Immunogenicity Differences of the ChAdOx1 nCoV-19 Vaccine According to Pre-Existing Adenovirus Immunity.

This study investigated the immunogenicity of, and reactogenicity to, the ChAdOx1 nCoV-19 vaccine according to pre-existing adenovirus immunity. Individuals scheduled for COVID-19 vaccination were prospectively enrolled in a tertiary hospital with 2400 beds from March 2020 onwards. Pre-existing adenovirus immunity data was obtained before ChAdOx1 nCoV-19 vaccination. A total of 68 adult patients administered two doses of the ChAdOx1 nCoV-19 vaccine were enrolled. Pre-existing adenovirus immunity was identified in 49 patients (72.1%), but not in the remaining 19 patients (27.9%). The geometric mean titer of S-specific IgG antibodies was statistically higher in individuals without pre-existing adenovirus immunity at several time points: before the second ChAdOx1 nCoV-19 dose (56.4 (36.6-125.0) vs. 51.0 (17.9-122.3), p = 0.024), 2-3 weeks after the second ChAdOx1 nCoV-19 dose (629.5 (451.5-926.5) vs. 555.0 (287.3-926.0), p = 0.049), and 3 months after the second ChAdOx1 nCoV-19 dose (274.5 (160.5-655.3) vs. 176.0 (94.3-255.3), p = 0.033). In the absence of pre-existing adenovirus immunity, systemic events were observed with higher frequency, especially chills (73.7% vs. 31.9%, p = 0.002). In conclusion, individuals without pre-existing adenovirus immunity showed a higher immune response to ChAdOx1 nCoV-19 vaccination and a higher frequency of reactogenicity to ChAdOx1 nCoV-19 vaccination was observed.

Risk factors of pneumothorax and pneumomediastinum in COVID-19: a matched case-control study.

BACKGROUND: During the novel coronavirus disease-2019 pandemic, a considerable number of pneumothorax (PNX)/pneumomediastinum (PNM) associated with COVID-19 have been reported, and the incidence is higher in critically ill patients. Despite using a protective ventilation strategy, PNX/PNM still occurs in patients on invasive mechanical ventilation (IMV). This matched case-control study aims to identify the risk factors and clinical characteristics of PNX/PNM in COVID-19. METHODS: This retrospective study enrolled adult patients with COVID-19, admitted to a critical care unit from March 1, 2020, to January 31, 2022. COVID-19 patients with PNX/PNM were compared, in a 1-2 ratio, to COVID-19 patients without PNX/PNM, matched for age, gender, and worst National Institute of Allergy and Infectious Diseases ordinal scale. Conditional logistic regression analysis was performed to assess the risk factors for PNX/PNM in COVID-19. RESULTS: 427 patients with COVID-19 were admitted during the period, and 24 patients were diagnosed with PNX/PNM. Body mass index (BMI) was significantly lower in the case group (22.8 kg/m2 and 24.7 kg/m2; P = 0.048). BMI was statistically significant risk factor for PNX/PNM in univariate conditional logistic regression analysis [odds ratio (OR), 0.85; confidence interval (CI), 0.72-0.996; P = 0.044]. For patients on IMV support, univariate conditional logistic regression analysis showed the statistical significance of the duration from symptom onset to intubation (OR, 1.14; CI, 1.006-1.293; P = 0.041). CONCLUSIONS: Higher BMI tended to show a protective effect against PNX/PNM due to COVID-19 and delayed application of IMV might be a contributive factor for this complication.

Immunogenicity and Safety of Vaccines against Coronavirus Disease in Actively Treated Patients with Solid Tumors: A Prospective Cohort Study.

