Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 20 de 28
Filter
1.
Sci Rep ; 12(1): 13491, 2022 Aug 05.
Article in English | MEDLINE | ID: covidwho-1978015

ABSTRACT

Knowledge of the factors affecting the difference in kinetics and longevity of the neutralizing antibody (nAb) response to SARS-CoV-2 is necessary to properly prioritize vaccination. In the present study, from March to December 2020, of the 143 patients who recovered from COVID-19, 87 underwent study visits scheduled every 3 months. Patient demographics and blood samples were collected followed by a plaque reduction neutralization test to analyze nAb titers. A linear mixed model was used to compare the effects of sex, age, and disease severity over time. Results demonstrated a gradual reduction in nAb titers over time with a significant decrease from 6 to 9 months post-COVID-19 infection (p < 0.001). In time-to-sex, age, and disease severity comparisons, reduction in nAb titers over time was unaffected by sex (p = 0.167), age (p = 0.188), or disease severity (p = 0.081). Additionally, the nAb titer was 1.46 times significantly higher in those aged ≥ 50 years than in those aged < 50 years (p = 0.036) irrespective of time Moreover, the nAb titer was 2.41 times higher in the moderate or above than that in the below moderate disease severity group (p < 0.001). However, no significant differences were observed in terms of sex (p = 0.300). Given the reduction in nAbs over time, maintaining protective neutralizing antibodies regardless of sex, age, or disease severity is needed.


Subject(s)
Antibodies, Neutralizing , COVID-19 , Antibodies, Viral , Humans , SARS-CoV-2 , Severity of Illness Index
2.
Science ; : eabp8337, 2022 Jul 26.
Article in English | MEDLINE | ID: covidwho-1962060

ABSTRACT

Understanding the circumstances that lead to pandemics is important for their prevention. Here, we analyze the genomic diversity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) early in the coronavirus disease 2019 (COVID-19) pandemic. We show that SARS-CoV-2 genomic diversity before February 2020 likely comprised only two distinct viral lineages, denoted A and B. Phylodynamic rooting methods, coupled with epidemic simulations, reveal that these lineages were the result of at least two separate cross-species transmission events into humans. The first zoonotic transmission likely involved lineage B viruses around 18 November 2019 (23 October-8 December), while the separate introduction of lineage A likely occurred within weeks of this event. These findings indicate that it is unlikely that SARS-CoV-2 circulated widely in humans prior to November 2019 and define the narrow window between when SARS-CoV-2 first jumped into humans and when the first cases of COVID-19 were reported. As with other coronaviruses, SARS-CoV-2 emergence likely resulted from multiple zoonotic events.

3.
Cell Rep ; 40(3): 111117, 2022 Jul 19.
Article in English | MEDLINE | ID: covidwho-1914214

ABSTRACT

As an enveloped virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) delivers its viral genome into host cells via fusion of the viral and cell membranes. Here, we show that ANO6/TMEM16F-mediated cell surface exposure of phosphatidylserine is critical for SARS-CoV-2 entry and that ANO6-selective inhibitors are effective against SARS-CoV-2 infections. Application of the SARS-CoV-2 Spike pseudotyped virus (SARS2-PsV) evokes a cytosolic Ca2+ elevation and ANO6-dependent phosphatidylserine externalization in ACE2/TMPRSS2-positive mammalian cells. A high-throughput screening of drug-like chemical libraries identifies three different structural classes of chemicals showing ANO6 inhibitory effects. Among them, A6-001 displays the highest potency and ANO6 selectivity and it inhibits the single-round infection of SARS2-PsV in ACE2/TMPRSS2-positive HEK 293T cells. More importantly, A6-001 strongly inhibits authentic SARS-CoV-2-induced phosphatidylserine scrambling and SARS-CoV-2 viral replications in Vero, Calu-3, and primarily cultured human nasal epithelial cells. These results provide mechanistic insights into the viral entry process and offer a potential target for pharmacological intervention to protect against coronavirus disease 2019 (COVID-19).


