During the coronavirus disease 2019 (COVID-19) pandemic, conclusively evaluating possible associations between COVID-19 vaccines and potential adverse events was of critical importance. The National Academy of Medicine of Korea established the COVID-19 Vaccine Safety Research Center (CoVaSC) with support from the Korea Disease Control and Prevention Agency to investigate the scientific relationship between COVID-19 vaccines and suspected adverse events. Although determining whether the COVID-19 vaccine was responsible for any suspected adverse event necessitated a systematic approach, traditional causal inference theories, such as Hill's criteria, encountered certain limitations and criticisms. To facilitate a systematic and evidence-based evaluation, the United States Institute of Medicine, at the request of the Centers for Disease Control and Prevention, offered a detailed causality assessment framework in 2012, which was updated in the recent report by the National Academies of Sciences, Engineering, and Medicine (NASEM) in 2024.This framework, based on a weight-of-evidence approach, allows the independent evaluation of both epidemiological and mechanistic evidence, culminating in a comprehensive conclusion about causality. Epidemiological evidence derived from population studies is categorized into four levels—high, moderate, limited, or insufficient—while mechanistic evidence, primarily from biological and clinical studies in animals and individuals, is classified as strong, intermediate, weak, or lacking. The committee then synthesizes these two types of evidence to draw a conclusion about the causal relationship, which can be described as “convincingly supports” (“evidence established” in the 2024 NASEM report), “favors acceptance,” “favors rejection,” or “inadequate to accept or reject.” The CoVaSC has established an independent committee to conduct causality assessments using the weightof-evidence framework, specifically for evaluating the causality of adverse events associated with COVID-19 vaccines. The aim of this study is to provide an overview of the weight-ofevidence framework and to detail the considerations involved in its practical application in the CoVaSC.

The COVID-19 Vaccine Safety Research Committee (CoVaSC) was established in November 2021 to address the growing need for independent, in-depth scientific evidence on adverse events (AEs) following coronavirus disease 2019 (COVID-19) vaccination. This initiative was requested by the Korea Disease Control and Prevention Agency and led by the National Academy of Medicine of Korea. In September 2022, the COVID-19 Vaccine Safety Research Center was established, strengthening CoVaSC’s initiatives. The center has conducted various studies on the safety of COVID-19 vaccines. During CoVaSC’s second research year, from September 29, 2022 to July 19, 2023, the center was restructured into 4 departments: Epidemiological Research, Clinical Research, Communication & Education, and International Cooperation & Policy Research. Its main activities include (1) managing CoVaSC and the COVID-19 Vaccine Safety Research Center, (2) surveying domestic and international trends in AE causality investigation, (3) assessing AEs following COVID-19 vaccination, (4) fostering international collaboration and policy research, and (5) organizing regular fora and training sessions for the public and clinicians. Causality assessments have been conducted for 27 diseases, and independent research has been conducted after organizing ad hoc committees comprising both epidemiologists and clinical experts on each AE of interest. The research process included protocol development, data analysis, interpretation of results, and causality assessment. These research outcomes have been shared transparently with the public and healthcare experts through various fora. The COVID-19 Vaccine Safety Research Center plans to continue strengthening and expanding its research activities to provide reliable, high-quality safety information to the public.

With the introduction of coronavirus disease 2019 (COVID-19) vaccines, the Korea Disease Control and Prevention Agency (KDCA) commissioned the National Academy of Medicine of Korea to gather experts to independently assess post-vaccination adverse events. Accordingly, the COVID-19 Vaccine Safety Research Committee (CoVaSC) was launched in November 2021 to perform safety studies and establish evidence for policy guidance. The CoVaSC established 3 committees for epidemiology, clinical research, and communication. The CoVaSC mainly utilizes pseudonymized data linking KDCA’s COVID-19 vaccination data and the National Health Insurance Service’s claims data. The CoVaSC’s 5-step research process involves defining the target diseases and organizing ad-hoc committees, developing research protocols, performing analyses, assessing causal relationships, and announcing research findings and utilizing them to guide compensation policies. As of 2022, the CoVaSC completed this research process for 15 adverse events. The CoVaSC launched the COVID-19 Vaccine Safety Research Center in September 2022 and has been reorganized into 4 divisions to promote research including international collaborative studies, long-/short-term follow-up studies, and education programs. Through these enhancements, the CoVaSC will continue to swiftly provide scientific evidence for COVID-19 vaccine research and compensation and may serve as a model for preparing for future epidemics of new diseases.