PURPOSE: We aimed to assess the humoral response to and reactogenicity of coronavirus disease 2019 (COVID-19) vaccination according to the vaccine type and to analyze factors associated with immunogenicity in actively treated solid cancer patients (CPs). Materials and Methods: Prospective cohorts of CPs, undergoing anticancer treatment, and healthcare workers (HCWs) were established. The participants had no history of previous COVID-19 and received either mRNA-based or adenovirus vector-based (AdV) vaccines as the primary series. Blood samples were collected before the first vaccination and after 2 weeks for each dose vaccination. Spike-specific binding antibodies (bAbs) in all participants and neutralizing antibodies (nAbs) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) wild-type, Delta, and Omicron variants in CPs were analyzed and presented as the geometric mean titer. RESULTS: Age-matched 20 HCWs and 118 CPs were included in the analysis. The bAb seroconversion rate and antibody concentrations after the first vaccination were significantly lower in CPs than in HCWs. After the third vaccination, antibody levels in CPs with a primary series of AdV were comparable to those in HCWs, but nAb titers against the Omicron variant did not quantitatively increase in CPs with AdV vaccine as the primary series. The incidence and severity of adverse reactions post-vaccination were similar between CPs and HCWs. CONCLUSION: CPs displayed delayed humoral immune response after SARS-CoV-2 vaccination. The booster dose elicited comparable bAb concentrations between CPs and HCWs, regardless of the primary vaccine type. Neutralization against the Omicron variant was not robustly elicited following the booster dose in some CPs, implying the need for additional interventions to protect them from COVID-19.

A heterologous AZD1222 priming and BNT162b2 boosting regimen more efficiently elicits neutralizing antibodies, but not memory T cells, than the homologous BNT162b2 regimen.

BACKGROUND: Comparative analyses of SARS-CoV-2-specific immune responses elicited by diverse prime-boost regimens are required to establish efficient regimens for the control of COVID-19. METHOD: In this prospective observational cohort study, spike-specific immunoglobulin G (IgG) and neutralizing antibodies (nAbs) alongside spike-specific T-cell responses in age-matched groups of homologous BNT162b2/BNT162b2 or AZD1222/AZD1222 vaccination, heterologous AZD1222/BNT162b2 vaccination, and prior wild-type SARS-CoV-2 infection/vaccination were evaluated. RESULTS: Peak immune responses were achieved after the second vaccine dose in the naïve vaccinated groups and after the first dose in the prior infection/vaccination group. Peak titers of anti-spike IgG and nAb were significantly higher in the AZD1222/BNT162b2 vaccination and prior infection/vaccination groups than in the BNT162b2/BNT162b2 or AZD1222/AZD1222 groups. However, the frequency of interferon-γ-producing CD4+ T cells was highest in the BNT162b2/BNT162b2 vaccination group. Similar results were observed in the analysis of polyfunctional T cells. When nAb and CD4+T-cell responses against the Delta variant were analyzed, the prior infection/vaccination group exhibited higher responses than the groups of other homologous or heterologous vaccination regimens. CONCLUSION: nAbs are efficiently elicited by heterologous AZD1222/BNT162b2 vaccination, as well as prior infection/vaccination, whereas spike-specific CD4+T-cell responses are efficiently elicited by homologous BNT162b2 vaccination. Variant-recognizing immunity is more efficiently generated by prior infection/vaccination than the other homologous or heterologous vaccination regimens.

Estimation of SARS-CoV-2 Neutralizing Activity and Protective Immunity in Different Vaccine Types Using Three Surrogate Virus Neutralization Test Assays and Two Semiquantitative Binding Assays Targeting the Receptor-Binding Domain.

