Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 17 de 17
Filter
1.
J Infect Chemother ; 28(7): 912-917, 2022 Jul.
Article in English | MEDLINE | ID: covidwho-1828880

ABSTRACT

INTRODUCTION: New treatment methods, such as REGN-CoV2, have been approved for patients with coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, the effect of the drug on the duration of infectious viral shedding and viral mutations is unknown. In this study, we investigated the clinical efficacy of REGN-CoV2 treatment in patients with mild to moderate disease and compared its antiviral effects against different strains of SARS-CoV-2. METHODS: Viral culture and PCR testing were performed on the pharyngeal swabs collected from 28 patients with COVID-19 who were admitted and treated at Hiroshima University Hospital during the study period. Of these, 23 patients were treated with REGN-CoV2. The patients were classified into the REGN-CoV2(+) and REGN-CoV2(-) groups, and the clinical course was compared between the groups. The 50% inhibitory concentrations (IC50) of REGN-CoV2 against the isolated virus strains were determined. RESULTS: After treatment with REGN-CoV2, the virus culture positivity rate was greatly reduced. The time to negative viral culture was significantly shorter in the REGN-CoV2(+) group than in the REGN-CoV2(-) group. In vitro evaluation of REGN-CoV2 against isolated virus strains also showed efficacy. CONCLUSIONS: REGN-CoV2 treatment was effective in patients with mild COVID-19 and could shorten the period of infectious viral shedding. This may be an important factor in preventing the spread of infection. It may be possible to revise the isolation period for patients with mild disease treated with REGN-CoV2.


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Monoclonal, Humanized/therapeutic use , Antibodies, Neutralizing , COVID-19/drug therapy , Drug Combinations , Humans , RNA, Viral , Virus Shedding
2.
Frontiers in pharmacology ; 13, 2022.
Article in English | EuropePMC | ID: covidwho-1787241

ABSTRACT

Several traditional Japanese Kampo formulas are known to have inhibitory effects on infections with viruses that cause respiratory symptoms. Although some herbs and their components have been reported to suppress SARS-CoV-2 replication in vitro, it is difficult to compare effective Kampo formulas because of the different methods used in studies. Thus, we carried out in vitro experiments on the suppression of SARS-CoV-2 infection by Kampo formulas and crude drugs used for the common cold to compare their suppressive effects on virus infection. After infecting VeroE6/TMPRSS2 cells with SARS-CoV-2, lysates of the Kampo formulas and crude drugs were added, and after 24 h, the infectious titer in the medium was measured by the TCID50 method. Maoto was the most effective among the Kampo formulas, and Ephedrae herba was the most effective among the constituent crude drugs. However, a comparison of the suppressive effects of Ephedrae herba and Kampo formulas containing Ephedrae herba showed that the suppressive effect on virus infection did not depend on the content of Ephedrae herba. Based on the results, we believe that the use of Maoto among Kampo formulas is suitable as a countermeasure against COVID-19.

3.
EuropePMC;
Preprint in English | EuropePMC | ID: ppcovidwho-327166

ABSTRACT

The outbreak of SARS-CoV-2 variant Omicron which harbors a striking number of mutations in the spike protein has been raising concerns about the effectiveness of vaccines and antibody treatment1. Here, we confirmed a substantial reduction in neutralizing potency against Omicron in all convalescent and vaccinated sera. However, we found that some people infected by the early strain show relatively higher neutralization to Omicron. From those B cells, we developed neutralizing antibodies inhibiting broad variants including Delta and Omicron. Unlike reported antibodies, one had an extremely large interface and widely covered receptor binding motif of spike, thereby interfering with diversified variants. Somatic mutations introduced by long-term germinal center reaction contributed to the key structure of antibodies and the universal interaction with spike variants. Recalling such rare B cells may confer sustainable protection against SARS-CoV-2 variants emerging one after another.

