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Open forum infectious diseases ; 2021.
Article in English | EuropePMC | ID: covidwho-1602289


Background SARS-CoV-2 infection elicits varying degrees of protective immunity conferred by neutralizing antibodies (nAbs). Here, we report the persistence of nAb responses over 12 months after infection despite their decreasing trend noticed from 6 months. Methods The study included sera from 497 individuals who had been infected with SARS-CoV-2 between January and August 2020. Samples were collected at 6 and 12 months after onset. The titers of IgG to the viral nucleocapsid protein (NP) and receptor-binding domain of the spike protein (RBD) were measured by CLEIA. The nAb titer was determined using lentivirus-based pseudovirus or authentic virus. Results Antibody titers of NP-IgG, RBD-IgG, and nAbs were higher in severe and moderate cases than in mild cases at 12 months after onset. While the nAb levels were likely to confer adequate protection against wild-type viral infection, the neutralization activity to recently circulating variants in some of the mild cases (~30%) was undermined, implying the susceptibility to reinfection with the variants of concerns (VOCs). Conclusions COVID-19 convalescent individuals have robust humoral immunity even at 12 months after infection albeit that the medical history and background of patients could affect the function and dynamics of antibody response to the VOCs.

Preprint in English | EuropePMC | ID: ppcovidwho-296006


Introduction: Blood tests and computed tomography (CT) findings at diagnosis are widely used in daily clinical practice and can offer useful prognostic factors for coronavirus disease 2019. Methods: : We retrospectively evaluated 66 patients who underwent a blood test and CT between January 1 and May 31, 2020, and performed a propensity score-matched case-control study. Cases and controls were a severe respiratory failure group (non-rebreather mask, nasal high-flow, positive-pressure ventilation) and a non-severe respiratory failure group, matched at a ratio of 1:3 by propensity scores constructed by age, sex, and medical history. We compared groups for maximum body temperature up to diagnosis, laboratory findings, and CT findings in the matched cohort. Two-tailed P-values <0.05 were considered statistically significant. Results: : Nine cases and 27 controls were included in the matched cohort. Significant differences were seen in maximum body temperature up to diagnosis (p=0.0043), the number of shaded lobes (p=0.0434), amount of ground-glass opacity (GGO) in the total lung field (p=0.0071), amounts of GGO (p=0.0001), and consolidation (p=0.0036) in the upper lung field, and pleural effusion (p=0.0117). Conclusions: : Fever and CT findings (such as GGO and consolidation) may be prognostic indicators that can be easily measured at diagnosis.

Preprint in English | EuropePMC | ID: ppcovidwho-292710


Amid pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), vaccination is hailed as one of the most effective preventive measures. An mRNA vaccine termed BNT162b2 showed satisfactory safety and efficacy in the clinical trials but several issues including variability in the individual immune response or determination of target antibody titre that exerts sufficient immune protection needs to be assessed for planning a more efficient vaccination strategy. By monitoring IgG titres before and two months after the initial administration of BNT162b2 in 655 healthcare workers by Abbott IgG II quant that detects IgG against the receptor-binding domain in S protein of SARS-CoV-2, we confirmed that hypertension, dyslipidaemia, chronic kidney disease and use of immune suppressant in addition to male gender, advanced age, and absence of previous infection were significantly associated with low antibody response to the vaccination.

JPRN; 24/11/2021; TrialID: JPRN-jRCT2031210448
Clinical Trial Register | ICTRP | ID: ictrp-JPRN-jRCT2031210448



coronavirus disease-2019


A dose (2 mL) of JH509 or placebo is inhaled twice daily (morning and evening) for about 4 minutes using a Philips mesh nebulizer for seven days.

Primary outcome:

Rate of severe conditions with Score 3 or more serious on a seven-point ordinal scale from the start date of investigational drug administration (Day 1) to Day 28.