Subject(s)
COVID-19 , Angiotensin-Converting Enzyme 2 , Animals , Anoctamins , COVID-19/drug therapy , Humans , Mammals/metabolism , Phosphatidylserines , Phospholipid Transfer Proteins/metabolism , SARS-CoV-2 , Virus Internalization
4.
Lab Anim Res ; 38(1): 17, 2022 Jun 28.
Article in English | MEDLINE | ID: covidwho-1910369

ABSTRACT

BACKGROUND: As the number of large-scale studies involving multiple organizations producing data has steadily increased, an integrated system for a common interoperable format is needed. In response to the coronavirus disease 2019 (COVID-19) pandemic, a number of global efforts are underway to develop vaccines and therapeutics. We are therefore observing an explosion in the proliferation of COVID-19 data, and interoperability is highly requested in multiple institutions participating simultaneously in COVID-19 pandemic research. RESULTS: In this study, a laboratory information management system (LIMS) approach has been adopted to systemically manage various COVID-19 non-clinical trial data, including mortality, clinical signs, body weight, body temperature, organ weights, viral titer (viral replication and viral RNA), and multiorgan histopathology, from multiple institutions based on a web interface. The main aim of the implemented system is to integrate, standardize, and organize data collected from laboratories in multiple institutes for COVID-19 non-clinical efficacy testings. Six animal biosafety level 3 institutions proved the feasibility of our system. Substantial benefits were shown by maximizing collaborative high-quality non-clinical research. CONCLUSIONS: This LIMS platform can be used for future outbreaks, leading to accelerated medical product development through the systematic management of extensive data from non-clinical animal studies.

6.
JAMA Netw Open ; 5(5): e2213606, 2022 05 02.
Article in English | MEDLINE | ID: covidwho-1858512

ABSTRACT

Importance: Data are limited on whether patients with breakthrough COVID-19 infection have the potential to significantly contribute to the spread of SARS-CoV-2. Objective: To compare the secondary attack rate and infectious viral shedding kinetics of SARS-CoV-2 between fully vaccinated individuals (breakthrough infection group) and partially or unvaccinated individuals (nonbreakthrough infection group). Design, Setting, and Participants: This cohort study assessed secondary transmission by analyzing the epidemiologic data of health care workers, inpatients, and caregivers diagnosed with COVID-19 during hospitalization or residence in a tertiary care hospital between March 1, 2020, and November 6, 2021. To evaluate viral shedding kinetics, the genomic RNA of SARS-CoV-2 was measured using polymerase chain reaction and performed virus culture from daily saliva samples of individuals with mild COVID-19 infected with the Delta variant who were isolated in a community facility in Seoul, South Korea, between July 20 and August 20, 2021. Exposures: COVID-19 vaccination. Main Outcomes and Measures: The secondary attack rate and infectious viral shedding kinetics according to COVID-19 vaccination status. Results: A total of 173 individuals (median [IQR] age, 47 [32-59] years; 100 female [58%]) with COVID-19 were included in the secondary transmission study, of whom 50 (29%) had a breakthrough infection. Secondary transmission was significantly less common in the breakthrough infection group than in the nonbreakthrough infection group (3 of 43 [7%] vs 29 of 110 [26%]; P = .008). In the viral shedding kinetics study, 45 patients (median age, 37 years [IQR, 25-49 years]; 14 female [31%]) infected with the Delta variant were included, of whom 6 (13%) were fully vaccinated and 39 (87%) were partially or unvaccinated. Although the initial genomic viral load was comparable between the 2 groups, viable virus in cell culture was detected for a notably longer duration in partially vaccinated (8 days after symptom onset) or unvaccinated (10 days after symptom onset) individuals compared with fully vaccinated individuals (4 days after symptom onset). Conclusions and Relevance: In this cohort study, although the initial genomic viral load was similar between vaccinated and unvaccinated individuals, fully vaccinated individuals had a shorter duration of viable viral shedding and a lower secondary attack rate than partially vaccinated or unvaccinated individuals. Data from this study provide important evidence that despite the possibility of breakthrough infections, COVID-19 vaccinations remain critically useful for controlling the spread of SARS-CoV-2.