4.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-324404

ABSTRACT

Novel coronavirus disease 2019 (COVID-19) has emerged as a global pandemic with far-reaching societal impact. Here we demonstrate that Pin1 is a key cellular molecule necessary for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) propagation. In this study, siRNA-mediated silencing of Pin1 expression markedly suppressed the proliferation of SARS-CoV-2 in VeroE6/TMPRSS2 cells. In addition, several recently generated Pin1 inhibitors showed strong inhibitory effects on SARS-CoV-2 proliferation, measured by both viral mRNA and protein synthesis, and alleviated the cytopathic effect (CPE) on VeroE6/TMPRSS2 cells. One compound, termed H-77, was found to block SARS-CoV-2 proliferation at an EC 50 below 5 µM regardless of whether it was added to the culture medium prior to or after SARS-CoV-2 infection. The inhibition of viral N protein mRNA synthesis by H-77 implies that the molecular mechanism underlying SARS-CoV-2 inhibition is likely to be associated with viral gene transcription or earlier steps. Another Pin1 inhibitor, all-trans retinoic acid (ATRA)—a commercially available drug used to treat acute promyelocytic leukemia (APL) and which both activates the retinoic acid receptor and inhibits the activity of Pin1—similarly reduced the proliferation of SARS-CoV-2. Taken together, the results indicate that Pin1 inhibitors could serve as potential therapeutic agents for COVID-19.

5.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-318075

ABSTRACT

Ethanol is an effective disinfectant against the novel coronavirus SARS-CoV-2. However, its effective concentration has not been shown, and we therefore analyzed the effects of different concentrations of ethanol on SARS-CoV-2. When SARS-CoV-2 was treated with varying ethanol concentrations and examined for changes in infectivity, the ethanol concentration at which 99% of the infectious titers were reduced was 24.1%(w/w) [29.3%(v/v)]. For reference, ethanol susceptibility was also examined with other envelope viruses, including influenza virus, vesicular stomatitis virus in the family Rhabdoviridae , and Newcastle disease virus in the family Paramyxoviridae , and the 99% inhibitory concentrations were found to be 28.8%(w/w) [34.8%(v/v)], 24.0%(w/w) [29.2%(v/v)], and 13.3%(w/w) [16.4%(v/v)], respectively. Some differences from SARS-CoV-2 were observed, but the differences were not significant. It was concluded that ethanol at a concentration of 30%(w/w) [36.2%(v/v)] almost completely inactivates SARS-CoV-2.

6.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-318074

ABSTRACT

Background: Around 5% of patients with coronavirus disease ( COVID-19) caused by severe acute respiratory syndrome coronavirus 2 develop severe COVID-19. Severe COVID-19 requires respiratory management with mechanical ventilation and an extended period of treatment. Prolonged infectious virus shedding is a concern in severe COVID-19 cases, but few reports have examined the duration of infectious virus shedding. We investigated the duration of infectious virus shedding in patients transferred to Hiroshima University Hospital with severe COVID-19 requiring mechanical ventilation. Methods: Nasopharyngeal swab specimens were collected and analyzed using both viral culture and reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) tests between December 2020 and February 2021.Findings: Of the 23 patients tested, the percentage of those with positive test results at first specimen collection (the median number of days to first specimen collection after symptom onset was ten) on RT-qPCR and viral culture was 95 ·7% (n = 22) and 30·4% (n = 7), respectively. All six patients with positive viral culture test results who were followed-up tested negative by day 24 after symptom onset but remained positive on RT-qPCR. Specimen viral loads based on PCR testing did not decrease over time, but viral loads determined via culture tests loads decreased over time. The longest negative conversion time was observed in a dialysis patient on immunosuppressive drugs.Interpretation: This study indicated that patients with severe COVID-19 remain culture positive ≥ ten days after symptom onset. The work also suggests that immunosuppressed patients with severe COVID-19 could consider isolation for ≥ 20 days.Funding: NoneDeclaration of Interests: We declare no competing interests.Ethics Approval Statement: This research was approved by the Ethical Committee for Epidemiology of Hiroshima University (approval number: E-2157).