Estimating neutralizing activity in vaccinees is crucial for predicting the protective effect against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). As the plaque reduction neutralization test (PRNT) requires a biosafety level 3 facility, it would be advantageous if surrogate virus neutralization test (sVNT) assays and binding assays could predict neutralizing activity. Here, five different assays were evaluated with respect to the PRNT in vaccinees: three sVNT assays from GenScript, Boditech Med, and SD Biosensor and two semiquantitative binding assays from Roche and Abbott. The vaccinees were subjected to three vaccination protocols: homologous ChAdOx1, homologous BNT162b2, and heterologous administration. The ability to predict a 50% neutralizing dose (ND50) of ≥20 largely varied among the assays, with the binding assays showing substantial agreement (kappa, ~0.90) and the sVNT assays showing relatively poor performance, especially in the ChAdOx1 group (kappa, 0.33 to 0.97). The ability to predict an ND50 value of ≥118.25, indicating a protective effect, was comparable among different assays. Applying optimal cutoffs based on Youden's index, the kappa agreements were greater than 0.60 for all assays in the total group. Overall, relatively poor performance was demonstrated in the ChAdOx1 group, owing to low antibody titers. Although there were intra-assay differences related to the vaccination protocols, as well as interassay differences, all assays demonstrated fair performance in predicting the protective effect using the new cutoffs. This study demonstrates the need for a different cutoff for each assay to appropriately determine a higher neutralizing titer and suggests the clinical feasibility of using various assays for estimation of the protective effect. IMPORTANCE The coronavirus disease 2019 (COVID-19) pandemic continues to last, despite high COVID-19 vaccination rates. As many people experience breakthrough infection after prior infection and/or vaccination, estimating the neutralization activity and predicting the protective effect are major issues of concern. However, since standard neutralization tests are not available in most clinical laboratories, it would be beneficial if commercial assays could predict these aspects. In this study, we evaluated the performance of three sVNT assays and two semiquantitative binding assays targeting the receptor-binding domain with respect to the PRNT. Our results suggest that these assays could be used for predicting the protective effect by adjusting the cutoffs.

Kinetics of vaccine-induced neutralizing antibody titers and estimated protective immunity against wild-type SARS-CoV-2 and the Delta variant: A prospective nationwide cohort study comparing three COVID-19 vaccination protocols in South Korea.

Introduction: Despite vaccine development, the COVID-19 pandemic is ongoing due to immunity-escaping variants of concern (VOCs). Estimations of vaccine-induced protective immunity against VOCs are essential for setting proper COVID-19 vaccination policy. Methods: We performed plaque-reduction neutralizing tests (PRNTs) using sera from healthcare workers (HCWs) collected from baseline to six months after COVID-19 vaccination and from convalescent COVID-19 patients. The 20.2% of the mean PRNT titer of convalescent sera was used as 50% protective value, and the percentage of HCWs with protective immunity for each week (percent-week) was compared among vaccination groups. A correlation equation was deduced between a PRNT 50% neutralizing dose (ND50) against wild type (WT) SARS-CoV-2 and that of the Delta variant. Results: We conducted PRNTs on 1,287 serum samples from 297 HCWs (99 HCWs who received homologous ChAdOx1 vaccination (ChAd), 99 from HCWs who received homologous BNT162b2 (BNT), and 99 from HCWs who received heterologous ChAd followed by BNT (ChAd-BNT)). Using 365 serum samples from 116 convalescent COVID-19 patients, PRNT ND50 of 118.25 was derived as 50% protective value. The 6-month cumulative percentage of HCWs with protective immunity against WT SARS-CoV-2 was highest in the BNT group (2297.0 percent-week), followed by the ChAd-BNT (1576.8) and ChAd (1403.0) groups. In the inter-group comparison, protective percentage of the BNT group (median 96.0%, IQR 91.2-99.2%) was comparable to the ChAd-BNT group (median 85.4%, IQR 15.7-100%; P =0.117) and significantly higher than the ChAd group (median 60.1%, IQR 20.0-87.1%; P <0.001). When Delta PRNT was estimated using the correlation equation, protective immunity at the 6-month waning point was markedly decreased (28.3% for ChAd group, 52.5% for BNT, and 66.7% for ChAd-BNT). Conclusion: Decreased vaccine-induced protective immunity at the 6-month waning point and lesser response against the Delta variant may explain the Delta-dominated outbreak of late 2021. Follow-up studies for newly-emerging VOCs would also be needed.

Neutralizing Activity Against SARS-CoV-2 Delta and Omicron Variants Following a Third BNT162b2 Booster Dose According to Three Homologous or Heterologous COVID-19 Vaccination Schedules.

