Nosocomial Outbreak by Delta Variant From a Fully Vaccinated Patient

BackgroundThe potential for a nosocomial outbreak of coronavirus disease 2019 (COVID-19) from a fully vaccinated individual is largely unknown.MethodsIn October 2021, during the time when the delta variant was dominant, a nosocomial outbreak of COVID-19 occurred in two wards in a tertiary care hospital in Seoul, Korea. We performed airflow investigations and whole-genome sequencing (WGS) of the virus.ResultsThe index patient developed symptoms 1 day after admission, and was diagnosed with COVID-19 on day 4 post-admission. He was fully vaccinated (ChAdOx1 nCoV-19) 2 months before the diagnosis. Three inpatients and a caregiver in the same room, two inpatients in an adjacent room, two inpatients in rooms remote from the index room, and one nurse on the ward tested positive. Also, two resident doctors who stayed in an on-call room located on the same ward tested positive (although they had no close contact), as well as a caregiver who stayed on an adjacent ward, and a healthcare worker who had casual contact with this caregiver. Samples from five individuals were available for WGS, and all showed ≤ 1 single-nucleotide polymorphism difference. CCTV footage showed that the index case walked frequently in the corridors of two wards. An airflow study showed that the air from the corridor flowed into the resident on-call room, driven by an air circulator that was always turned on.ConclusionTransmission of severe acute respiratory syndrome coronavirus 2 from a fully vaccinated index occurred rapidly via the wards and on-call room. Care must be taken to not use equipment that can change the airflow.     

Non-alcoholic Fatty Liver Disease and COVID-19 Susceptibility and Outcomes: a Korean Nationwide Cohort

BackgroundEvidence for the association between underlying non-alcoholic fatty liver disease (NAFLD), the risk of testing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positive, and the clinical consequences of coronavirus disease 2019 (COVID-19) is controversial and scarce. We aimed to investigate the association between the presence of NAFLD and the risk of SARS-CoV-2 infectivity and COVID-19-related outcomes.MethodsWe used the population-based, nationwide cohort in South Korea linked with the general health examination records between January 1, 2018 and July 30, 2020. Data for 212,768 adults older than 20 years who underwent SARS-CoV-2 testing from January 1 to May 30, 2020, were obtained. The presence of NAFLDs was defined using three definitions, namely hepatic steatosis index (HSI), fatty liver index (FLI), and claims-based definition. The outcomes were SARS-CoV-2 test positive, COVID-19 severe illness, and related death.ResultsAmong 74,244 adults who completed the general health examination, there were 2,251 (3.0%) who were SARS-CoV-2 positive, 438 (0.6%) with severe COVID-19 illness, and 45 (0.06%) COVID-19-related deaths. After exposure-driven propensity score matching, patients with pre-existing HSI-NAFLD, FLI-NAFLD, or claims-based NAFLD had an 11–23% increased risk of SARS-CoV-2 infection (HSI-NAFLD 95% confidence interval [CI], 1–28%; FLI-NAFLD 95% CI, 2–27%; and claims-based NAFLD 95% CI, 2–31%) and a 35–41% increased risk of severe COVID-19 illness (HSI-NAFLD 95% CI, 8–83%; FLI-NAFLD 95% CI, 5–71%; and claims-based NAFLD 95% CI, 1–92%). These associations are more evident as liver fibrosis advanced (based on the BARD scoring system). Similar patterns were observed in several sensitivity analyses including the full-unmatched cohort.ConclusionPatients with pre-existing NAFLDs have a higher likelihood of testing SARS-CoV-2 positive and severe COVID-19 illness; this association was more evident in patients with NAFLD with advanced fibrosis. Our results suggest that extra attention should be given to the management of patients with NAFLD during the COVID-19 pandemic.     

