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2.
Journal of Hospital Infection ; 2022.
Article in English | ScienceDirect | ID: covidwho-2131503

ABSTRACT

Summary Objectives There have been limited data on the risk of onward transmission from individuals with Omicron variant infections who return to work after a 5-day isolation. We evaluated the risk of transmission from healthcare workers (HCWs) with Omicron variant who returned to work after a 5-day isolation and the viable virus shedding kinetics. Methods This investigation was performed in a tertiary care hospital, Seoul, South Korea. In a secondary transmission study, we retrospectively reviewed the data of HCWs confirmed as COVID-19 from March 14 to April 3, 2022 in units with 5 or more COVID-19-infected HCWs per week. In the viral shedding kinetics study, HCWs with Omicron variant infection who agreed with daily saliva sampling were enrolled between February and March, 2022. Results Of the 248 HCWs who were diagnosed with COVID-19 within 5 days of the return of an infected HCW, 18 (7%) had contact with the returned HCW within 1 to 5 days after their return. Of these, 9 (4%) had an epidemiologic link other than with the returning HCW, and 9 (4%) had contact with the returning HCW, without any other epidemiologic link. In the study of the kinetics of virus shedding (n=32), the median time from symptom onset to negative conversion of viable virus was 4 days (95% CI, 3 to 5 days). Conclusions Our data suggest that the residual risk of virus transmission after 5 days of isolation following diagnosis or symptom onset is low.

3.
Oncologist ; 2022 Oct 11.
Article in English | MEDLINE | ID: covidwho-2062950

ABSTRACT

BACKGROUND: Coronavirus disease 2019 (COVID-19) pandemic affected millions of individuals, and patients with cancer are known to be more susceptible. Vaccines against SARS-CoV-2 have been developed and used for patients with cancer, but scarce data are available on their efficacy in patients under active anti-cancer therapies. MATERIALS AND METHODS: In this study, we semi-quantitatively measured the titers of the immunoglobulin G against the anti-spike protein subunit 1 of SARS-CoV-2 after vaccination of patients with early breast cancer undergoing concurrent chemotherapy, endocrinal or targeted non-cytotoxic treatments, and no treatments. RESULTS: Standard doses of COVID-19 vaccines provided sufficient immune responses in patients with early breast cancer, regardless of the type of anticancer therapies. However, the post-vaccination serum anti-spike antibody titers were significantly lower in the patients under cytotoxic chemotherapy. CONCLUSION: Our study emphasizes the importance of the personalized risk stratification and consideration for booster doses in more vulnerable populations.

6.
J Korean Med Sci ; 37(29): e238, 2022 Jul 25.
Article in English | MEDLINE | ID: covidwho-1963382

ABSTRACT

Despite the low prevalence of secondary bacterial infection in coronavirus disease 2019 (COVID-19) patients, most of them were administered antibiotic therapy empirically. However, the prognostic impact of empirical antibiotic therapy has not been evaluated. We conducted retrospective propensity score-matched case-control study of 233 COVID-19 patients with moderate to severe illnesses who required oxygen therapy and evaluated whether empirical antibiotic therapy could improve clinical outcomes. Empirical antibiotic therapy did not improve clinical outcomes including length of stay, days with oxygen requirement, the proportion of patients with increased oxygen demand, the proportion of patients who required mechanical ventilation, and overall mortality. This finding implies that routine administration of antibiotics for the treatment of COVID-19 is not essential and should be restricted.


Subject(s)
COVID-19 , Anti-Bacterial Agents/therapeutic use , Case-Control Studies , Humans , Oxygen/therapeutic use , Retrospective Studies
7.
Nat Genet ; 54(8): 1103-1116, 2022 08.
Article in English | MEDLINE | ID: covidwho-1931425

ABSTRACT

The chr12q24.13 locus encoding OAS1-OAS3 antiviral proteins has been associated with coronavirus disease 2019 (COVID-19) susceptibility. Here, we report genetic, functional and clinical insights into this locus in relation to COVID-19 severity. In our analysis of patients of European (n = 2,249) and African (n = 835) ancestries with hospitalized versus nonhospitalized COVID-19, the risk of hospitalized disease was associated with a common OAS1 haplotype, which was also associated with reduced severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) clearance in a clinical trial with pegIFN-λ1. Bioinformatic analyses and in vitro studies reveal the functional contribution of two associated OAS1 exonic variants comprising the risk haplotype. Derived human-specific alleles rs10774671-A and rs1131454 -A decrease OAS1 protein abundance through allele-specific regulation of splicing and nonsense-mediated decay (NMD). We conclude that decreased OAS1 expression due to a common haplotype contributes to COVID-19 severity. Our results provide insight into molecular mechanisms through which early treatment with interferons could accelerate SARS-CoV-2 clearance and mitigate against severe COVID-19.


