Analyses of Confirmed COVID-19 Cases Among Korean Military Personnel After Mass Vaccination

Background@#The military was one of the first groups in Korea to complete mass vaccination against the coronavirus disease 2019 (COVID-19) due to their high vulnerability to COVID-19.To confirm the effect of mass vaccination, this study analyzed the patterns of confirmed cases within Korean military units. @*Methods@#From August 1 to September 15, 2021, all epidemiological data regarding confirmed COVID-19 cases in military units were reviewed. The number of confirmed cases in the units that were believed to have achieved herd immunity (i.e., ≥ 70% vaccination) was compared with the number of cases in the units that were not believed to have reached herd immunity (< 70% vaccination). Additionally, trends in the incidence rates of COVID-19 in the military and the entire Korean population were compared. @*Results@#By August 2021, 85.60% of military personnel were fully vaccinated. During the study period, a total of 174 COVID-19 cases were confirmed in the 39 units. More local transmission (herd immunity group vs. non-herd immunity group [%], 1 [0.91] vs. 39 [60.94]) and hospitalizations (12 [11.01] vs. 13 [27.08]) occurred in the units that were not believed to have achieved herd immunity. The percentage of fully vaccinated individuals among the confirmed COVID-19 cases increased over time, possibly due to the prevalence of the delta variant. Nevertheless, the incidence rate remained lower in military units than in the general Korean population. @*Conclusion@#After completing mass vaccination, the incidence rates of COVID-19 infection in the military were lower than those in the national population. New cluster infections did not occur in vaccinated units, thereby suggesting that herd immunity has been achieved in these military units. Further research is needed to determine the extent to which levels of nonpharmacological intervention can be reduced in the future.

Validation of Machine Learning Models to Predict Adverse Outcomes in Patients with COVID-19: A Prospective Pilot Study

Purpose@#We previously developed learning models for predicting the need for intensive care and oxygen among patients with coronavirus disease (COVID-19). Here, we aimed to prospectively validate the accuracy of these models. @*Materials and Methods@#Probabilities of the need for intensive care [intensive care unit (ICU) score] and oxygen (oxygen score) were calculated from information provided by hospitalized COVID-19 patients (n=44) via a web-based application. The performance of baseline scores to predict 30-day outcomes was assessed. @*Results@#Among 44 patients, 5 and 15 patients needed intensive care and oxygen, respectively. The area under the curve of ICU score and oxygen score to predict 30-day outcomes were 0.774 [95% confidence interval (CI): 0.614–0.934] and 0.728 (95% CI:0.559–0.898), respectively. The ICU scores of patients needing intensive care increased daily by 0.71 points (95% CI: 0.20–1.22) after hospitalization and by 0.85 points (95% CI: 0.36–1.35) after symptom onset, which were significantly different from those in individuals not needing intensive care (p=0.002 and <0.001, respectively). Trends in daily oxygen scores overall were not markedly different; however, when the scores were evaluated within <7 days after symptom onset, the patients needing oxygen showed a higher daily increase in oxygen scores [1.81 (95% CI: 0.48–3.14) vs. -0.28 (95% CI: 1.00–0.43), p=0.007]. @*Conclusion@#Our machine learning models showed good performance for predicting the outcomes of COVID-19 patients and could thus be useful for patient triage and monitoring.

Four Times of Relapse of Plasmodium vivax Malaria Despite Primaquine Treatment in a Patient with Impaired Cytochrome P450 2D6 Function

Plasmodium vivax exhibits dormant liver-stage parasites, called hypnozoites, which can cause relapse of malaria. The only drug currently used for eliminating hypnozoites is primaquine. The antimalarial properties of primaquine are dependent on the production of oxidized metabolites by the cytochrome P450 isoenzyme 2D6 (CYP2D6). Reduced primaquine metabolism may be related to P. vivax relapses. We describe a case of 4 episodes of recurrence of vivax malaria in a patient with decreased CYP2D6 function. The patient was 52-year-old male with body weight of 52 kg. He received total gastrectomy and splenectomy 7 months before the first episode and was under chemotherapy for the gastric cancer. The first episode occurred in March 2019 and each episode had intervals of 34, 41, and 97 days, respectively. At the first and second episodes, primaquine was administered as 15 mg for 14 days. The primaquine dose was increased with 30 mg for 14 days at the third and fourth episodes. Seven gene sequences of P. vivax were analyzed and revealed totally identical for all the 4 samples. The CYP2D6 genotype was analyzed and intermediate metabolizer phenotype with decreased function was identified.