With the emergence and rapid spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Delta and Omicron variants, escaping vaccine-induced immunity is a concern. Three vaccination schedules, homologous or heterologous, have been initially applied due to an insufficient supply of vaccines in Korea. We investigated neutralizing activities against Omicron and Delta variants in each schedule. Three schedules using three doses of the BNT162b2 (BNT) or the ChAdOx1 (ChAd) vaccines include ChAd-ChAd-BNT, ChAd-BNT-BNT, and BNT-BNT-BNT. Neutralizing activities were evaluated using plaque-reduction neutralization test (PRNT) against wild type (WT) SARS-CoV-2, Delta variant, and Omicron variant. A total of 170 sera from 75 participants were tested, and the baseline characteristics of participants were not significantly different between groups. After the 2nd vaccine dose, geometric mean titers of PRNT ND50 against WT, Delta, and Omicron were highest after ChAd-BNT vaccination (2,463, 1,097, and 107) followed by BNT-BNT (2,364, 674, and 38) and ChAd-ChAd (449, 163, and 25). After the 3rd dose of BNT, the increase of PRNT ND50 against WT, Delta, and Omicron was most robust in ChAd-ChAd-BNT (4,632, 988, and 260), while the BNT-BNT-BNT group showed the most augmented neutralizing activity against Delta and Omicron variants (2,315 and 628). ChAd-BNT-BNT showed a slight increase of PRNT ND50 against WT, Delta, and Omicron (2,757, 1,279, and 230) compared to the 2nd dose. The results suggest that a 3rd BNT booster dose induced strengthened neutralizing activity against Delta and Omicron variants. The waning of cross-reactive neutralizing antibodies after the 3rd dose and the need for additional boosting should be further investigated.

Heterologous ChAdOx1 and Bnt162b2 vaccination induces strong neutralizing antibody responses against SARS-CoV-2 including delta variant with tolerable reactogenicity.

OBJECTIVES: We assessed humoral responses and reactogenicity following the heterologous vaccination compared to the homologous vaccination groups. METHODS: We enrolled healthcare workers (HCWs) who were either vaccinated with ChAdOx1 followed by BNT162b2 (heterologous group) or 2 doses of ChAdOx1 (ChAdOx1 group) or BNT162b2 (BNT162b2 group). Immunogenicity was assessed by measuring antibody titers against receptor-binding domain (RBD) of SARS-CoV-2 spike protein in all participants and neutralizing antibody titer in 100 participants per group. Reactogenicity was evaluated by a questionnaire-based survey. RESULTS: We enrolled 499 HCWs (ChAdOx1, n = 199; BNT162b2, n = 200; heterologous ChAdOx1/BNT162b2, n = 100). The geometric mean titer of anti-receptor-binding domain antibody at 14 days after the booster dose was significantly higher in the heterologous group (11 780.55 binding antibody unit (BAU)/mL [95% CI, 10 891.52-12 742.14]) than in the ChAdOx1 (1561.51 [95% CI, 1415.03-1723.15]) or BNT162b2 (2895.90 [95% CI, 2664.01-3147.98]) groups (both p < 0.001). The neutralizing antibody titer of the heterologous group (geometric mean ND50, 2367.74 [95% CI, 1970.03-2845.74]) was comparable to that of the BNT162b2 group (2118.63 [95% CI, 1755.88-2556.32]; p > 0.05) but higher than that of the ChAdOx1 group (391.77 [95% CI, 326.16-470.59]; p < 0.001). Compared with those against wild-type SARS-CoV-2, the geometric mean neutralizing antibody titers against the Delta variant at 14 days after the boosting were reduced by 3.0-fold in the heterologous group (geometric mean ND50, 872.01 [95% CI, 685.33-1109.54]), 4.0-fold in the BNT162b2 group (337.93 [95% CI, 262.78-434.57]), and 3.2-fold in the ChAdOx1 group (206.61 [95% CI, 144.05-296.34]). The local or systemic reactogenicity after the booster dose in the heterologous group was higher than that of the ChAdOx1 group but comparable to that of the BNT162b2 group. DISCUSSION: Heterologous ChAdOx1 followed by BNT162b2 vaccination with a 12-week interval induced a robust humoral immune response against SARS-CoV-2, including the Delta variant, that was comparable to the homologous BNT162b2 vaccination and stronger than the homologous ChAdOx1 vaccination, with a tolerable reactogenicity profile.