Background and objectives: Athlete’s heart is characterized by structural cardiac changes, including enlargement and hypertrophy. However, exercise-induced cardiac electrical remodeling is not well known in Asian athletes. We sought to evaluate the association between vigorous exercise and the development of abnormal late potential on signal-averaged electrocardiogram (SAECG).Method: We analyzed 48 Korean professional soccer players and 71 healthy sedentary controls who underwent SAECG and transthoracic echocardiography at Kyung Hee University Hospital. An SAECG was considered abnormal (positive for ventricular late potential) when any one of the three following criteria was met: filtered QRS dura‑ tion > 114 ms, root-mean-square voltage in the terminal 40 ms < 20 uV, or a voltage < 40 uV for more than 38 ms. Results: Fragmented QRS was more commonly found in athletes (1.4% vs. 10.4%). Athletes demonstrated signifi‑ cantly higher proportion of filtered QRS duration > 114 ms (7.0% vs. 22.9%, P = 0.013) and lower terminal QRS rootmean-square voltage < 20 uV (5.6% vs. 20.8%, P = 0.012). Ventricular late potential on SAECG was significantly more frequent in athletes (15.5% vs. 35.4%, P = 0.012). Regarding echocardiographic parameters, the athletes had larger cardiac chamber size; however, these differences became non-significant after adjustment for body surface area, except left ventricular mass index (65.7 ± 12.7 g/m2 vs. 84.7 ± 17.7 g/m2 , P < 0.001). Conclusion Abnormal SAECG findings were significantly more common in athletes than in controls. Further study is needed to determine the clinical impact of these abnormal SAECGs in athletes and cardiac outcomes in the long term.

Background and objectives: Athlete’s heart is characterized by structural cardiac changes, including enlargement and hypertrophy. However, exercise-induced cardiac electrical remodeling is not well known in Asian athletes. We sought to evaluate the association between vigorous exercise and the development of abnormal late potential on signal-averaged electrocardiogram (SAECG).Method: We analyzed 48 Korean professional soccer players and 71 healthy sedentary controls who underwent SAECG and transthoracic echocardiography at Kyung Hee University Hospital. An SAECG was considered abnormal (positive for ventricular late potential) when any one of the three following criteria was met: filtered QRS dura‑ tion > 114 ms, root-mean-square voltage in the terminal 40 ms < 20 uV, or a voltage < 40 uV for more than 38 ms. Results: Fragmented QRS was more commonly found in athletes (1.4% vs. 10.4%). Athletes demonstrated signifi‑ cantly higher proportion of filtered QRS duration > 114 ms (7.0% vs. 22.9%, P = 0.013) and lower terminal QRS rootmean-square voltage < 20 uV (5.6% vs. 20.8%, P = 0.012). Ventricular late potential on SAECG was significantly more frequent in athletes (15.5% vs. 35.4%, P = 0.012). Regarding echocardiographic parameters, the athletes had larger cardiac chamber size; however, these differences became non-significant after adjustment for body surface area, except left ventricular mass index (65.7 ± 12.7 g/m2 vs. 84.7 ± 17.7 g/m2 , P < 0.001). Conclusion Abnormal SAECG findings were significantly more common in athletes than in controls. Further study is needed to determine the clinical impact of these abnormal SAECGs in athletes and cardiac outcomes in the long term.

Objective: : Endovascular treatment of intracranial aneurysms is challenging in case of wide-necked aneurysms because coils are prone to herniate into the parent artery, causing thromboembolic events or vessel occlusion. This study aims to compare long-term angiographic results of wide-necked aneurysms treated by stent-assisted, double-microcatheter, or single-microcatheter groups. Methods: : Between January 2003 and October 2016, 108 aneurysms that were treated with endovascular coil embolization with a neck size wider than 4 mm and a follow-up period of more than 3 years were selected. We performed coil embolization with singlemicrocatheter, double-microcatheter, and stent-assisted techniques. Angiographic results were evaluated using the Raymond-Roy occlusion classification (RROC). All medical and angiographic records were reviewed retrospectively. Results: : Clinical and angiographic analyses were conducted in 108 wide-necked aneurysms. The immediate post-procedural results revealed RROC class I (complete occlusion) in 66 cases (61.1%), class II (residual neck) in 36 cases (33.3%), and class III (residual sac) in six cases (5.6%). The final follow-up results revealed class I in 48 cases (44.4%), class II in 49 cases (45.4%), and class III in 11 cases (10.2%). Of a total of 45 (41.6%) radiologic recurrences, there were 21 cases (19.4%) of major recurrence that required additional treatment, and 24 cases (22.2%) of minor recurrence. The final follow-up angiographic results showed statistically significant differences between the stent-assisted group and the others (p<0.01). Conclusion : Long-term follow-up angiography demonstrated that the stent-assisted technique had a better complete occlusion rate than the other two techniques.