Infectivity of Coronavirus Disease 2019: A Prospective Cohort Study in the Korean Metropolitan Area

Background@#Although several characteristics of coronavirus disease 2019 (COVID-19), an ongoing pandemic disease, have been identified, data on the infectivity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are limited. @*Methods@#This prospective cohort study was conducted to analyze the infectivity of SARSCoV-2 based on data of all patients diagnosed with COVID-19 confirmed using real-time polymerase chain reaction test from January to April 2020 in Gyeonggi-do, the largest province in Korea. @*Results@#Of the 502 patients, 298 consisting of 106 clusters with 5,909 contacts were included. Of these, 277 (93.0%) were symptomatic, and the most common symptoms were cough, fever, sputum, sore throat, and headache. A total of 94 patients (31.5%) had pneumonia, while 8 (2.7%) died during the follow-up period. The secondary attack rate (SAR) in the study population was 3.5% (204/5,909). In exposure settings, the SAR was higher in religious gathering (13.5% [95% confidence interval, 10.7–16.8%]), workplaces (8.49% [95% CI, 6.08–11.74%]), and schools (6.38% [95% CI, 3.39–11.69%]) than in health care facilities (1.92% [95% CI, 1.45–2.55%]). Sore throat at any period, dyspnea at diagnosis or any period, lower cycle threshold value in the lower respiratory tract samples, leukocytosis, and higher bilirubin levels were associated with higher infectivity of COVID-19. The presence of symptoms was not related to the infectivity. @*Conclusion@#In establishing the infection control strategies for COVID-19, the variables associated with high infectivity may be considered.

Clinical and Laboratory Factors Associated with Symptom Development in Asymptomatic COVID-19 Patients at the Time of Diagnosis

In preparation for the surge of coronavirus disease 2019 (COVID-19), it is crucial to allocate medical resources efficiently for distinguishing people who remain asymptomatic until the end of the disease. Between January 27, 2020, and April 21, 2020, 517 COVID-19 cases from 13 healthcare facilities in Gyeonggi province, Korea, were identified out of which the epidemiologic and clinical information of 66 asymptomatic patients at the time of diagnosis were analyzed retrospectively. An exposure-diagnosis interval within 7 days and abnormal aspartate aminotransferase levels were identified as characteristic symptom development in asymptomatic COVID-19 patients. If asymptomatic patients without these characteristics at the time of diagnosis could be differentiated early, more medical resources could be secured for mild or moderate cases in this COVID-19 surge.

Parsonage-Turner Syndrome Following Typhoid Vaccination

Parsonage-Turner syndrome is a rare neurological disease of varying etiology characterized by severe shoulder pain, muscle weakness, and atrophy. Mechanisms are unclear, but are thought to be genetic and immune-mediated reactions. Rarely, Parsonage-Turner syndrome occurs as a side effect of vaccination. A 20-year-old male who worked as a soldier visited the military hospital because of shoulder pain after vaccination against typhoid and was diagnosed with Parsonage-Turner syndrome based on electromyography and joint magnetic resonance imaging. Pain was controlled with a nerve block. Intravenous immunoglobulin was administered for improvement of neurologic symptoms. This case suggests that Parsonage-Turner syndrome should be considered as a side effect of vaccination. To the best of our knowledge, this is the first report of Parsonage-Turner syndrome following vaccination in Korea.

Parsonage-Turner Syndrome Following Typhoid Vaccination

Parsonage-Turner syndrome is a rare neurological disease of varying etiology characterized by severe shoulder pain, muscle weakness, and atrophy. Mechanisms are unclear, but are thought to be genetic and immune-mediated reactions. Rarely, Parsonage-Turner syndrome occurs as a side effect of vaccination. A 20-year-old male who worked as a soldier visited the military hospital because of shoulder pain after vaccination against typhoid and was diagnosed with Parsonage-Turner syndrome based on electromyography and joint magnetic resonance imaging. Pain was controlled with a nerve block. Intravenous immunoglobulin was administered for improvement of neurologic symptoms. This case suggests that Parsonage-Turner syndrome should be considered as a side effect of vaccination. To the best of our knowledge, this is the first report of Parsonage-Turner syndrome following vaccination in Korea.

Ongoing outbreak of human adenovirus-associated acute respiratory illness in the Republic of Korea military, 2013 to 2018