Subject(s)
COVID-19 , SARS-CoV-2 , Adult , COVID-19/epidemiology , COVID-19/prevention & control , COVID-19 Vaccines , Cohort Studies , Female , Humans , Kinetics , Middle Aged
7.
Clin Infect Dis ; 2022 Apr 01.
Article in English | MEDLINE | ID: covidwho-1852999

ABSTRACT

BACKGROUND: Data on the clinical and virological characteristics of the delta variant of SARS-CoV-2 are limited. This prospective cohort study compared the characteristics of the delta variant to other variants. METHODS: Adult patients with mild COVID-19 who agreed to daily saliva sampling at a community isolation facility in South Korea between July and August 2021 were enrolled. Scores of 28 COVID-19-related symptoms were recorded daily. The genomic RNA and subgenomic RNA from saliva samples were measured by real-time reverse-transcriptase-PCR. Cell cultures were performed on saliva samples with positive genomic RNA results. RESULTS: A total of 141 patients (delta group, n = 108 [77%]; non-delta group, n = 33 [23%]) were enrolled. Myalgia was more common in the delta group than in the non-delta group (52% vs. 27%, P = .03). Total symptom scores were significantly higher in the delta group between days 3 to 10 after symptom onset. Initial genomic RNA titers were similar between the two groups; however, during the late course of disease, genomic RNA titers were higher in the delta group. Negative conversion of subgenomic RNA was slower in the delta group (median 9 vs. 5 days; P < .001). The duration of viral shedding in terms of positive viral culture was also longer in the delta group (median 5 vs. 3 days; P = .002). CONCLUSIONS: COVID-19 patients infected with the delta variant exhibited prolonged viable viral shedding with more severe symptoms than those infected with non-delta variants.

8.
J Korean Med Sci ; 37(17): e133, 2022 May 02.
Article in English | MEDLINE | ID: covidwho-1834343

ABSTRACT

BACKGROUND: The potential for a nosocomial outbreak of coronavirus disease 2019 (COVID-19) from a fully vaccinated individual is largely unknown. METHODS: In 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. RESULTS: The 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. CONCLUSION: Transmission 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.


Subject(s)
COVID-19 , Cross Infection , COVID-19/epidemiology , ChAdOx1 nCoV-19 , Cross Infection/epidemiology , Cross Infection/prevention & control , Disease Outbreaks , Humans , Male , SARS-CoV-2/genetics
9.
J Microbiol ; 60(3): 308-320, 2022 Mar.
Article in English | MEDLINE | ID: covidwho-1782972

ABSTRACT

The three types of approved coronavirus disease 2019 (COVID-19) vaccines that have been emergency-use listed (EUL) by the World Health Organization are mRNA vaccines, adenovirus-vectored vaccines, and inactivated vaccines. Canonical vaccine developments usually take years or decades to be completed to commercialization; however, the EUL vaccines being used in the current situation comprise several COVID-19 vaccine candidates applied in studies and clinical settings across the world. The extraordinary circumstances of the COVID-19 pandemic have necessitated the emergency authorization of these EUL vaccines, which have been rapidly developed. Although the benefits of the EUL vaccines outweigh their adverse effects, there have been reports of rare but fatal cases directly associated with COVID-19 vaccinations. Thus, a reassessment of the immunological rationale underlying EUL vaccines in relation to COVID-19 caused by SARSCOV-2 virus infection is now required. In this review, we discuss the manifestations of COVID-19, immunologically projected effects of EUL vaccines, reported immune responses, informed issues related to COVID-19 vaccination, and the potential strategies for future vaccine use against antigenic variants.