7.
Sci Rep ; 12(1): 2419, 2022 02 14.
Article in English | MEDLINE | ID: covidwho-1684100

ABSTRACT

This study aimed to develop the feasible and effective universal screening strategy of the notable SARS-CoV-2 variants by Sanger Sequencing Strategy and then practically applied it for mass screening in Hiroshima, Japan. A total of 734 samples from COVID-19 confirmed cases in Hiroshima were screened for the notable SARS-CoV-2 variants (B.1.1.7, B.1.351, P.1, B.1.617.2, B.1.617.1, C.37, B.1.1.529, etc.). The targeted spike region is amplified by nested RT-PCR using in-house designed primer set hCoV-Spike-A and standard amplification protocol. Additionally, randomly selected 96 samples were also amplified using primer sets hCoV-Spike-B and hCoV-Spike-C. The negative amplified samples were repeated for second attempt of amplification by volume-up protocol. Thereafter, the amplified products were assigned for Sanger sequencing using corresponding primers. The positive amplification rate of primer set hCoV-Spike-A, hCoV-Spike-B and hCoV-Spike-C were 87.3%, 83.3% and 93.8% respectively for standard protocol and increased to 99.6%, 95.8% and 96.9% after second attempt by volume-up protocol. The readiness of genome sequences was 96.9%, 100% and 100% respectively. Among 48 mutant isolates, 26 were B.1.1.7 (Alpha), 7 were E484K single mutation and the rest were other types of mutation. Moreover, 5 cluster cases with single mutation at N501S were firstly reported in Hiroshima. This study indicates the reliability and effectiveness of Sanger sequencing to screen large number of samples for the notable SARS-CoV-2 variants. Compared to the Next Generation Sequencing (NGS), our method introduces the feasible, universally applicable, and practically useful tool for identification of the emerging variants with less expensive and time consuming especially in those countries where the NGS is not practically available. Our method allows not only to identify the pre-existing variants but also to examine other rare type of mutation or newly emerged variants and is crucial for prevention and control of pandemic.


Subject(s)
COVID-19/diagnosis , Mass Screening/methods , SARS-CoV-2/genetics , Sequence Analysis, DNA/methods , Spike Glycoprotein, Coronavirus/genetics , Amino Acid Sequence , COVID-19/epidemiology , COVID-19/virology , Feasibility Studies , High-Throughput Nucleotide Sequencing/methods , Humans , Japan/epidemiology , Pandemics/prevention & control , Reproducibility of Results , SARS-CoV-2/physiology , Sensitivity and Specificity , Sequence Homology, Amino Acid
8.
J Med Virol ; 94(4): 1734-1737, 2022 04.
Article in English | MEDLINE | ID: covidwho-1568202

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral load dynamics in respiratory samples have been studied, but knowledge about changes in serial serum samples of infected patients in relation to their immunological response is lacking. We investigated the dynamics of SARS-CoV-2 viral load and antibody response in sequential serum of coronavirus disease 2019 (COVID-19) patients and attempted to culture the virus in the serum. A total of 81 sequential serum samples from 10 confirmed COVID-19 patients (5 with mild and 5 with moderate symptoms) were analyzed. Samples were collected during hospitalization and after discharge (median follow-up of 35 days). SARS-CoV-2 ribonucleic acid in the serum was detected by real-time polymerase chain reaction. Total antibody and IgG to SARS-CoV-2 Spike protein were analyzed by Chemiluminescent Immunoassays, and neutralizing antibodies were detected using a Surrogate Virus Neutralization Test. Viremia was observed in all cases at admission, and viral copy gradually dropped to undetectable levels in patients with mild symptoms but fluctuated and remained persistent in moderate cases. The viral culture of samples with the highest viral load for each patient did not show any cytopathic change. The antibody response was faster and higher in moderate cases. This study provides a basic clue for infectious severity-dependent immune response, viremia, and antibody acquisition pattern.