Safety and immunogenicity of two recombinant DNA COVID-19 vaccines containing the coding regions of the spike or spike and nucleocapsid proteins: an interim analysis of two open-label, non-randomised, phase 1 trials in healthy adults.

BACKGROUND: We assessed the safety and immunogenicity of two recombinant DNA vaccines for COVID-19: GX-19 containing plasmid DNA encoding the SARS-CoV-2 spike protein, and GX-19N containing plasmid DNA encoding the SARS-CoV-2 receptor-binding domain (RBD) foldon, nucleocapsid protein, and plasmid DNA encoding the spike protein. METHODS: Two open-label non-randomised phase 1 trials, one of GX-19 and the other of GX-19N were done at two hospitals in South Korea. We enrolled healthy adults aged 19-49 years for the GX-19 trial and healthy adults aged 19-54 years for the GX-19N trial. Participants who tested positive by serological testing for SARS-CoV-2 were excluded. At 4-week intervals, the GX-19 trial participants received two vaccine doses (either 1·5 mg or 3·0 mg), and the GX-19N trial participants received two 3·0 mg doses. The vaccines were delivered intramuscularly using an electroporator. The participants were followed up for 52 weeks after first vaccination. Data collected up to day 57 after first vaccination were analysed in this interim analysis. The primary outcome was safety within 28 days after each vaccination measured in the intention-to-treat population. The secondary outcome was vaccine immunogenicity using blood samples collected on day 43 or 57 after first vaccination measured in the intention-to-treat population. The GX-19 (NCT044445389) and GX-19N (NCT04715997) trials are registered with ClinicalTrials.gov. FINDINGS: Between June 17 and July 30, 2020, we screened 97 individuals, of whom 40 (41%) participants were enrolled in the GX-19 trial (20 [50%] in the 1·5 mg group and 20 [50%] in the 3·0 mg group). Between Dec 28 and 31, 2020, we screened 23 participants, of whom 21 (91%) participants were enrolled on the GX-19N trial. 32 (52%) of 61 participants reported 80 treatment-emergent adverse events after vaccination. All solicited adverse events were mild except one (2%) case of moderate fatigue in the 1·5 mg GX-19 group; no serious vaccine-related adverse events were detected. Binding antibody responses increased after second dose of vaccination in all groups (p=0·0002 in the 1·5 mg GX-19 group; p<0·0001 in the 3·0 mg GX-19; and p=0·0004 for the spike protein and p=0·0001 for the RBD in the 3·0 mg GX-19N group). INTERPRETATION: GX-19 and GX-19N are safe and well tolerated. GX-19N induces humoral and broad SARS-CoV-2-specific T-cell responses. GX-19N shows lower neutralising antibody responses and needs improvement to enhance immunogenicity. FUNDING: The Korea Drug Development Fund, funded by the Ministry of Science and ICT, Ministry of Trade, Industry, and Energy, and Ministry of Health and Welfare.

Surveillance of Close Contacts and Implications of Pediatric Patients with COVID-19-Experiences from a Single Residential Treatment Center.

Residential treatment centers (RTCs) are successful in isolating and closely monitoring adults confirmed with coronavirus disease 2019 (COVID-19), but there are concerns for children who need care. This study was conducted as a retrospective analysis of the surveillance of guardians who entered an RTC with infected pediatric patients to identify the secondary attack rate of COVID-19 to close contacts in a single RTC and to provide directions for developing guidelines for caregivers who co-isolate with infected children. When caregivers were admitted to this RTC, aside from negative confirmation before discharge, tests were additionally performed one or two times. There were 57 index children and adolescent patients who entered the RTC with their parents as caregivers. The secondary attack rate by pediatric patients to close contacts outside their households was 25% (95% confidence interval, 10.0 to 40.0) (8 out of 32 contacts). The transmissibility of SARS-CoV-2 in children was close to zero at 6 days after the confirmation tests. It is reasonable to test the close contacts of pediatric patients after 7 days of isolation to identify infections among caregivers.