Risk Factors for Severe COVID-19 in Children: A Systematic Review and Meta-Analysis

BackgroundCoronavirus disease 2019 (COVID-19) has been the most important global issue since December 2019. Although the clinical course of COVID-19 is known to be milder in children than in adults, associated hospitalizations among children have increased since the emergence of contagious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants and the achievement of a high vaccination rate in adults. Considering these global and domestic situations, we believe that risk stratification in children with COVID-19 is urgently needed for decision making regarding hospitalization priority in children infected with SARS-CoV-2 and vaccination priority against COVID-19.MethodsThis systematic review and meta-analysis was performed by comprehensively searching the PubMed, EMBASE, Scopus and KoreaMed databases through August 25, 2021. The criteria for enrollment were “severe COVID-19” as poor outcomes (intensive care unit admission, invasive mechanical ventilation, and/or death) and underlying comorbidities before SARS-CoV-2 infection.ResultsAmong 872 screened studies, 17 articles were included in the systematic review, and 10 articles were included in the meta-analysis. Neonate (risk ratio [RR], 2.69; 95% confidence interval [CI], 1.83–3.97), prematurity in young infants (RR, 2.00; 95% CI, 1.63–2.46), obesity (RR, 1.43; 95% CI, 1.24–1.64), diabetes (RR, 2.26; 95% CI, 1.95–2.62), chronic lung disease (RR, 2.62; 95% CI, 1.71–4.00), heart disease (RR, 1.82; 95% CI, 1.58–2.09), neurologic disease (RR, 1.18; 95% CI, 1.05–1.33), and immunocompromised status (RR, 1.44; 95% CI, 1.01–2.04) were significant risk factors for severe COVID-19 in children. In the subgroup analysis, age younger than 3 months (RR, 0.26; 95% CI, 0.11–0.66), asthma (RR, 1.08; 95% CI, 0.98–1.20), and neurodevelopmental disorders (RR, 0.88; 95% CI, 0.75–1.04) were not risk factors for severe COVID-19.ConclusionChildren with comorbidities such as obesity, diabetes, heart disease, chronic lung diseases other than asthma, seizure disorders, and an immunocompromised status had a high prevalence of severe COVID-19. Neonate and premature infants had a high risk of severe COVID-19. Defining the high-risk group for severe COVID-19 could help to guide hospital admission and priority for vaccination against SARS-CoV-2.     

Characteristics in Pediatric Patients with Coronavirus Disease 2019 in Korea

BackgroundBased on the reports of low prevalence and severity of pediatric severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections, the Korean government has released new SARS-CoV-2 infection response and treatment guidelines for children under the age of 12 years. The government has further directed school reopening under strict preventive measures. However, there is still considerable concern on the impact of school reopening on community transmission of Coronavirus disease 2019 (COVID-19). In the present study, we aimed to evaluate the appropriateness of these directives and the severity of SARS-CoV-2 infections in children as compared to adults using sufficient national sample data.MethodsIn the present study, we evaluated the severity of SARS-CoV-2 infection in pediatric patients as compared to adults by analyzing the length of hospital stays (LOS), medical expenses, and hospital and intensive care unit (ICU) admission rates. A multivariate linear regression analysis was carried out to examine the effects of COVID-19 patients that the characteristics on the LOS and medical expenses, and multivariate logistic regression analysis were performed to identify COVID-19 characteristics that affect hospital and ICU admission rates and to prove the low SARS-CoV-2 infection severity in pediatric patients.ResultsThe hospitalization period for children aged 0–9 was 37% shorter and that of patients aged 10–19 years was 31% shorter than those of older age groups (P < 0.001). The analysis of the medical expenses by age showed that on average, medical expenses for children were approximately 4,900 USD lower for children than for patients over 80 years of age. The linear regression analysis also showed that patients who were 0–9 years old spent 87% and those aged 10–19 118% less on medical expenses than those aged 70 and over, even after the correction of other variables (P < 0.001). The probability of hospitalization was the lowest at 10–19 years old (odds ratio [OR], 0.05; 95% confidence interval [CI], 0.03–0.09), and their ICU admission rate was also the lowest at 0.14 (OR, 0.14; 95% CI, 0.08–0.24). On the other hand, the likelihood of hospitalization and ICU admission was the highest in children aged 0–9 years, and among patients under the age of 50 years in general.ConclusionThis study demonstrated the low severity of SARS-CoV-2 infection in younger patients (0–19 years) by analyzing the LOS, medical expenses, hospital, and intensive care unit admission rates as outcome variables. As the possibility to develop severe infection of coronavirus at the age of 10–19 was the lowest, a mitigation policy is also required for middle and high school students. In addition, children with underlying diseases need to be protected from high-risk infection environments.     