Subject(s)
COVID-19/immunology , COVID-19/virology , Viremia/immunology , Viremia/virology , Adult , Aged , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , Female , Follow-Up Studies , Humans , Immunoglobulin G/blood , Male , Middle Aged , RNA, Viral/blood , RNA, Viral/genetics , SARS-CoV-2/genetics , SARS-CoV-2/immunology , SARS-CoV-2/isolation & purification , Severity of Illness Index , Viral Load
9.
Nature ; 602(7896): 300-306, 2022 02.
Article in English | MEDLINE | ID: covidwho-1532072

ABSTRACT

During the current coronavirus disease 2019 (COVID-19) pandemic, a variety of mutations have accumulated in the viral genome of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and, at the time of writing, four variants of concern are considered to be potentially hazardous to human society1. The recently emerged B.1.617.2/Delta variant of concern is closely associated with the COVID-19 surge that occurred in India in the spring of 2021 (ref. 2). However, the virological properties of B.1.617.2/Delta remain unclear. Here we show that the B.1.617.2/Delta variant is highly fusogenic and notably more pathogenic than prototypic SARS-CoV-2 in infected hamsters. The P681R mutation in the spike protein, which is highly conserved in this lineage, facilitates cleavage of the spike protein and enhances viral fusogenicity. Moreover, we demonstrate that the P681R-bearing virus exhibits higher pathogenicity compared with its parental virus. Our data suggest that the P681R mutation is a hallmark of the virological phenotype of the B.1.617.2/Delta variant and is associated with enhanced pathogenicity.


Subject(s)
COVID-19/virology , Membrane Fusion , Mutation , SARS-CoV-2/genetics , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/genetics , Amino Acid Substitution , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/epidemiology , Cricetinae , Giant Cells/metabolism , Giant Cells/virology , Male , Mesocricetus , Phylogeny , SARS-CoV-2/immunology , SARS-CoV-2/metabolism , Virulence/genetics , Virus Replication
10.
Biocontrol Sci ; 26(3): 177-180, 2021.
Article in English | MEDLINE | ID: covidwho-1438814

ABSTRACT

Ethanol is an effective disinfectant against the novel coronavirus SARS-CoV-2. However, its effective concentration has not been shown, and we therefore analyzed the effects of different concentrations of ethanol on SARS-CoV-2. When SARS-CoV-2 was treated with varying ethanol concentrations and examined for changes in infectivity, the ethanol concentration at which 99% of the infectious titers were reduced was 24.1% (w/w) [29.3% (v/v)]. For reference, ethanol susceptibility was also examined with other envelope viruses, including influenza virus, vesicular stomatitis virus in the family Rhabdoviridae, and Newcastle disease virus in the family Paramyxoviridae, and the 99% inhibitory concentrations were found to be 28.8%(w/w) [34.8% (v/v)], 24.0% (w/w) [29.2% (v/v)], and 13.3% (w/w) [16.4% (v/v)], respectively. Some differences from SARS-CoV-2 were observed, but the differences were not significant. It was concluded that ethanol at a concentration of 30%(w/w) [36.2% (v/v)] almost completely inactivates SARS-CoV-2.


Subject(s)
Disinfectants/pharmacology , Ethanol/pharmacology , SARS-CoV-2/drug effects , COVID-19/virology , Disinfectants/analysis , Ethanol/analysis , Humans , SARS-CoV-2/growth & development , SARS-CoV-2/physiology , Virus Inactivation/drug effects , Viruses/drug effects , Viruses/growth & development
11.
Sci Rep ; 11(1): 18581, 2021 09 17.
Article in English | MEDLINE | ID: covidwho-1428903

ABSTRACT

Novel coronavirus disease 2019 (COVID-19) has emerged as a global pandemic with far-reaching societal impact. Here we demonstrate that Pin1 is a key cellular molecule necessary for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) propagation. In this study, siRNA-mediated silencing of Pin1 expression markedly suppressed the proliferation of SARS-CoV-2 in VeroE6/TMPRSS2 cells. In addition, several recently generated Pin1 inhibitors showed strong inhibitory effects on SARS-CoV-2 proliferation, measured by both viral mRNA and protein synthesis, and alleviated the cytopathic effect (CPE) on VeroE6/TMPRSS2 cells. One compound, termed H-77, was found to block SARS-CoV-2 proliferation at an EC50 below 5 µM regardless of whether it was added to the culture medium prior to or after SARS-CoV-2 infection. The inhibition of viral N protein mRNA synthesis by H-77 implies that the molecular mechanism underlying SARS-CoV-2 inhibition is likely to be associated with viral gene transcription or earlier steps. Another Pin1 inhibitor, all-trans retinoic acid (ATRA)-a commercially available drug used to treat acute promyelocytic leukemia (APL) and which both activates the retinoic acid receptor and inhibits the activity of Pin1-similarly reduced the proliferation of SARS-CoV-2. Taken together, the results indicate that Pin1 inhibitors could serve as potential therapeutic agents for COVID-19.