Soluble IL-2R Levels Predict in-Hospital Mortality in COVID-19 Patients with Respiratory Failure.

Acute respiratory distress syndrome is the primary cause of death in patients with coronavirus disease 2019 (COVID-19) pneumonia. Our study aims to determine the association between serum markers and mortality in COVID-19 patients with respiratory failure. This retrospective study was conducted in a tertiary care hospital in South Korea. Forty-nine patients with COVID-19, who required high flow nasal cannulation or mechanical ventilation from February 2020 to April 2021, were included. Demographic and laboratory data were analyzed at baseline and on Day 7 of admission. We found that serum creatinine, troponin, procalcitonin, and soluble interleukin-2 receptor (sIL-2R) at baseline were more elevated in the non-survivor group, but were not associated with mechanical ventilator use on Day 7. Older age, PaO2/FiO2 ratio, lymphocyte and platelet counts, lactate dehydrogenase, IL-6, C-reactive protein, and sIL-2R on Day 7 were significantly associated with mortality. Delta sIL-2R (Day 7-Day 0) per standard deviation was significantly higher in the non-survivor group (adjusted hazard ratio 3.225, 95% confidence interval (CI) 1.151-9.037, p = 0.026). Therefore, sIL-2R could predict mortality in COVID-19 patients with respiratory failure. Its sustained elevation suggests a hyper-inflammatory state, and mirrors the severity of COVID-19 in patients with respiratory failure, thereby warranting further attention.

Correction: A mathematical model of COVID-19 transmission in a tertiary hospital and assessment of the effects of different intervention strategies.

[This corrects the article DOI: 10.1371/journal.pone.0241169.].

Effects of early corticosteroid use in patients with severe coronavirus disease 2019.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is associated with acute respiratory distress syndrome, and corticosteroids have been considered as possible therapeutic agents for this disease. However, there is limited literature on the appropriate timing of corticosteroid administration to obtain the best possible patient outcomes. METHODS: This was a retrospective cohort study including patients with severe COVID-19 who received corticosteroid treatment from March 2 to June 30, 2020 in seven tertiary hospitals in South Korea. We analyzed the patient demographics, characteristics, and clinical outcomes according to the timing of steroid use. Twenty-two patients with severe COVID-19 were enrolled, and they were all treated with corticosteroids. RESULTS: Of the 22 patients who received corticosteroids, 12 patients (55%) were treated within 10 days from diagnosis. There was no significant difference in the baseline characteristics. The initial PaO2/FiO2 ratio was 168.75. The overall case fatality rate was 25%. The mean time from diagnosis to steroid use was 4.08 days and the treatment duration was 14 days in the early use group, while those in the late use group were 12.80 days and 18.50 days, respectively. The PaO2/FiO2 ratio, C-reactive protein level, and cycle threshold value improved over time in both groups. In the early use group, the time from onset of symptoms to discharge (32.4 days vs. 60.0 days, P = 0.030), time from diagnosis to discharge (27.8 days vs. 57.4 days, P = 0.024), and hospital stay (26.0 days vs. 53.9 days, P = 0.033) were shortened. CONCLUSIONS: Among patients with severe COVID-19, early use of corticosteroids showed favorable clinical outcomes which were related to a reduction in the length of hospital stay.

Use of Convalescent Plasma Therapy in Two COVID-19 Patients with Acute Respiratory Distress Syndrome in Korea

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus-2 not yet has established its treatment, but convalescent plasma has been expected to increase survival rates as in the case with other emerging viral infections.We describe two cases of COVID-19 treated with convalescent plasma infusion. Both patients presented severe pneumonia with acute respiratory distress syndrome and showed a favorable outcome after the use of convalescent plasma in addition to systemic corticosteroid. To our knowledge, this is the first report of the use of convalescent plasma therapy for COVID-19 in Korea.

PD-1-Expressing SARS-CoV-2-Specific CD8+ T Cells Are Not Exhausted, but Functional in Patients with COVID-19.