Outcomes of Late-Preterm and Term Infants Born to SARS-CoV-2-Positive Mothers

With the spread of coronavirus disease 2019 (COVID-19) in Korea, the number of pregnant women infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is rapidly increasing. A shortage of negative-pressure isolation rooms for newborns makes hospital assignment more difficult for late-pregnant women with COVID-19. Among 34 infants born to SARS-CoV-2-positive mothers, 5 (14.7%) presented with respiratory distress and 1 (2.9%) presented with feeding intolerance that required specialized care. Aerosol-generating procedures were performed in one infant. Overall outcomes of 34 infants were favorable, and no infant tested positive for SARS-CoV-2. Most infants born to SARS-CoV-2-positive mothers did not need to be quarantined in a negative-pressure isolation room, and 17 (50%) mother–infant dyads were eligible for rooming-in. If negative-pressure isolation rooms are selectively used for newborns requiring aerosol-generating procedures or newborns in respiratory distress, resource availability for lower-risk cases may improve.     

Investigation of an outbreak of symptomatic SARS-CoV-2 VOC 202012/01-lineage B.1.1.7 infection in healthcare workers,Italy

ObjectivesIn December 2020, Italy began a national immunization campaign using the BNT162b2 coronavirus disease 2019 (COVID-19) mRNA vaccine, prioritizing healthcare workers (HCWs). Immune serum from vaccinated subjects seems (largely) to retain titres of neutralizing antibodies, even against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) VOC 202012/01-lineage B.1.1.7. Here, we describe an outbreak of SARS-CoV-2 lineage B.1.1.7 infection in three HCWs in a hospital setting; two of the HCWs were fully vaccinated (i.e. had received two doses).MethodsTwo physicians and one nurse working on the same shift on 20th February 2021 were involved in the outbreak. Real-time PCR, antigen tests, and serological tests for the IgG anti-spike protein of SARS-CoV-2 were performed, along with whole-genome sequencing (WGS).ResultsSARS-CoV-2 infection was confirmed in all three HCWs; all presented with mild symptoms of COVID-19. The two physicians were fully vaccinated with BNT162b2 vaccine, with the second dose administered 1 month before symptom onset. Both had high titres of IgG anti-spike antibodies at the time of diagnosis. WGS confirmed that all virus strains were VOC 202012/01-lineage B.1.1.7, suggesting a common source of exposure. Epidemiological investigation revealed that the suspected source was a SARS-CoV-2-positive patient who required endotracheal intubation due to severe COVID-19. All procedures were carried out using a full suite of personal protective equipment (PPE).ConclusionsThis mini-outbreak highlights some important issues about the efficacy of vaccines against transmission of SARS-CoV-2 variants, the high risk of exposure among HCWs, and the need for optimized implementation of PPE in hospitals. The wide circulation of VOC 202012/01 in Europe and Italy highlights the need to improve surveillance and genetic sequencing.     

Short Term Impact of Coronavirus Disease 2019 Vaccination in Children in Korea

BackgroundThe epidemiology of coronavirus disease 2019 (COVID-19) has changed continuously throughout the pandemic.MethodsWe analyzed changes in the incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection according to the age group in South Korea from February 2020 to December 2021.ResultsSince the COVID-19 pandemic, the incidence among adults aged ≥ 18 years was higher than all the other age groups in 2020; however, a shift toward younger ages occurred in June 2021. In addition, we found significant changes in epidemiology after the introduction of SARS-CoV-2 vaccines in adults aged ≥ 18 and children 12–17 years. Until recently, children were not regarded as the drive for the pandemic; however, children aged 5–11 and 0–4 years had the highest incidence among all the age groups.ConclusionTherefore, policies for clinical support for an increase in COVID-19 cases among young children and age-specific preventive measures are needed.     