Subject(s)
COVID-19 Vaccines , COVID-19 , COVID-19/prevention & control , Humans , Immunity , Pandemics , SARS-CoV-2
11.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-315037

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused the current COVID-19 global pandemic. Vaccines and therapeutics are urgently needed for this highly transmissible virus. In this study, we screened human monoclonal antibodies (mAbs) targeting the receptor binding domain (RBD) of the SARS-CoV-2 spike protein from an antibody library constructed from peripheral blood mononuclear cells of a COVID-19 convalescent patient. A potent neutralizing antibody, termed CT-P59, was identified and found to be effective against various SARS-CoV-2 isolates including the D614G spike protein variant without antibody-dependent enhancement effect. Complex crystal structure of CT-P59 Fab/SARS-CoV-2 RBD showed that CT-P59 blocks interaction regions of SARS-CoV-2 RBD for its cellular receptor, angiotensin converting enzyme 2 (ACE2). The binding orientation of CT-P59 is notably different from the previously reported neutralizing mAbs targeting SARS-CoV-2 RBD suggesting that CT-P59 can be a novel binder to SARS-CoV-2 RBD. Therapeutic effects of CT-P59 were evaluated in three animal models (ferret, hamster, and rhesus monkey), and a substantial reduction in viral titre along with alleviation of clinical symptoms was observed. These findings suggest that the human monoclonal antibody, CT-P59, is a promising therapeutic candidate for treatment of COVID-19.

12.
J Infect Dis ; 225(9): 1554-1560, 2022 05 04.
Article in English | MEDLINE | ID: covidwho-1621615

ABSTRACT

BACKGROUND: Recently, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission through exposure to aerosols has been suggested. Therefore, we investigated the possibility of aerosol SARS-CoV-2 transmission within an apartment complex where residents reported testing positive for SARS-CoV-2 despite having no direct contact with other SARS-CoV-2-infected people. METHODS: Information on symptom onset and exposure history of the patients was collected by global positioning system (GPS) tracking to investigate possible points of contact or spread. Samples collected from patients and from various areas of the complex were analyzed using RNA sequencing. Phylogenetic analysis was also performed. RESULTS: Of 19 people with confirmed SARS-CoV-2 infection, 5 reported no direct contact with other residents and were from apartments in the same vertical line. Eight environmental samples tested positive for the virus. Phylogenetic analyses revealed that 3 of the positive cases and 1 environmental sample belonged to the B.1.497 lineage. Additionally, 3 clinical specimens and 1 environmental sample from each floor of the complex had the same amino acid substitution in the ORF1ab region. CONCLUSIONS: SARS-CoV-2 transmission possibly occurs between different floors of an apartment building through aerosol transmission via nonfunctioning drain traps.


Subject(s)
COVID-19 , SARS-CoV-2 , Aerosols , Humans , Phylogeny , SARS-CoV-2/genetics
13.
Front Immunol ; 12: 778829, 2021.
Article in English | MEDLINE | ID: covidwho-1555677

ABSTRACT

Since the coronavirus disease outbreak in 2019, several antibody therapeutics have been developed to treat severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. Antibody therapeutics are effective in neutralizing the virus and reducing hospitalization in patients with mild and moderate infections. These therapeutics target the spike protein of SARS-CoV-2; however, emerging mutations in this protein reduce their efficiency. In this study, we developed a universal SARS-CoV-2 neutralizing antibody. We generated a humanized monoclonal antibody, MG1141A, against the receptor-binding domain of the spike protein through traditional mouse immunization. We confirmed that MG1141A could effectively neutralize live viruses, with an EC50 of 92 pM, and that it exhibited effective Fc-mediated functions. Additionally, it retained its neutralizing activity against the alpha (UK), beta (South Africa), and gamma (Brazil) variants of SARS-CoV-2. Taken together, our study contributes to the development of a novel antibody therapeutic approach, which can effectively combat emerging SARS-CoV-2 mutations.