Objective: : Endovascular treatment of intracranial aneurysms is challenging in case of wide-necked aneurysms because coils are prone to herniate into the parent artery, causing thromboembolic events or vessel occlusion. This study aims to compare long-term angiographic results of wide-necked aneurysms treated by stent-assisted, double-microcatheter, or single-microcatheter groups. Methods: : Between January 2003 and October 2016, 108 aneurysms that were treated with endovascular coil embolization with a neck size wider than 4 mm and a follow-up period of more than 3 years were selected. We performed coil embolization with singlemicrocatheter, double-microcatheter, and stent-assisted techniques. Angiographic results were evaluated using the Raymond-Roy occlusion classification (RROC). All medical and angiographic records were reviewed retrospectively. Results: : Clinical and angiographic analyses were conducted in 108 wide-necked aneurysms. The immediate post-procedural results revealed RROC class I (complete occlusion) in 66 cases (61.1%), class II (residual neck) in 36 cases (33.3%), and class III (residual sac) in six cases (5.6%). The final follow-up results revealed class I in 48 cases (44.4%), class II in 49 cases (45.4%), and class III in 11 cases (10.2%). Of a total of 45 (41.6%) radiologic recurrences, there were 21 cases (19.4%) of major recurrence that required additional treatment, and 24 cases (22.2%) of minor recurrence. The final follow-up angiographic results showed statistically significant differences between the stent-assisted group and the others (p<0.01). Conclusion : Long-term follow-up angiography demonstrated that the stent-assisted technique had a better complete occlusion rate than the other two techniques.

Objective: To investigate the predictive value of intraplaque neovascularization (IPN) for cardiovascular outcomes. Materials and Methods: We evaluated 217 patients with coronary artery disease (CAD) (158 men; mean age, 68 ± 10 years) with a maximal carotid plaque thickness ≥ 1.5 mm for the presence of IPN using contrast-enhanced ultrasonography. We compared patients with (n = 116) and without (n = 101) IPN during the follow-up period and investigated the predictors of major adverse cardiovascular events (MACE), including cardiac death, myocardial infarction, coronary artery revascularization, and transient ischemic accident/stroke. Results: During the mean follow-up period of 995 ± 610 days, the MACE rate was 6% (13/217). Patients with IPN had a higher maximal thickness than those without IPN (2.86 ± 1.01 vs. 2.61 ± 0.84 mm, p = 0.046). Common carotid artery-peak systolic velocity, left ventricular mass index (LVMI), and ventricular-vascular coupling index were significantly correlated with MACE. However, on multivariate Cox regression analysis, increased LVMI was independently related to MACE (p < 0.05). The presence of IPN could not predict MACE. Conclusion The presence of IPN was related to a higher plaque thickness but could not predict cardiovascular outcomes better than conventional clinical factors in patients with CAD.

BACKGROUND: The masseter nerve is a useful donor nerve for reconstruction in patients with established facial palsy, with numerous advantages including low morbidity, a strong motor impulse, high reliability, and fast reinnervation. In this study, we assessed the results of masseter nerve–innervated free gracilis muscle transfer in established facial palsy patients. METHODS: Ten patients with facial palsy who received treatment from January 2015 to January 2017 were enrolled in this study. Three patients received masseter nerve–only free gracilis transfer, and seven received double-innervated free gracilis transfer (masseter nerve and a cross-face nerve graft). Patients were evaluated using the Facial Assessment by Computer Evaluation software (FACEgram) to quantify oral commissure excursion and symmetry at rest and when smiling after muscle transfer. RESULTS: The mean time between surgery and initial movement was roughly 167.7 days. A statistically significant increase in excursion at rest and when smiling was seen after muscle transfer. There was a significant increase in the distance of oral commissure excursion at rest and when smiling. A statistically significant increase was observed in symmetry when smiling. Terzis’ functional and aesthetic grading scores showed significant improvements postoperatively. CONCLUSIONS: Masseter nerve innervation is a good option with many uses in in established facial palsy patients. For some conditions, it is the first-line treatment. Free gracilis muscle transfer using the masseter nerve has excellent results with good symmetry and an effective degree of recovery.
Facial Nerve ; Facial Paralysis ; Free Tissue Flaps ; Humans ; Smiling ; Tissue Donors

BACKGROUND: The purpose of this study was to evaluate changes in nasal growth after the implementation of a preoperative nasal retainer in patients with bilateral incomplete cleft lip. METHODS: Twenty-six infants with bilateral incomplete cleft lip and cleft palate were included in the study. A preoperative nasal retainer was applied in 5 patients from the time of birth to 2.6–3.5 months before primary cheiloplasty. Twenty-one patients who were treated without a preoperative nasal retainer were placed in the control group. Standard frontal, basal, and lateral view photographs were taken 3 weeks before cheiloplasty, immediately after cheiloplasty, and at the 1- and 3-year postoperative follow-up visits. The columella and nasal growth ratio and nasolabial angle were indirectly measured using photographic anthropometry. RESULTS: The ratio of columella length to nasal tip protrusion significantly increased after the implementation of a preoperative nasal retainer compared to the control group for up to 3 years postoperatively (P<0.01 for all time points). The ratios of nasal width to facial width, nasal width to intercanthal distance, columellar width to nasal width, and the nasolabial angle, for the two groups were not significantly different at any time point. CONCLUSIONS: Implementation of a preoperative nasal retainer provided significant advantages for achieving columellar elongation for up to 3 years postoperatively. It is a simple, reasonable option for correcting nostril shape, preventing deformities, and guiding development of facial structures.
Anthropometry ; Cleft Lip* ; Cleft Palate ; Congenital Abnormalities ; Follow-Up Studies* ; Humans ; Infant ; Nose ; Parturition