TSP-based PCR for rapid identification of L and S type strains of SARS-CoV-2

BackgroundIn the initial few months of the COVID-19 pandemic, two distinct strains of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) were identified (L and S strain) based on a tightly linked SNP between two widely separated nucleotides at location 8782 (ORF1ab T8517C) and position 28,144 (ORF8: C251T, codon S84L).Materials and methodsA Type Specific Primer based one step RT-PCR (TSP-PCR) test to distinguish the L and S type strains of SARS-CoV-2 without the need for viral genome sequencing, was developed. The study also analyzed 18,221 whole genome sequences (WGS) available up to April 2020 to know the prevalence of L and S type of strains. Phylogenetic and recombination analysis of SARS-CoV-2 genome with nearest animal and human coronaviruses were analyzed using MEGA X and SimPlot version 3.5.1 software respectively.ResultsThe rapid TSP-PCR distinguished the L and S type strains of SARS-CoV-2 by amplifying a specific 326 bp and 256 bp fragment of the L and S type strain respectively. The test was used to analyzed 120 random SARS-CoV-2 positive samples from Assam, India among which 118 were found to be of L-type strains only. On analysis of 18,221 WGS, it was found that L type was the predominant strain with an overall prevalence ∼90%. However, pockets of high prevalence of S-type strains (>35%) were still in circulation in Washington region in April 2020. The study did not detect any significant recombination events between closely related coronavirus and SARS-CoV-2.ConclusionTSP-based PCR for identification of circulating strains of SARS-CoV-2, will add in rapid identification of strains of COVID-19 pandemic to understand the spread of the virus, its transmissibility and adaptation into human population. Though, the S-type strains have decreased drastically across the globe since April 2020, the role of TSP-PCR in geographical niches where such strains are still prevalent may help in rapidly distinguishing the strains and study its evolution.     

Developing and Validating Multi-Modal Models for Mortality Prediction in COVID-19 Patients: a Multi-center Retrospective Study

The unprecedented global crisis brought about by the COVID-19 pandemic has sparked numerous efforts to create predictive models for the detection and prognostication of SARS-CoV-2 infections with the goal of helping health systems allocate resources. Machine learning models, in particular, hold promise for their ability to leverage patient clinical information and medical images for prediction. However, most of the published COVID-19 prediction models thus far have little clinical utility due to methodological flaws and lack of appropriate validation. In this paper, we describe our methodology to develop and validate multi-modal models for COVID-19 mortality prediction using multi-center patient data. The models for COVID-19 mortality prediction were developed using retrospective data from Madrid, Spain (N = 2547) and were externally validated in patient cohorts from a community hospital in New Jersey, USA (N = 242) and an academic center in Seoul, Republic of Korea (N = 336). The models we developed performed differently across various clinical settings, underscoring the need for a guided strategy when employing machine learning for clinical decision-making. We demonstrated that using features from both the structured electronic health records and chest X-ray imaging data resulted in better 30-day mortality prediction performance across all three datasets (areas under the receiver operating characteristic curves: 0.85 (95% confidence interval: 0.83–0.87), 0.76 (0.70–0.82), and 0.95 (0.92–0.98)). We discuss the rationale for the decisions made at every step in developing the models and have made our code available to the research community. We employed the best machine learning practices for clinical model development. Our goal is to create a toolkit that would assist investigators and organizations in building multi-modal models for prediction, classification, and/or optimization. Supplementary InformationThe online version contains supplementary material available at 10.1007/s10278-022-00674-z.     