Subject(s)
COVID-19/virology , NIMA-Interacting Peptidylprolyl Isomerase/metabolism , SARS-CoV-2/metabolism , Virus Replication/genetics , Animals , COVID-19/genetics , Chlorocebus aethiops , NIMA-Interacting Peptidylprolyl Isomerase/genetics , Pandemics , SARS-CoV-2/genetics , Vero Cells , Virus Internalization
12.
J Infect Chemother ; 28(1): 19-23, 2022 Jan.
Article in English | MEDLINE | ID: covidwho-1401624

ABSTRACT

BACKGROUND: Approximately 5% of patients with coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 develop severe COVID-19. Severe COVID-19 requires respiratory management with mechanical ventilation and an extended period of treatment. Prolonged infectious virus shedding is a concern in severe COVID-19 cases, but few reports have examined the duration of infectious virus shedding. Therefore, we investigated the duration of infectious virus shedding in patients transferred to Hiroshima University Hospital with severe COVID-19 requiring mechanical ventilation. METHODS: Nasopharyngeal swab specimens were collected and analyzed using both viral culture and reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) tests between December 2020 and February 2021. RESULTS: Of the 23 patients tested, the proportions of those with positive test results at first specimen collection (the median number of days to first specimen collection after symptom onset was 10) on RT-qPCR and viral culture tests were 95·7% and 30·4%, respectively. All six patients with positive viral culture test results who were followed-up tested negative 24 days after symptom onset but remained positive on RT-qPCR. Viral loads based on PCR testing did not decrease over time, but those determined via culture tests decreased over time. The longest negative conversion time was observed in a dialysis patient on immunosuppressive drugs. CONCLUSIONS: This study indicated that patients with severe COVID-19 remain culture positive for ≥ 10 days after symptom onset. Additionally, immunosuppressed patients with severe COVID-19 could consider isolation for ≥ 20 days.


Subject(s)
COVID-19 , Humans , RNA, Viral/genetics , Respiration, Artificial , SARS-CoV-2 , Viral Load , Virus Shedding
13.
Int J Environ Res Public Health ; 18(17)2021 08 30.
Article in English | MEDLINE | ID: covidwho-1390601

ABSTRACT

With the widespread and increasing number of cases of Coronavirus Disease (2019) globally, countries have been taking preventive measures against this pandemic. However, there is no universal agreement across cultures on whether wearing face masks are an effective physical intervention against disease transmission. We investigated the relationship between mask wearing and COVID-19 among close contacts of COVID-19 patients in the Hiroshima Prefecture, Japan. In the Hiroshima Prefecture, a COVID-19 form adapted from the reporting form, "Japanese Surveillance in Post-Extreme Emergencies and Disasters", was developed to collect data from COVID-19 patients' close contacts under active epidemiological surveillance at Public Health Centers. The relative risk of COVID-19 for mask users versus non-mask users was calculated. A total of 820 interviewees were included in the analysis and 53.3% of them responded that they wore masks. Non-mask users were infected at a rate of 16.4%, while mask users were infected at a rate of 7.1%. Those who wore masks were infected at a rate of 0.4 times that of those who did not wear masks. (RR = 0.4, 95%CI = 0.3-0.6; Adjusted RR = 0.6, 95%CI = 0.3-0.9). These findings implied that COVID-19 could be avoided to a certain degree by wearing a mask.