Inclusion criteria: 1. Written informed consent has been obtained from the participants with an age of over 20 years at the time of signing the informed consent.
2. SARS-CoV-2 infection is diagnosed by RT-PCR within 72 hours before starting drug administration.
3. Less than six days from onset of COVID-19-related symptoms below to starting the administration of the investigational drug with at least one of the following symptoms observed at the time of enrollment : fever (37.5C or higher), respiratory symptoms (cough, shortness of breath, sore throat, runny nose, etc.), headache, myalgia, malaise, abdominal pain, diarrhea, nausea/vomiting, dysosmia, dysgeusia, or other COVID-19 symptoms defined by investigators or subinvestigators.
4. Oxygen saturation (SpO2) measured by pulse oximeter is more than 95%.
5. Require no supplemental oxygen.
6. Women (less than 12 months after the last menstrual period) who have a negative pregnancy test (urine hCG qualification) and agree to use highly effective contraceptive methods (taking oral contraceptives or use of condom by male partner) during the study period. Investigators or subinvestigators will provide guidance on contraceptive methods.
7. Women who are not breast-feeding.

Exclusion criteria: 1. History of hypersensitivity to interferon or JH509 or any excipients of interferon or JH509.
2. Have received antiviral treatments and drugs expected to have antiviral effects (favipiravir, remdesivir, interferon, nafamostat mesilate, and casirivimab/imdevimab, including drugs that are being newly developed and that have been approved) in the past or having had it considered necessary to receive these treatments during the study period.
3. Having had it considered necessary to receive treatments, such as drugs containing corticosteroids (excluding topical drugs), antimicrobial agents, and inhalants other than the investigational drug during the study period.
4. Taking "Shosaikoto," an herbal medicine.
5. Neuropsychiatric disorder and autoimmune disorder.
6. CTCAE Grade 3 or higher liver dysfunction (ALT/AST > 5ULN) or renal dysfunction (eGFR < 30 mL/min/1.73 m2).
7. Active infections or other medical conditions that contraindicate inhalation therapy.
8. Having the complication of malignant tumor or a history of malignant tumor within 1 year before consent acquisition.
9. Inappropriate for inclusion in the clinical trial as determined by investigators or subinvestigators.

J Exp Med ; 218(12)2021 12 06.
Article in English | MEDLINE | ID: covidwho-1467277


Adaptive immunity is a fundamental component in controlling COVID-19. In this process, follicular helper T (Tfh) cells are a subset of CD4+ T cells that mediate the production of protective antibodies; however, the SARS-CoV-2 epitopes activating Tfh cells are not well characterized. Here, we identified and crystallized TCRs of public circulating Tfh (cTfh) clonotypes that are expanded in patients who have recovered from mild symptoms. These public clonotypes recognized the SARS-CoV-2 spike (S) epitopes conserved across emerging variants. The epitope of the most prevalent cTfh clonotype, S864-882, was presented by multiple HLAs and activated T cells in most healthy donors, suggesting that this S region is a universal T cell epitope useful for booster antigen. SARS-CoV-2-specific public cTfh clonotypes also cross-reacted with specific commensal bacteria. In this study, we identified conserved SARS-CoV-2 S epitopes that activate public cTfh clonotypes associated with mild symptoms.

COVID-19/immunology , Epitopes, T-Lymphocyte/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , T-Lymphocytes, Helper-Inducer/immunology , Adult , Antibodies, Viral/immunology , Female , HLA Antigens/immunology , Humans , Lymphocyte Activation , Male
J Exp Med ; 218(12)2021 12 06.
Article in English | MEDLINE | ID: covidwho-1462245


Broadly protective vaccines against SARS-related coronaviruses that may cause future outbreaks are urgently needed. The SARS-CoV-2 spike receptor-binding domain (RBD) comprises two regions, the core-RBD and the receptor-binding motif (RBM); the former is structurally conserved between SARS-CoV-2 and SARS-CoV. Here, in order to elicit humoral responses to the more conserved core-RBD, we introduced N-linked glycans onto RBM surfaces of the SARS-CoV-2 RBD and used them as immunogens in a mouse model. We found that glycan addition elicited higher proportions of the core-RBD-specific germinal center (GC) B cells and antibody responses, thereby manifesting significant neutralizing activity for SARS-CoV, SARS-CoV-2, and the bat WIV1-CoV. These results have implications for the design of SARS-like virus vaccines.