Immunogenicity and Reactogenicity of Ad26.COV2.S in Korean Adults: A Prospective Cohort Study

BackgroundAs the coronavirus disease 2019 (COVID-19) pandemic continues, there are concerns regarding waning immunity and the emergence of viral variants. The immunogenicity of Ad26.COV2.S against wild-type (WT) and variants of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) needs to be evaluated.MethodThis prospective cohort study was conducted between June 2021 and January 2022 at two university hospitals in South Korea. Healthy adults who were scheduled to be vaccinated with Ad26.COV2.S were enrolled in this study. The main outcomes included anti-spike (S) IgG antibody and neutralizing antibody responses, S-specific T-cell responses (interferon-γ enzyme-linked immunospot assay), solicited adverse events (AEs), and serious AEs.ResultsFifty participants aged ≥ 19 years were included in the study. Geometric mean titers (GMTs) of anti-S IgG were 0.4 U/mL at baseline, 5.2 ± 3.0 U/mL at 3–4 weeks, 55.7 ± 2.4 U/mL at 5–8 weeks, and 81.3 ± 2.5 U/mL at 10–12 weeks after vaccination. GMTs of 50% neutralizing dilution (ND50) against WT SARS-CoV-2 were 164.6 ± 4.6 at 3-4 weeks, 313.9 ± 3.6 at 5–8 weeks, and 124.4 ± 2.6 at 10–12 weeks after vaccination. As for the S-specific T-cell responses, the median number of spot-forming units/10⁶ peripheral blood mononuclear cell was 25.0 (5.0–29.2) at baseline, 60.0 (23.3–178.3) at 5-8 weeks, and 35.0 (13.3–71.7) at 10–12 weeks after vaccination. Compared to WT SARS-CoV-2, ND50 against Delta and Omicron variants was attenuated by 3.6-fold and 8.2-fold, respectively. The most frequent AE was injection site pain (82%), followed by myalgia (80%), fatigue (70%), and fever (50%). Most AEs were grade 1–2, and resolved within two days.ConclusionSingle-dose Ad26.COV2.S was safe and immunogenic. NAb titer and S-specific T-cell immunity peak at 5–8 weeks and rather decrease at 10–12 weeks after vaccination. Cross-reactive neutralizing activity against the Omicron variant was negligible.     

Immunogenicity of COVID-19 Vaccination in Patients With End-Stage Renal Disease Undergoing Maintenance Hemodialysis: The Efficacy of a Mix-and-Match Strategy

BackgroundThe objective of this study was to evaluate the immunogenicity of coronavirus disease 2019 (COVID-19) vaccination in patients with end-stage renal disease (ESRD) on hemodialysis.MethodsESRD patients at the hemodialysis center of a tertiary-care university-affiliated hospital and healthy employees at the clinical laboratory center were prospectively recruited between March and June 2021. For severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody analysis, blood samples were collected serially on days 0, 14, 28, and 56 after the first vaccine dose, and on days 7 and 50 after the second dose. Antibodies against the SARS-CoV-2 spike protein were quantified, and SARS-CoV-2 neutralizing antibodies were measured in the serum and plasma.ResultsThirty-one ESRD patients and 55 healthy employees were regularly monitored. Twenty-five (80.6%) ESRD patients on hemodialysis received a mix-and-match strategy with ChAdOx1-BNT162b2 (AZ–Pf group) and six (19.4%) received two doses of ChAdOx1 (AZ–AZ group). ESRD patients on hemodialysis showed lower binding antibody titers and neutralizing antibody activities compared to healthy participants following the first vaccination with ChAdOx1. After the second dose, AZ-Pf group had higher immunogenicity than healthy people on days 7 and 50. The binding antibody titer and neutralizing antibody activities on days 7 and 50 were significantly higher in the AZ–Pf group than in the AZ–AZ group.ConclusionESRD patients on hemodialysis receiving the mix-and-match strategy (ChAdOx1–BNT162b2) have COVID-19 vaccine immunogenicity comparable to healthy individuals receiving two doses of ChAdOx1.Trial RegistrationClinicalTrials.gov Identifier: {"type":"clinical-trial","attrs":{"text":"NCT04871945","term_id":"NCT04871945"}}NCT04871945     

Longitudinal investigation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in older patients in the province of Palermo (Southern Italy) during the early wave of the pandemic