Subject(s)
COVID-19 , Humans , Masks , Pandemics , Public Health , SARS-CoV-2
14.
Sci Rep ; 11(1): 16629, 2021 08 17.
Article in English | MEDLINE | ID: covidwho-1361646

ABSTRACT

Since understanding molecular mechanisms of SARS-CoV-2 infection is extremely important for developing effective therapies against COVID-19, we focused on the internalization mechanism of SARS-CoV-2 via ACE2. Although cigarette smoke is generally believed to be harmful to the pathogenesis of COVID-19, cigarette smoke extract (CSE) treatments were surprisingly found to suppress the expression of ACE2 in HepG2 cells. We thus tried to clarify the mechanism of CSE effects on expression of ACE2 in mammalian cells. Because RNA-seq analysis suggested that suppressive effects on ACE2 might be inversely correlated with induction of the genes regulated by aryl hydrocarbon receptor (AHR), the AHR agonists 6-formylindolo(3,2-b)carbazole (FICZ) and omeprazole (OMP) were tested to assess whether those treatments affected ACE2 expression. Both FICZ and OMP clearly suppressed ACE2 expression in a dose-dependent manner along with inducing CYP1A1. Knock-down experiments indicated a reduction of ACE2 by FICZ treatment in an AHR-dependent manner. Finally, treatments of AHR agonists inhibited SARS-CoV-2 infection into Vero E6 cells as determined with immunoblotting analyses detecting SARS-CoV-2 specific nucleocapsid protein. We here demonstrate that treatment with AHR agonists, including FICZ, and OMP, decreases expression of ACE2 via AHR activation, resulting in suppression of SARS-CoV-2 infection in mammalian cells.


Subject(s)
Angiotensin-Converting Enzyme 2/antagonists & inhibitors , Basic Helix-Loop-Helix Transcription Factors/agonists , COVID-19/drug therapy , Carbazoles/pharmacology , Omeprazole/pharmacology , Receptors, Aryl Hydrocarbon/agonists , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/metabolism , Animals , Basic Helix-Loop-Helix Transcription Factors/metabolism , COVID-19/virology , Carbazoles/therapeutic use , Chlorocebus aethiops , Cytochrome P-450 CYP1A1/metabolism , Dose-Response Relationship, Drug , Drug Evaluation, Preclinical , Gene Expression Regulation/drug effects , Gene Knockdown Techniques , Hep G2 Cells , Humans , Omeprazole/therapeutic use , RNA-Seq , Receptors, Aryl Hydrocarbon/metabolism , SARS-CoV-2/drug effects , SARS-CoV-2/pathogenicity , Signal Transduction/drug effects , Vero Cells , Virus Internalization/drug effects
15.
PLoS One ; 16(2): e0246383, 2021.
Article in English | MEDLINE | ID: covidwho-1067425

ABSTRACT

BACKGROUND: In this study, we performed molecular characterization of SARS-CoV-2 strains in Hiroshima and its mutation pattern between the first and second waves of the outbreak. METHOD: A total of 55 nasal swab samples from the first wave in Hiroshima and 13 from the second wave were examined quantitatively by RT-qPCR and qualitatively by nested PCR using specific primers. Four samples from each wave underwent next-generation sequencing and phylogenetic tree analysis including controls and all sequences retrieved in Japan from GISAID and GenBank. Subsequently, mutations were examined. RESULTS: Viral load ranged 7.85 × 101-1.42 × 108 copies/ml. Of 68 samples, one was Asian type-O, 65 were European type-GR, and 2 were undetectable. Phylogenetic tree analysis indicated that Japan was infected with various Asian strains (L, S, V, O) from January through April. By second week of March, European strains (G, GH, GR) had appeared, and GR strains became predominant after mid-March. The first case in Hiroshima was classified as Asian strain O, and the rest were GR strains. Then, second wave of GR strains appeared independently with 11-15 base mutations. Comparing the first- and second-wave GR strains, mutation rate was 1.17-1.36 × 10-3 base substitutions per site per year; in addition, amino acid changes occurred at S1361P and P3371S in ORF1a, A314V in ORF1b, and P151L in N. All seven GR strains were D614G variants with R202K and G203R mutations in N. A single-nucleotide insertion in ORF8 that causes a defect in ORF8 protein was found in one isolate (S66) from the second wave. CONCLUSION: Our findings reveal the evolutionary hierarchy of SARS-CoV-2 in Japan. The predominant D614G variants and a new form of ORF8 deletion in Hiroshima provide the clue for role of viral factor in local outbreaks of SARS-CoV-2.