Subject(s)
Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/therapy , SARS-CoV-2/immunology , Animals , Antibodies, Monoclonal/therapeutic use , Antibodies, Neutralizing/therapeutic use , Antibodies, Viral/therapeutic use , Antibody Affinity , Complementarity Determining Regions/chemistry , Epitopes , Humans , Immunization , Mice , Molecular Docking Simulation , Protein Interaction Domains and Motifs , Receptors, IgG/immunology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology
14.
Diagnostics (Basel) ; 11(12)2021 Nov 25.
Article in English | MEDLINE | ID: covidwho-1542446

ABSTRACT

Rapid and accurate measurement of SARS-CoV-2 neutralizing antibodies (nAbs) can aid in understanding the development of immunity against COVID-19. This study evaluated the diagnostic performance of a rapid SARS-CoV-2 nAb detection test called the BZ COVID-19 nAb test BZ-nAb (BZ-nAb; BioZentech). Using the 90% plaque-reduction neutralization test (PRNT-90) as a reference, 104 serum specimens collected from COVID-19-positive and -negative patients were grouped into 40 PRNT-90-positive and 64 PRNT-90-negative specimens. The performance of the BZ-nAb was compared with that of the cPass surrogate virus neutralization test (cPass sVNT; Genscript). The BZ-nAb showed a sensitivity ranging from 92.5%-95.0% and specificity ranging from 96.9%-100%, whereas cPass sVNT showed a sensitivity of 100% (95% confidence interval (CI) 90.5%-100%) and specificity of 98.4% (95% CI, 91.6%-100%). The dilution factor obtained with PRNT-90 showed a stronger correlation with the percent inhibition of cPass sVNT (r = 0.8660, p < 0.001) compared with the test and control line ratio (T/C ratio) of the BZ-nAb (r = -0.7089, p < 0.001). An almost perfect agreement was seen between the BZ-nAb and cPass sVNT results, with a strong negative correlation between the BZ-nAb T/C ratio and cPass sVNT percent inhibition (r = -0.8022, p < 0.001). In conclusion, the diagnostic performance of the BZ-nAb was comparable to that of the cPass sVNT, although the BZ-nAb had a slightly lower sensitivity.

15.
Viruses ; 13(11)2021 10 22.
Article in English | MEDLINE | ID: covidwho-1481021

ABSTRACT

We conducted a prospective cohort study at a community facility designated for the isolation of individuals with asymptomatic or mild COVID-19 between 10 January and 22 February 2021 to investigate the relationship of viral shedding with symptom changes of COVID-19. In total, 89 COVID-19 adult patients (12 asymptomatic, 16 presymptomatic, 61 symptomatic) were enrolled. Symptom scores, the genomic RNA and subgenomic RNA of SARS-CoV-2 from saliva samples with a cell culture were measured. Asymptomatic COVID-19 patients had a similar viral load to symptomatic patients during the early course of the disease, but exhibited a rapid decrease in viral load with the loss of infectivity. Subgenomic RNA and viable virus by cell culture in asymptomatic patients were detected only until 3 days after diagnosis, and the positivity of the subgenomic RNA and cell culture in symptomatic patients gradually decreased in both from 40% in the early disease course to 13% at 10 days and 4% at 8 days after the symptom onset, respectively. In conclusion, symptomatic patients have a high infectivity with high symptom scores during the early disease course and gradually lose infectivity depending on the symptom. Conversely, asymptomatic patients exhibit a rapid decrease in viral load with the loss of infectivity, despite a similar viral load during the early disease course.


Subject(s)
Asymptomatic Infections , COVID-19/virology , SARS-CoV-2/physiology , Virus Shedding , Adult , COVID-19/diagnosis , COVID-19/physiopathology , COVID-19 Nucleic Acid Testing , Female , Humans , Male , Middle Aged , Prospective Studies , RNA, Viral/analysis , SARS-CoV-2/isolation & purification , Saliva/virology , Viral Load
16.
Nat Commun ; 12(1): 5120, 2021 08 25.
Article in English | MEDLINE | ID: covidwho-1373414