Memory T cell responses have been demonstrated in COVID-19 convalescents, but ex vivo phenotypes of SARS-CoV-2-specific T cells have been unclear. We detected SARS-CoV-2-specific CD8+ T cells by MHC class I multimer staining and examined their phenotypes and functions in acute and convalescent COVID-19. Multimer+ cells exhibited early differentiated effector-memory phenotypes in the early convalescent phase. The frequency of stem-like memory cells was increased among multimer+ cells in the late convalescent phase. Cytokine secretion assays combined with MHC class I multimer staining revealed that the proportion of interferon-γ (IFN-γ)-producing cells was significantly lower among SARS-CoV-2-specific CD8+ T cells than those specific to influenza A virus. Importantly, the proportion of IFN-γ-producing cells was higher in PD-1+ cells than PD-1- cells among multimer+ cells, indicating that PD-1-expressing, SARS-CoV-2-specific CD8+ T cells are not exhausted, but functional. Our current findings provide information for understanding of SARS-CoV-2-specific CD8+ T cells elicited by infection or vaccination.

Genome Sequences of Two GH Clade SARS-CoV-2 Strains Isolated from Patients with COVID-19 in South Korea.

We report the genome sequences of two GH clade severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) strains isolated from nasopharyngeal swabs from patients with coronavirus disease 2019 (COVID-19) in South Korea. These strains had two mutations in the untranslated regions and seven nonsynonymous substitutions in open reading frames, compared with Wuhan/Hu-1/2019, showing 99.96% sequence identity.

Clinical characteristics and online mental health care of asymptomatic or mildly symptomatic patients with coronavirus disease 2019.

Comparing to data in patients with severe coronavirus diseases 2019 (COVID-19), there are few studies on the prevalence anxiety and/or depression in patients with asymptomatic or mildly symptomatic COVID-19. We investigated the clinical characteristics and the prevalence of anxiety and/or depression among asymptomatic or mildly symptomatic patients with COVID-19 and monitored their mental health using an online assessment. An online survey for monitoring and assessing the mental health of patients with COVID-19 using a mobile phone was conducted. We used the Hospital Anxiety and Depression Scale to measure anxiety and/or depression levels. Of the 234 patients, 66 patients were asymptomatic (28.2%), while the remaining 168 patients were mildly symptomatic. The prevalence of anosmia (p = 0.001) and ageusia (p = 0.008) significantly decreased with the increasing age. In addition, 19.8% and 14.0% patients had anxiety and/or depression in the first survey, and one week after the first survey, respectively. Compared to patients without anxiety and/or depression, those with anxiety and/or depression had a longer quarantine duration. We found that anomia and ageusia were relatively common in the young age group. Furthermore, one-fifth asymptomatic or mildly symptomatic patients with COVID-19 had anxiety and/or depression.

A mathematical model of COVID-19 transmission in a tertiary hospital and assessment of the effects of different intervention strategies.

Novel coronavirus (named SARS-CoV-2) can spread widely in confined settings including hospitals, cruise ships, prisons, and places of worship. In particular, a healthcare-associated outbreak could become the epicenter of coronavirus disease (COVID-19). This study aimed to evaluate the effects of different intervention strategies on the hospital outbreak within a tertiary hospital. A mathematical model was developed for the COVID-19 transmission within a 2500-bed tertiary hospital of South Korea. The SEIR (susceptible-exposed-infectious-recovered) model with a compartment of doctor, nurse, patient, and caregiver was constructed. The effects of different intervention strategies such as front door screening, quarantine unit for newly admitted patients, early testing of suspected infected people, and personal protective equipment for both medical staff and visitors were evaluated. The model suggested that the early testing (within eight hours) of infected cases and monitoring the quarantine ward for newly hospitalized patients are effective measures for decreasing the incidence of COVID-19 within a hospital (81.3% and 70% decrease of number of incident cases, respectively, during 60 days). Front door screening for detecting suspected cases had only 42% effectiveness. Screening for prohibiting the admission of COVID-19 patients was more effective than the measures for patients before emergency room or outpatient clinic. This model suggests that under the assumed conditions, some effective measures have a great influence on the incidence of COVID-19 within a hospital. The implementation of the preventive measures could reduce the size of a hospital outbreak.