Subject(s)
COVID-19/diagnosis , Mutation , SARS-CoV-2/genetics , Adult , Aged , Aged, 80 and over , COVID-19/epidemiology , Disease Outbreaks , Female , Genome, Viral , High-Throughput Nucleotide Sequencing , Humans , Japan/epidemiology , Male , Middle Aged , Phylogeny , SARS-CoV-2/isolation & purification , Young Adult
16.
Photodiagnosis Photodyn Ther ; 33: 102184, 2021 Mar.
Article in English | MEDLINE | ID: covidwho-1039523

ABSTRACT

BACKGROUND: The effectiveness of 222 nm ultraviolet (UV) C light for disinfecting surfaces contaminated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been reported. The aim of this study was to evaluate the effect of the intermittent irradiation of 222 nm UVC on SARS-CoV-2 and the fluence-dependent effect of 222 nm UVC irradiation on SARS-CoV-2 inactivation. METHODS: We experimented with 5 min continuous and intermittent irradiation for 0.1, 0.05, 0.013, and 0.003 mW/cm2 of 222 nm UVC to evaluate the differences in the effect of the continuous and intermittent irradiation of 222 nm UVC on SARS-CoV-2 inactivation. For intermittent irradiation, we followed the on-off irradiation cycles with every 10-s irradiation followed by a 380-s interval. Thereafter, we evaluated the effects of 0.1, 0.013, and 0.003 mW/cm2 222 nm UVC irradiation on SARS-CoV-2 contamination at UV fluences of 1, 2, and 3 mJ/cm2 at each irradiance. RESULTS: At each irradiance, no significant difference was observed in the log reduction of SARS-CoV-2 between continuous and intermittent irradiation. At each UV fluence, no significant difference was observed in the log reduction of SARS-CoV-2 among the three different irradiance levels. CONCLUSION: There was no significant difference between continuous and intermittent irradiation with 222 nm UVC with regards to SARS-CoV-2 inactivation. Moreover, 222 nm UVC inactivates SARS-CoV-2 in a fluence-dependent manner. The efficacy of 222-nm UVC irradiation in reducing the contamination of SARS-CoV-2 needs to be further evaluated in a real-world setting.


Subject(s)
Disinfection/methods , SARS-CoV-2/radiation effects , Ultraviolet Rays , Humans , Virus Inactivation
17.
Am J Infect Control ; 49(3): 299-301, 2021 03.
Article in English | MEDLINE | ID: covidwho-743831

ABSTRACT

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), has emerged as a serious threat to human health worldwide. Efficient disinfection of surfaces contaminated with SARS-CoV-2 may help prevent its spread. This study aimed to investigate the in vitro efficacy of 222-nm far-ultraviolet light (UVC) on the disinfection of SARS-CoV-2 surface contamination. METHODS: We investigated the titer of SARS-CoV-2 after UV irradiation (0.1 mW/cm2) at 222 nm for 10-300 seconds using the 50% tissue culture infectious dose (TCID50). In addition, we used quantitative reverse transcription polymerase chain reaction to quantify SARS-CoV-2 RNA under the same conditions. RESULTS: One and 3 mJ/cm2 of 222-nm UVC irradiation (0.1 mW/cm2 for 10 and 30 seconds) resulted in 88.5 and 99.7% reduction of viable SARS-CoV-2 based on the TCID50 assay, respectively. In contrast, the copy number of SARS-CoV-2 RNA did not change after UVC irradiation even after a 5-minute irradiation. CONCLUSIONS: This study shows the efficacy of 222-nm UVC irradiation against SARS-CoV-2 contamination in an in vitro experiment. Further evaluation of the safety and efficacy of 222-nm UVC irradiation in reducing the contamination of real-world surfaces and the potential transmission of SARS-CoV-2 is needed.


Subject(s)
Decontamination/methods , Disinfection/methods , RNA, Viral/radiation effects , SARS-CoV-2/radiation effects , Ultraviolet Rays , COVID-19/prevention & control , COVID-19/virology , Humans
SELECTION OF CITATIONS
SEARCH DETAIL