ABSTRACT

COVID-19 is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which infected >200 million people resulting in >4 million deaths. However, temporal landscape of the SARS-CoV-2 translatome and its impact on the human genome remain unexplored. Here, we report a high-resolution atlas of the translatome and transcriptome of SARS-CoV-2 for various time points after infecting human cells. Intriguingly, substantial amount of SARS-CoV-2 translation initiates at a novel translation initiation site (TIS) located in the leader sequence, termed TIS-L. Since TIS-L is included in all the genomic and subgenomic RNAs, the SARS-CoV-2 translatome may be regulated by a sophisticated interplay between TIS-L and downstream TISs. TIS-L functions as a strong translation enhancer for ORF S, and as translation suppressors for most of the other ORFs. Our global temporal atlas provides compelling insight into unique regulation of the SARS-CoV-2 translatome and helps comprehensively evaluate its impact on the human genome.


Subject(s)
COVID-19/virology , Protein Biosynthesis , SARS-CoV-2/genetics , Transcriptome , Gene Expression Regulation, Viral , Genome, Human , Humans , Open Reading Frames , RNA, Viral/genetics , RNA, Viral/metabolism , SARS-CoV-2/metabolism , Viral Proteins/genetics , Viral Proteins/metabolism
17.
J Korean Med Sci ; 36(33): e233, 2021 Aug 23.
Article in English | MEDLINE | ID: covidwho-1370979

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission among non-close contacts is not infrequent. We evaluated the proportion and circumstances of individuals to whom SARS-CoV-2 was transmitted without close contact with the index patient in a nosocomial outbreak in a tertiary care hospital in Korea. From March 2020 to March 2021, there were 36 secondary cases from 14 SARS-CoV-2 infected individuals. Of the 36 secondary cases, 26 (72%) had been classified as close contact and the remaining 10 (28%) were classified as non-close contact. Of the 10 non-close contact, 4 had short conversations with both individuals masked, 4 shared a space without any conversation with both masked, and the remaining 2 entered the space after the index had left. At least one quarter of SARS-CoV-2 transmissions occurred among non-close contacts. The definition of close contact for SARS-CoV-2 exposure based on the mode of droplet transmission should be revised to reflect the airborne nature of SARS-CoV-2 transmission.


Subject(s)
COVID-19/transmission , SARS-CoV-2 , COVID-19/epidemiology , Contact Tracing , Humans , Republic of Korea/epidemiology
18.
Clin Microbiol Infect ; 28(1): 101-106, 2022 Jan.
Article in English | MEDLINE | ID: covidwho-1356179

ABSTRACT

OBJECTIVES: The development of a rapid diagnostic test for viable SARS-CoV-2 is important for infection control. Real-time RT-PCR assays detect non-viable virus, and cell culture differentiates viable virus but it takes several weeks and is labour-intensive. Subgenomic RNAs may reflect replication-competent virus. We therefore evaluated the usefulness of subgenomic RNAs for diagnosing viable SARS-CoV-2 in patients with COVID-19. METHODS: Patients with various severities of confirmed COVID-19 were enrolled at a tertiary hospital between February and December 2020. RT-PCR assay results for genomic and subgenomic RNA of SARS-CoV-2 from nasopharyngeal swab, sputum and saliva specimens were compared with cell culture results. RESULTS: A total 189 specimens from 20 COVID-19 patients were tested in genomic and subgenomic PCR assays and cultured on Vero cells. Of these 189 samples, 62 (33%) gave positive culture results, 93 (49%) negative results and the remaining 34 (18%) indeterminate results. Compared with cell culture results, the sensitivities of genomic RNA and subgenomic RNA of the N and S genes were comparable at 100%, but the specificity of subgenomic RNA (N, 65% and S, 68%) was higher than that of genomic RNA (N, 23% and S, 17%, p < 0.001). The mean durations of positive culture and subgenomic RNA were 11.39 ± 10.34 and 13.75 ± 11.22 days after symptom onset (p 0.437), respectively, while that of genomic RNA was 22.85 ± 11.83 days after symptom onset (p < 0.001). DISCUSSION: Our comparison of subgenomic RNA detection with symptom duration and SARS-CoV-2 culture positivity provides a significant advancement on the transmissibility-based approach beyond the detection of SARS-CoV-2 genomic RNA, and warrants further studies on the development of better diagnostic strategy.