Subject(s)
COVID-19 , 2',5'-Oligoadenylate Synthetase/genetics , 2',5'-Oligoadenylate Synthetase/metabolism , Alleles , COVID-19/genetics , Hospitalization , Humans , SARS-CoV-2/genetics
9.
BMC Med ; 20(1): 181, 2022 05 04.
Article in English | MEDLINE | ID: covidwho-1892212

ABSTRACT

BACKGROUND: Practical guidance is needed regarding the vaccination of coronavirus disease 2019 (COVID-19) convalescent individuals in resource-limited countries. It includes the number of vaccine doses that should be given to unvaccinated patients who experienced COVID-19 early in the pandemic. METHODS: We recruited COVID-19 convalescent individuals who received one or two doses of an mRNA vaccine within 6 or around 18 months after a diagnosis of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection. Their samples were assessed for IgG-binding or neutralizing activity and cell-mediated immune responses against SARS-CoV-2 wild-type and variants of concern. RESULTS: A total of 43 COVID-19 convalescent individuals were analyzed in the present study. The results showed that humoral and cellular immune responses against SARS-CoV-2 wild-type and variants of concern, including the Omicron variant, were comparable among patients vaccinated within 6 versus around 18 months. A second dose of vaccine did not significantly increase immune responses. CONCLUSION: One dose of mRNA vaccine should be considered sufficient to elicit a broad immune response even around 18 months after a COVID-19 diagnosis.


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Viral , COVID-19/prevention & control , COVID-19 Testing , COVID-19 Vaccines , Humans , Immunity, Cellular , RNA, Messenger/genetics , SARS-CoV-2/genetics , Vaccination , Vaccines, Synthetic , mRNA Vaccines
11.
J Infect Dis ; 226(7): 1224-1230, 2022 09 28.
Article in English | MEDLINE | ID: covidwho-1816122

ABSTRACT

BACKGROUND: Humoral immunity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may wane rapidly in persons recovered from mild coronavirus disease 2019 (COVID-19), but little is known about the longevity. METHODS: Serum samples were obtained 8, 12, and 18 months after infection from 20 patients with mild COVID-19. The binding activities of serum antibodies (immunoglobulin [Ig]A, IgG, and IgM) against SARS-CoV-2 antigens of the Wuhan-1 reference strain (wild-type) and the B.1.1.7, P.1, B.1.167.2, and B.1.1.529 variants were measured by enzyme-linked immunosorbent assays. Neutralizing antibody titers were measured using a cytopathic effect-based live virus neutralization assay. RESULTS: Serum IgA and IgG antibodies against spike or receptor-binding domain (RBD) protein of wild-type SARS-CoV-2 were detected for up to 18 months, and neutralizing antibodies persisted for 8 to 18 months after infection. However, any significant antibody responses against RBD proteins of SARS-CoV-2 variants were not observed, and median neutralizing antibody titers against the Delta variant at 8, 12, and 18 months were 8- to 11-fold lower than against wild-type viruses (P<.001). CONCLUSIONS: Humoral immunity persisted for up to 18 months after SARS-CoV-2 infection in patients with mild COVID-19. However, humoral immune activity against more recently circulating variants was reduced in this population.


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Neutralizing , Antibodies, Viral , Antibody Formation , Humans , Immunoglobulin A , Immunoglobulin G , Immunoglobulin M , Spike Glycoprotein, Coronavirus
12.
Front Immunol ; 13: 830433, 2022.
Article in English | MEDLINE | ID: covidwho-1785337

ABSTRACT

Background: Despite the fact of ongoing worldwide vaccination programs for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), understanding longevity, breadth, and type of immune response to coronavirus disease-19 (COVID-19) is still important to optimize the vaccination strategy and estimate the risk of reinfection. Therefore, we performed thorough immunological assessments 1 year post-COVID-19 with different severity. Methods: We analyzed peripheral blood mononuclear cells and plasma samples at 1 year post-COVID-19 in patients who experienced asymptomatic, mild, and severe illness to assess titers of various isotypes of antibodies (Abs) against SARS-CoV-2 antigens, phagocytic capability, and memory B- and T-cell responses. Findings: A total of 24 patients (7, 9, and 8 asymptomatic, mild, and severe patients, respectively) and eight healthy volunteers were included in this study. We firstly showed that disease severity is correlated with parameters of immune responses at 1 year post-COVID-19 that play an important role in protecting against reinfection with SARS-CoV-2, namely, the phagocytic capacity of Abs and memory B-cell responses. Interpretation: Various immune responses at 1 year post-COVID-19, particularly the phagocytic capacity and memory B-cell responses, were dependent on the severity of the prior COVID-19. Our data could provide a clue for a tailored vaccination strategy after natural infection according to the severity of COVID-19.


