 4 non-SOTR COVID-19 patients by propensity score. Severe COVID-19 was defined as treatment with high-flow nasal cannulae, mechanical ventilation, or extracorporeal membrane oxygenation. RESULTS: Among 6783 SOTRs with COVID-19, severe COVID-19 was reported with the highest rate in lung transplant recipients (13.16%), followed by the heart (6.30%), kidney (3.90%), and liver (2.40%). SOTRs had a higher risk of severe COVID-19 compared to non-SOTRs, and lung transplant recipients showed the highest risk (adjusted odds ratio, 18.14; 95% confidence interval [CI], 8.53-38.58). Vaccine effectiveness against severe disease among SOTRs was 47% (95% CI, 18%-65%), 64% (95% CI, 49%-75%), and 64% (95% CI, 29%-81%) for 2, 3, and 4 doses, respectively. CONCLUSIONS: SOTRs are at significantly higher risk for severe COVID-19 compared to non-SOTRs. Vaccination is effective in preventing the progression to severe COVID-19. Efforts should be made to improve vaccine uptake among SOTRs, while additional protective measures should be developed.