Subject(s)
COVID-19 Nucleic Acid Testing/methods , COVID-19 , RNA, Viral/isolation & purification , SARS-CoV-2 , Animals , COVID-19/diagnosis , Chlorocebus aethiops , Humans , Polymerase Chain Reaction , RNA, Viral/genetics , SARS-CoV-2/isolation & purification , Sensitivity and Specificity , Vero Cells
19.
Infect Chemother ; 53(2): 332-341, 2021 Jun.
Article in English | MEDLINE | ID: covidwho-1335280

ABSTRACT

BACKGROUND: Coronavirus disease 2019 (COVID-19) outbreaks occur in hospitals in many parts of the world. In hospital settings, the possibility of airborne transmission needs to be investigated thoroughly. MATERIALS AND METHODS: There was a nosocomial outbreak of COVID-19 in a hematologic ward in a tertiary hospital, Seoul, Korea. We found 11 patients and guardians with COVID-19 through vigorous contact tracing and closed-circuit television monitoring. We found one patient who probably had acquired COVID-19 through airborne-transmission. We performed airflow investigation with simulation software, whole-genome sequencing of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). RESULTS: Of the nine individuals with COVID-19 who had been in the hematologic ward, six stayed in one multi-patient room (Room 36), and other three stayed in different rooms (Room 1, 34, 35). Guardian in room 35 was close contact to cases in room 36, and patient in room 34 used the shared bathroom for teeth brushing 40 minutes after index used. Airflow simulation revealed that air was spread from the bathroom to the adjacent room 1 while patient in room 1 did not used the shared bathroom. Airflow was associated with poor ventilation in shared bathroom due to dysfunctioning air-exhaust, grill on the door of shared bathroom and the unintended negative pressure of adjacent room. CONCLUSION: Transmission of SARS-CoV-2 in the hematologic ward occurred rapidly in the multi-patient room and shared bathroom settings. In addition, there was a case of possible airborne transmission due to unexpected airflow.

20.
Yonsei Med J ; 62(7): 584-592, 2021 Jul.
Article in English | MEDLINE | ID: covidwho-1285268

ABSTRACT

PURPOSE: Neutralizing antibodies (NAbs) have been considered effective in preventing and treating viral infections. However, until now, the duration and clinical implications of antibody-mediated nature immunity in Koreans have remained unknown. Therefore, we examined NAbs levels and clinical characteristics in recovered coronavirus disease 2019 (COVID-19) patients. MATERIALS AND METHODS: Blood samples were collected from 143 adult patients who had been diagnosed with and had recovered from COVID-19 from February to March in 2020 at a tertiary-care university-affiliated hospital in Daegu, Korea. A plaque reduction neutralization test was conducted to analyze NAb titers. Individualized questionnaires were used to identify patient clinical information. RESULTS: The median number of days from symptom onset to the blood collection date was 109.0 (104.0; 115.0). The NAb titers ranged from 10 to 2560. The median NAb titer value was 40. Of the 143 patients, 68 (47.6%) patients had NAb titers ≥80, and 31 (21.7%) patients had NAb titers ≥160. The higher the age or disease severity, the higher the NAb titer. In univariate logistic regression, statistically significant predictors of high NAb titers (≥80) were age, myalgia, nausea or vomiting, dyspnea, and disease severity (p<0.05). Multivariable logistic regression showed that age ≥50 years (p=0.013) and moderate or higher disease severity (p<0.001) were factors associated with high NAb titers (≥80). None of the patients had reinfection of COVID-19. CONCLUSION: All recovered patients were found to have NAbs regardless of the NAb titers maintained by natural immunity. Age and disease severity during COVID-19 infection were associated with high NAb titers.


Subject(s)
COVID-19 , SARS-CoV-2 , Adult , Antibodies, Neutralizing , Antibodies, Viral , Humans , Middle Aged , Republic of Korea
SELECTION OF CITATIONS
SEARCH DETAIL