Subject(s)
COVID-19 , Antibodies, Viral , Humans , Immunity , Leukocytes, Mononuclear , Reinfection , SARS-CoV-2 , Severity of Illness Index
13.
J Korean Med Sci ; 37(8): e67, 2022 Feb 28.
Article in English | MEDLINE | ID: covidwho-1714984

ABSTRACT

We investigated the kinetics of the neutralizing antibody responses to the severe acute respiratory syndrome-coronavirus-2 delta variant over the course of 1 year in 16 patients infected at the beginning of the pandemic. In patients with severe disease, neutralizing responses to the delta variant were detectable, albeit at lower levels than responses to the wild type. Neutralizing responses to the delta variant were undetectable, however, in asymptomatic persons. This finding implies that the vaccination strategy for persons with past natural infection should depend on the severity of the previous infection.


Subject(s)
Antibodies, Neutralizing/blood , Antibodies, Viral/blood , COVID-19/immunology , SARS-CoV-2/immunology , Adult , Aged , COVID-19/prevention & control , COVID-19 Vaccines/immunology , Female , Humans , Kinetics , Male , Middle Aged , Severity of Illness Index , Vaccination , Young Adult
14.
Infect Chemother ; 53(4): 776-785, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1607076

ABSTRACT

BACKGROUND: Co-infection with bacteria and severe acute respiratory syndrome coronavirus 2 may result in greater use of healthcare resources and a poor prognosis. Therefore, early selection and use of optimal antibiotics are essential. The direct rapid antibiotic susceptibility test (dRAST) can detect antibiotic resistance within 6 h of a Gram smear result. This study aimed to assess the effectiveness of dRAST for improving early selection of appropriate antibiotics for coronavirus disease 2019 (COVID-19) patients with bacteremia. MATERIALS AND METHODS: This retrospective study included 96 blood culture-positive COVID-19 patients. Bacterial isolates and antimicrobial resistance profiles of each case were evaluated. Cases were divided into two groups based on whether they underwent conventional antibiotic susceptibility test (AST) or dRAST. The time to optimal targeted treatment for the two groups was investigated and compared. In addition, we examined the proportion of cases for which appropriate antibiotics were selected and broad spectrum antibiotics were administered at 72 h from blood sample collection. RESULTS: The mean time to optimal targeted antibiotic treatment was shorter for the dRAST group [55.7; standard deviation (SD), 28.7 vs. 92.3; SD, 51.1 h; P = 0.041]. The proportion of cases receiving optimal targeted antibiotics 72 h after blood collection for culture was higher [6/10 (60.0%) vs. 10/25 (40.0%)] and the percentage receiving broad spectrum antibiotics at 72 h was lower [6/10 (60.0%) vs. 19/25 (76.0%)] in the dRAST group than in the conventional AST group. In terms of microbiology profile, the contamination rate was high (35.5%) and multidrug-resistant strains were common (63.2%) in COVID-19 patients with bacteremia. CONCLUSION: Application of dRAST for selection of antibiotics to treat bacteremia in COVID-19 patients may enable earlier and optimal treatment. The high incidence of contamination and resistant organisms in blood cultures from COVID-19 patients suggest that dRAST may speed up appropriate targeted treatment.

15.
J Korean Med Sci ; 36(38): e274, 2021 Oct 04.
Article in English | MEDLINE | ID: covidwho-1450798

ABSTRACT

Applying work restrictions for asymptomatic healthcare personnel (HCP) with potential exposure to coronavirus disease 2019 (COVID-19) is recommended to prevent transmission from potentially contagious HCP to patients and other HCP. However, it can lead to understaffing, which threatens the safety of both patients and HCP. We evaluated 203 COVID-19 exposure events at a single tertiary hospital from January 2020 to June 2021. A total of 2,365 HCP were potentially exposed, and work restrictions were imposed on 320 HCP, leading to the loss of 3,311 working days. However, only one of the work-restricted HCP was confirmed with COVID-19. During the study period, the work restriction measures might be taken excessively compared to their benefit, so establishing more effective standards for work restriction is required.