IntroductionClinical presentation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in old adults from Southern Italy is little known. This study aims to investigate the mortality risk related to risk factors, therapy and clinical course and to suggest prognostic indicators based on day-to-day follow-up of clinical and laboratory findings.Material and methodsIt was designed as a retrospective longitudinal cohort study of adult SARS-CoV-2 patients admitted at Partinico COVID Hospital in Palermo, Southern Italy. Patients were recruited between 4 March and 25 April and followed up until 31 May 2020, day-to-day until death or hospital discharge. Clinical data, laboratory tests and treatment data were extracted from medical records and epidemiologic information was obtained by clinical history and the medical interview.ResultsForty-seven patients (median age = 75 IQR: 59.50–86.00) were followed up during a 87 days observation period, accounting for a total of 1,035 person days. At the end of follow-up, 28 (60%) patients were discharged and 19 (40%) died, so that the estimated incidence density rate was 0.018 deaths per day (18 SARS-CoV-2-related deaths per 1,000 patient days). Diabetes (HR = 8.13, 95% CI: 1.91–34.67), chronic kidney failure (HR = 5.86, 95% CI: 1.36–25.21), dementia (HR = 7.84, 95% CI: 1.80–34.20), and neutrophil/lymphocyte ratio > 7 (HR = 10.37, 95% CI: 2.24–48.14) were found as significant prognostic factors.ConclusionsThe joint evaluation of dementia, diabetes, chronic kidney failure and neutrophil/lymphocyte ratio showed an optimal prognostic value already in the first week of follow-up. The day-to-day follow-up provides essential information for clinical monitoring and treatment of the disease in a hospital setting and improves the disease’s home management, especially for older patients with frailty.     

Higher Levels of C-Reactive Protein and Ferritin in Patients with Overweight and Obesity and SARS-CoV-2-Related Pneumonia

IntroductionOverweight and obesity are associated with a more severe COronaVirus Disease 19 (COVID-19). Adipose tissue-related chronic inflammation could be a promoter for the occurrence of the cytokine storm that predicts aggravation of COVID-19. The primary aim was to investigate if this increased risk for more severe COVID-19 was associated with a higher inflammatory response.MethodsWe enrolled patients <75 years old hospitalized in a medical COVID-19 ward with SARS-CoV-2-related pneumonia. Patients were classified according to BMI as normal weight, overweight, and obesity. Laboratory parameters were measured at admission and every second day during the hospital stay.ResultsNinety patients (64.4% males; median age 61 years) were enrolled. Invasive mechanical ventilation (IMV) was needed in 9% of the patients with normal weight, in 32.4% of the patients with overweight, and in 12.9% of the patients with obesity (p = 0.045). Maximal C-reactive protein (CRP) level during hospital stay was 92 (48–122) mg/L in patients with normal weight, 140 (82–265) mg/L in patients with overweight, and 117 (67–160) mg/L in patients with obesity (p = 0.037). Maximal ferritin values were 564 (403–1,379) μg/L in patients with a normal weight, 1,253 (754–2,532) μg/L in patients with overweight, and 828 (279–1,582) μg/L in patients with obesity (p = 0.015).ConclusionPatients with overweight and obesity required more IMV and had higher peaks of CRP and ferritin than patients with normal weight during COVID-19.     

Prevalence of SARS-CoV-2 Antibody in 2,935 Healthcare Workers at 6 Major Hospitals,Daegu, Korea