Background/Aims@#Human adenovirus type 55 (HAdV-55), an emerging epidemic strain, has caused several large outbreaks in the Korean military since 2014, and HAdV-associated acute respiratory illness (HAdV-ARI) has been continuously reported thereafter. @*Methods@#To evaluate the epidemiologic characteristics of HAdV-ARI in the Korean military, we analyzed respiratory virus polymerase chain reaction (RV-PCR) results, pneumonia surveillance results, and severe HAdV cases from all 14 Korean military hospitals from January 2013 to May 2018 and compared these data with nationwide RV surveillance data for the civilian population. @*Results@#A total of 14,630 RV-PCRs was performed at military hospitals. HAdV (45.4%) was the most frequently detected RV, followed by human rhinovirus (12.3%) and influenza virus (6.3%). The percentage of the military positive for HAdV was significantly greater than the percentage of civilians positive for HAdV throughout the study period, with a large outbreak occurring during the winter to spring of 2014 to 2015. The outbreak continued until the end of the study, and non-seasonal detections increased over time. The reported number of pneumonia patients also increased during the outbreak. Case fatality rate was 0.075% overall but 15.6% in patients with respiratory failure. The proportion of severe patients did not change significantly during the study period. @*Conclusions@#A large HAdV outbreak is currently ongoing in the Korean military, with a trend away from seasonality, and HAdV-55 is likely the predominant strain. Persistent efforts to control the outbreak, HAdV type-specific surveillance, and vaccine development are required.

Air Evacuation of Passengers with Potential SARS-CoV-2Infection Under the Guidelines for Appropriate Infection Control and Prevention

This report describes the air evacuation of 80 Koreans from Iran to Korea on March 19 th , 2020, with a direct transfer of passengers between airplanes in Dubai. The passengers were potentially infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) so, strict precautions were taken for the duration of the flight, and the passengers were screened before embarking from Dubai and disembarking at Incheon International Airport in Korea. Passengers with fever or symptoms of SARSCoV-2 were assessed by a quarantine doctor, and if they were suspected of being infected with SARSCoV-2, they were categorized as a “patient under investigation (PUI)”. There was 1 passenger designated as a PUI before the departure from Dubai and another designated as a PUI upon arrival into Korea. The first PUI tested negative, but the second PUI tested positive for SARS-CoV-2. All those aboard the flight (passengers, aircrew, and medical staff) were screened for SARS-CoV-2 upon arrival into Korea and completed a mandatory 14-day medical quarantine. There were no additional cases of infection.

Strategical Preparedness and Response Actions in the Healthcare System Against Coronavirus Disease 2019 according to Transmission Scenario in Korea

The dynamic nature of coronavirus disease 2019 (COVID-19) pandemic requires us to be efficient and flexible in resource utilization. The strategical preparedness and response actions of the healthcare system are the key component to contain COVID-19 and to decrease its case fatality ratio. Depending on the epidemiological situation, each medical institution should systematically share the responsibility for patient screening, disposition and treatment according to clinical severity. To overcome fast-paced COVID-19 pandemic, the government should be rapidly ready and primed for action according to the specific transmission scenario.

Clinical Course and Outcomes of 3,060 Patients with Coronavirus Disease 2019 in Korea, January–May 2020

Background@#The fatality rate of patients with coronavirus disease 2019 (COVID-19) varies among countries owing to demographics, patient comorbidities, surge capacity of healthcare systems, and the quality of medical care. We assessed the clinical outcomes of patients with COVID-19 during the first wave of the epidemic in Korea. @*Methods@#Using a modified World Health Organization clinical record form, we obtained clinical data for 3,060 patients with COVID-19 treated at 55 hospitals in Korea. Disease severity scores were defined as: 1) no limitation of daily activities; 2) limitation of daily activities but no need for supplemental oxygen; 3) supplemental oxygen via nasal cannula; 4) supplemental oxygen via facial mask; 5) non-invasive mechanical ventilation; 6) invasive mechanical ventilation; 7) multi-organ failure or extracorporeal membrane oxygenation therapy; and 8) death. Recovery was defined as a severity score of 1 or 2, or discharge and release from isolation. @*Results@#The median age of the patients was 43 years of age; 43.6% were male. The median time from illness onset to admission was 5 days. Of the patients with a disease severity score of 3–4 on admission, 65 (71.5%) of the 91 patients recovered, and 7 (7.7%) died due to illness by day 28. Of the patients with disease severity scores of 5–7, 7 (19.5%) of the 36 patients recovered, and 8 (22.2%) died due to illness by day 28. None of the 1,324 patients who were < 50 years of age died; in contrast, the fatality rate due to illness by day 28 was 0.5% (2/375), 0.9% (2/215), 5.8% (6/104), and 14.0% (7/50) for the patients aged 50–59, 60–69, 70–79, and ≥ 80 years of age, respectively. @*Conclusion@#In Korea, almost all patients of < 50 years of age with COVID-19 recovered without supplemental oxygen. In patients of ≥ 50 years of age, the fatality rate increased with age, reaching 14% in patients of ≥ 80 years of age.