Subject(s)
COVID-19/prevention & control , COVID-19/transmission , Health Personnel , Occupational Exposure/prevention & control , Occupational Health , Primary Prevention/methods , Humans , Republic of Korea , Retrospective Studies , SARS-CoV-2 , Workplace
16.
J Korean Med Sci ; 36(14): e101, 2021 Apr 12.
Article in English | MEDLINE | ID: covidwho-1181337

ABSTRACT

We evaluated the Standard Q COVID-19 Ag test for the diagnosis of coronavirus disease 2019 (COVID-19) compared to the reverse transcription-polymerase chain reaction (RT-PCR) test. We applied both tests to patients who were about to be hospitalized, had visited an emergency room, or had been admitted due to COVID-19 confirmed by RT-PCR. Two nasopharyngeal swabs were obtained; one was tested by RT-PCR and the other by the Standard Q COVID-19 Ag test. A total of 118 pairs of tests from 98 patients were performed between January 5 and 11, 2021. The overall sensitivity and specificity for detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) for the Standard Q COVID-19 Ag test compared to RT-PCR were 17.5% (95% confidence interval [CI], 8.8-32.0%) and 100% (95% CI, 95.3-100.0%). Analysis of the results using RT-PCR cycle thresholds of ≤ 30 or ≤ 25 increased the sensitivity to 26.9% (95% CI, 13.7-46.1%), and 41.1% (95% CI, 21.6-64.0%), respectively.


Subject(s)
Antigens, Viral/immunology , COVID-19 Testing , COVID-19/diagnosis , COVID-19/immunology , Emergency Service, Hospital , False Positive Reactions , Humans , Nasopharynx/virology , Predictive Value of Tests , Probability , Reference Standards , Reproducibility of Results , Reverse Transcriptase Polymerase Chain Reaction , Sensitivity and Specificity
17.
Infect Chemother ; 52(3): 352-359, 2020 Sep.
Article in English | MEDLINE | ID: covidwho-918285

ABSTRACT

BACKGROUND: Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection is not differentiated clinically from other respiratory infections, and intensive care units (ICUs) are vulnerable to in-hospital transmission due to interventions inducing respiratory aerosols. This study evaluated the effectiveness of universal SARS-CoV-2 screening in ICUs in terms of screened-out cases and reduction in anxiety of healthcare personnel (HCP). MATERIALS AND METHODS: This prospective single-armed observational study was conducted in 2 ICUs of a single hospital. The number of patients diagnosed with SARS-CoV-2 infection by the screening program and healthcare workers in ICUs that visited the SARS-CoV-2 screening clinic or infection clinic were investigated. RESULTS: During the 7-week study period, no positive screening case was reported among a total of 142 patients. Among 86 HCP in the ICUs, only 2 HCP sought medical consultation for SARS-CoV-2 infection during the initial 2 weeks. CONCLUSION: A universal screening program for SARS-CoV-2 infection in ICUs with the coordination of other countermeasures in the hospital was reasonably effective in preventing in-hospital transmission in a pandemic situation and making clinical practices and HCP stable.

18.
Infection & chemotherapy ; 2020.
Article in English | WHO COVID | ID: covidwho-737772

ABSTRACT

BACKGROUND: Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection is not differentiated clinically from other respiratory infections, and intensive care units (ICUs) are vulnerable to in-hospital transmission due to interventions inducing respiratory aerosols. This study evaluated the effectiveness of universal SARS-CoV-2 screening in ICUs in terms of screened-out cases and reduction in anxiety of healthcare personnel (HCP). MATERIALS AND METHODS: This prospective single-armed observational study was conducted in 2 ICUs of a single hospital. The number of patients diagnosed with SARS-CoV-2 infection by the screening program and healthcare workers in ICUs that visited the SARS-CoV-2 screening clinic or infection clinic were investigated. RESULTS: During the 7-week study period, no positive screening case was reported among a total of 142 patients. Among 86 HCP in the ICUs, only 2 HCP sought medical consultation for SARS-CoV-2 infection during the initial 2 weeks. CONCLUSION: A universal screening program for SARS-CoV-2 infection in ICUs with the coordination of other countermeasures in the hospital was reasonably effective in preventing in-hospital transmission in a pandemic situation and making clinical practices and HCP stable.

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