BackgroundIn Korea, the first community outbreak of coronavirus disease 2019 (COVID-19) occurred in Daegu on February 18, 2020. This study was performed to investigate the prevalence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) antibodies in healthcare workers (HCWs) at 6 major hospitals in Daegu.MethodsBlood specimens of 2,935 HCWs at 6 major hospitals in Daegu from January 2021 to February 2021 were collected. Every specimen was tested for antibody against SARS-CoV-2 using both Elecsys Anti-SARS-CoV-2 electrochemiluminescence immunoassay (Roche Diagnostics, Rotkreuz, Switzerland) and R-FIND COVID-19 IgG/M/A enzyme-linked immunosorbent assay kit (SG medical Inc., Seoul, Korea) as screening tests. If 1 or more of these screening test results was positive, 2 additional antibody tests were performed using Abbott Anti-SARS-CoV-2 IgG assay (Abbott, Abbott Park, IL, USA) and cPass SARS-CoV-2 Neutralization Antibody Detection Kit (GenScript USA Inc., Piscataway, NJ, USA). If 2 or more of the total 4 test results were positive, it was determined as positive for the antibody against SARS-CoV-2.ResultsAccording to the criteria of SARS-CoV-2 antibody positivity determination, 12 subjects were determined as positive. The overall positive rate of the SARS-CoV-2 antibody was 0.41% (12/2,935). Of the 12 subjects determined as positive, 7 were diagnosed with COVID-19, and the remaining 5 were nondiagnosed cases of COVID-19.ConclusionIn early 2021, the overall seroprevalence of SARS-CoV-2 antibody among HCW located in Daegu was 0.41%, and 0.17% excluding COVID-19 confirmed subjects. These results were not particularly high compared with the general public and were much lower than HCWs in other countries.     

Clinical Features of Adult COVID-19 Patients without Risk Factors before and after the Nationwide SARS-CoV-2 B.1.617.2 (Delta)-variant Outbreak in Korea: Experience from Gyeongsangnam-do

BackgroundData on severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) delta variant virulence are insufficient. We retrospectively compared the clinical features of adult coronavirus disease 2019 (COVID-19) patients without risk factors for severe COVID-19 who entered residential treatment centers (RTCs) before and after the delta variant outbreak.MethodsWe collected medical information from two RTCs in South Korea. On the basis of nationwide delta variant surveillance, we divided the patients into two groups: 1) the delta-minor group (diagnosed from December 2020–June 2021, detection rate < 10%) and 2) the delta-dominant group (diagnosed during August 2021, detection rate > 90%). After propensity-score matching, the incidences of pneumonia, hospital transfer and need for supplemental oxygen were compared between the groups. In addition, risk factors for hospital transfer were analysed.ResultsA total of 1,915 patients were included. The incidence of pneumonia (14.6% vs. 9.2%, P = 0.009), all-cause hospital transfer (10.4% vs. 6.3%, P = 0.020) and COVID-19-related hospital transfer (7.5% vs. 4.8%, P = 0.081) were higher in the delta-dominant group than those in the delta-minor group. In the multivariate analysis, the delta-dominant group was an independent risk factor for all-cause (adjusted odds ratio [aOR], 1.91; 95% confidence interval [CI], 1.16–3.13; P = 0.011) and COVID-19-related hospital transfer (aOR, 1.86; 95% CI, 1.04–3.32; P = 0.036).ConclusionHospitalization rates were increased in the adult COVID-19 patients during the delta variant nationwide outbreak. Our results showed that the delta variant may be more virulent than previous lineages.     

Coronavirus Disease 2019 Cases at Universities and Colleges in Seoul Metropolitan Area

BackgroundTo facilitate evidence-based policy-making on safe reopening of higher education facilities, there is an urgent need to assess baseline profile of coronavirus disease 2019 (COVID-19) incidents within the university/college settings. We aimed to describe the epidemiology of COVID-19 in universities/colleges in Seoul Metropolitan Area during COVID-19 pandemic period.MethodsAmong the 38 universities in Seoul, 23 have agreed to participate in the study. Confirmed COVID-19 cases were identified from individual-level case reports submitted to the universities and to the health authorities from February 1, 2020, to June 30, 2021. Through the linkage with the Central Disease Control Headquarters'' database, number of secondary infected cases (both within and outside of the campus) were counted.ResultsBetween February 2020 and June 2021, a total of 827 COVID-19 cases were confirmed and reported in the universities across Seoul Metropolitan City. Generally, the community-associated cases had peaks preceding the university/college-associated. Of those with the documented clinical parameters, 38.6% of the cases were asymptomatic. Among them, 93% were potentially exposed off-campus, and 87.7% of the cases had not produced the secondary infection cases.ConclusionIn the setting of rigorous infection prevention measures in combination with on- and off- hybrid classes, COVID-19 incidences and outbreaks were limited in university and college campus area across Seoul Metropolitan Area. The evidence around the infection preventive measures in higher education facilities in Seoul Metropolitan Area, suggest insignificant impact on community transmission.     