Isolation of Middle East Respiratory Syndrome Coronavirus from a Patient of the 2015 Korean Outbreak

During the 2015 outbreak of Middle East respiratory syndrome coronavirus (MERS-CoV) in Korea, 186 persons were infected, resulting in 38 fatalities. We isolated MERS-CoV from the oropharyngeal sample obtained from a patient of the outbreak. Cytopathic effects showing detachment and rounding of cells were observed in Vero cell cultures 3 days after inoculation of the sample. Spherical virus particles were observed by transmission electron microscopy. Full-length genome sequence of the virus isolate was obtained and phylogenetic analyses showed that it clustered with clade B of MERS-CoV.

Clinical Progression and Cytokine Profiles of Middle East Respiratory Syndrome Coronavirus Infection

Clinical progression over time and cytokine profiles have not been well defined in patients with Middle East respiratory syndrome coronavirus (MERS-CoV) infection. We included 17 patients with laboratory-confirmed MERS-CoV during the 2015 outbreak in Korea. Clinical and laboratory parameters were collected prospectively. Serum cytokine and chemokine levels in serial serum samples were measured using enzyme-linked immunosorbent assay. All patients presented with fever. The median time to defervescence was 18 days. Nine patients required oxygen supplementation and classified into severe group. In the severe group, chest infiltrates suddenly began to worsen around day 7 of illness, and dyspnea developed at the end of the first week and became apparent in the second week. Median time from symptom onset to oxygen supplementation was 8 days. The severe group had higher neutrophil counts during week 1 than the mild group (4,500 vs. 2,200/µL, P = 0.026). In the second week of illness, the severe group had higher serum levels of IL-6 (54 vs. 4 pg/mL, P = 0.006) and CXCL-10 (2,642 vs. 382 pg/mL, P < 0.001). IFN-α response was not observed in mild cases. Our data shows that clinical condition may suddenly deteriorate around 7 days of illness and the serum levels of IL-6 and CXCL-10 was significantly elevated in MERS-CoV patients who developed severe diseases.

Middle East Respiratory Syndrome Coronavirus Superspreading Event Involving 81 Persons, Korea 2015

Since the first imported case of Middle East respiratory syndrome coronavirus (MERS-CoV) infection was reported on May 20, 2015 in Korea, there have been 186 laboratory-confirmed cases of MERS-CoV infection with 36 fatalities. Ninety-seven percent (181/186) of the cases had exposure to the health care facilities. We are reporting a superspreading event that transmitted MERS-CoV to 81 persons at a hospital emergency room (ER) during the Korean outbreak in 2015. The index case was a 35-yr-old man who had vigorous coughing while staying at the ER for 58 hr. As in severe acute respiratory syndrome outbreaks, superspreading events can cause a large outbreak of MERS in healthcare facilities with severe consequences. All healthcare facilities should establish and implement infection prevention and control measure as well as triage policies and procedures for early detection and isolation of suspected MERS-CoV cases.

Pelvic Bone Fractures Mimicking Bone Metastases in a Patient with Hepatitis B Virus-Associated Liver Cirrhosis and Hepatocellular Carcinoma

No abstract available.

Pancreatic Pseudocyst after Endoscopic Ultrasound-Guided Fine Needle Aspiration of Pancreatic Mass

Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is well known as a safe diagnostic procedure. We report the first case of pancreatic pseudocyst after EUS-FNA of the pancreatic body mass. A 60-year-old male underwent EUS-FNA for incidentally detected pancreatic solid mass which was suspected as neuroendocrine tumor. Two weeks later, the patient visited emergency room with acute abdominal pain and right upper quadrant tenderness; leukocytosis and elevated C-reactive protein, amylase, and lipase levels were noted. Computed tomography discovered newly developed 11.5x9.5 cm sized cystic mass communicating with the main pancreatic duct. Cyst fluid analysis revealed amylase level of 3,423 U/L and fluid culture isolated Streptococcus parasanguinis. The cystic mass corresponds with pancreatic pseudocyst. FNA induced main pancreatic duct injury and fluid leakage may cause it. Endoscopists who perform EUS-FNA must remember that pancreatic main duct injury can occur as one of severe complications and that it could be treated successfully with endoscopic internal drainage.

One Case of Common Bile Duct Cancer Mimicking Cystic Neoplasm of the Pancreas, Arising 9 Years after Excision of a Choledochal Cyst

A 42-years-old woman had undergone operation for cholecochal cyst with gallbladder cancer 9 years ago. Pathology revealed a polypoid mass in the gallbladder with liver infiltration as poorly differentiated adenocarcinoma. Computed tomography, magnetic resonance cholangiopancreatography, and endoscopic ultrasound showed a newly developed suspected solid nodule in the peripheral portion of cystic lesion in the pancreas head. She underwent a pylorus preserving pancreaticoduodenectomy for the suspected mucinous cystic neoplasm of the pancreas. Pathology revealed poorly differentiated adenocarcinoma. The remnant choledochal cyst had developed to cholangiocarcinoma, which mimicked cystic neoplasm of the pancreas.