One Year Follow-Up of COVID-19 Related Symptoms and Patient Quality of Life: A Prospective Cohort Study

PurposeGlobally, concerns have grown regarding the long-term effects of novel coronavirus disease (COVID-19) infection. Therefore, we evaluated the long-term course of persistent symptoms and patient quality of life.Materials and MethodsThis prospective cohort study was conducted at a single tertiary university hospital from August 31, 2020 to March 29, 2021 with adult patients followed at 6 and 12 months after acute COVID-19 symptom onset or diagnosis. Clinical characteristics, self-reported symptoms, EuroQol 5 dimension 5 level (EQ5D-5L) index scores, Korean version of the Patient Health Questionnaire-9 (PHQ-9), Korean version of the Posttraumatic Stress Disorder Checklist-5 (PCL-5-K), and Generalized Anxiety Disorder-7 (GAD-7) were investigated. Symptom persistent or non-persistent groups were defined according to persistency of COVID-19 related symptoms or signs after acute COVID-19 infection, respectively.ResultsOf all 235 patients, 170 (64.6%) patients were eligible for analysis. The median age was 51 (interquartile range, 37–61) years old, and 102 patients were female (60.0%). After 12 months from acute COVID-19 infection, in total, 83 (48.8%) patients still suffered from COVID-19-related symptoms. The most common symptoms included amnesia (24.1%), insomnia (14.7%), fatigue (13.5%), and anxiety (12.9%). Among the five EQ5D-5L categories, the average value of anxiety or depression was the most predominant. PHQ-9 and PCL-5-K scores were statistically higher in the COVID-19–related symptom persistent group than the non-persistent group (p=0.001). However, GAD-7 scores showed no statistical differences between the two groups (p=0.051).ConclusionNeuropsychiatric symptoms were the major COVID-19–related symptoms after 12 months from acute COVID-19 infection, reducing quality of life.     

Analysis of a COVID-19 Prescreening Process in an Outpatient Clinic at a University Hospital during the COVID-19 Pandemic

BackgroundTo minimize nosocomial infection against coronavirus disease 2019 (COVID-19), most hospitals conduct a prescreening process to evaluate the patient or guardian of any symptoms suggestive of COVID-19 or exposure to a COVID-19 patient at entrances of hospital buildings. In our hospital, we have implemented a two-level prescreening process in the outpatient clinic: an initial prescreening process at the entrance of the outpatient clinic (PPEO) and a second prescreening process is repeated in each department. If any symptoms or epidemiological history are identified at the second level, an emergency code is announced through the hospital''s address system. The patient is then guided outside through a designated aisle. In this study, we analyze the cases missed in the PPEO that caused the emergency code to be applied.MethodsAll cases reported from March 2020 to April 2021 were analyzed retrospectively. We calculated the incidence of cases missed by the PPEO per 1,000 outpatients and compared the incidence between first-time hospital visitors and those visiting for the second time or more; morning and afternoon office hours; and days of the week.ResultsDuring the study period, the emergency code was applied to 449 cases missed by the PPEO. Among those cases, 20.7% were reported in otorhinolaryngology, followed by 11.6% in gastroenterology, 5.8% in urology, and 5.8% in dermatology. Fever was the most common symptom (59.9%), followed by cough (19.8%). The incidence of cases per 1,000 outpatients was significantly higher among first-time visitors than among those visiting for the second time or more (1.77 [confidence interval (CI), 1.44–2.10] vs. 0.59 [CI, 0.52–0.65], respectively) (P < 0.001).ConclusionFever was the most common symptom missed by the PPEO, and otorhinolaryngology and gastroenterology most frequently reported missed cases. Cases missed by the PPEO were more likely to occur among first-time visitors than returning visitors. The results obtained from this study can provide insights or recommendations to other healthcare facilities in operating prescreening processes during the COVID-19 pandemic.