Antibodies, Viral/immunology , Broadly Neutralizing Antibodies/immunology , COVID-19/immunology , Polysaccharides/immunology , SARS Virus/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Amino Acid Motifs , Animals , COVID-19/genetics , COVID-19/prevention & control , COVID-19 Vaccines/genetics , COVID-19 Vaccines/immunology , Female , Humans , Male , Mice , Mice, Inbred BALB C , Polysaccharides/genetics , Protein Domains , SARS Virus/genetics , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics
J Microbiol Immunol Infect ; 2021 Sep 29.
Article in English | MEDLINE | ID: covidwho-1440211


BACKGROUND: Exact comprehension of the prevalence of SARS-CoV-2 infection is essential for the preventive measures. In the clinical settings, however, patients infected with SARS-CoV-2 may not be fully detected by PCR. In the long-term prevalence study, cut-off of IgG assay may not be appropriate due to waning IgG titer. METHODS: 24 PCR-negative subjects suspected of COVID-19 were categorized into cohorts termed "presumed COVID-19 positive" and "presumed COVID-19 negative" by chest CT images. IgG against nucleocapsid protein of SARS-CoV-2 (IgG (N)) and IgG against receptor biding domain of SARS-CoV-2 (IgG (RBD)) were measured in sera of the subjects and the concordance with the cohort categorization was assessed by receiver operating characteristics (ROC) analyses. RESULTS: Area under the curves (AUC's) by the ROC analyses with the 24 subjects were 0.982 with IgG (N) and 0.854 with IgG (RBD). Even when we excluded the subjects whose initial PCR was performed after five days from symptom onset, the AUC's were 0.967 with IgG (N) and 0.800 with IgG (RBD). The ROC analysis indicated 0.2 S/C as the optimum cut-off forIgG (N). CONCLUSION: Both IgG (N) and IgG (RBD) titers were significantly elevated in subjects whose PCR never showed positive but suggestive of SARS-CoV-2 infection, which indicated the necessity of serological tests in complementing the shortcomings of PCR. For a long-term prevalence study, a cut-off lower than the one used in the ongoing infection phase (e.g. 0.2 S/C vs. 1.4 S/C) was indicated to be more appropriate for IgG (N).

Infect Dis Ther ; 10(4): 2489-2509, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1375855


INTRODUCTION: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of coronavirus disease 2019 (COVID-19), is an enveloped, single-stranded RNA virus. Favipiravir is an orally administrable antiviral drug whose mechanism of action is to selectively inhibit RNA-dependent RNA polymerase. A preliminary trial in COVID-19 patients reported significant improvements across a multitude of clinical parameters, but these findings have not been confirmed in an adequate well-controlled trial. We conducted a randomized, single-blind, placebo-controlled Phase III trial assessing the efficacy and safety of favipiravir in patients with moderate pneumonia not requiring oxygen therapy. METHODS: COVID-19 patients with moderate pneumonia (SpO2 ≥ 94%) within 10 days of onset of fever (temperature ≥ 37.5 °C) were assigned to receive either placebo or favipiravir (1800 mg twice a day on Day 1, followed by 800 mg twice a day for up to 13 days) in a ratio of 1:2. An adaptive design was used to re-estimate the sample size. The primary endpoint was a composite outcome defined as the time to improvement in temperature, oxygen saturation levels (SpO2), and findings on chest imaging, and recovery to SARS-CoV-2-negative. This endpoint was re-examined by the Central Committee under blinded conditions. RESULTS: A total of 156 patients were randomized. The median time of the primary endpoint was 11.9 days in the favipiravir group and 14.7 days in the placebo group, with a significant difference (p = 0.0136). Favipiravir-treated patients with known risk factors such as obesity or coexisting conditions provided better effects. Furthermore, patients with early-onset in the favipiravir group showed higher odds ratio. No deaths were documented. Although adverse events in the favipiravir group were predominantly transient, the incidence was significantly higher. CONCLUSIONS: The results suggested favipiravir may be one of options for moderate COVID-19 pneumonia treatment. However, the risk of adverse events, including hyperuricemia, should be carefully considered. TRIAL REGISTRATION: number: JapicCTI-205238.

Immunity ; 54(8): 1841-1852.e4, 2021 08 10.
Article in English | MEDLINE | ID: covidwho-1293863


Antibody titers against SARS-CoV-2 slowly wane over time. Here, we examined how time affects antibody potency. To assess the impact of antibody maturation on durable neutralizing activity against original SARS-CoV-2 and emerging variants of concern (VOCs), we analyzed receptor binding domain (RBD)-specific IgG antibodies in convalescent plasma taken 1-10 months after SARS-CoV-2 infection. Longitudinal evaluation of total RBD IgG and neutralizing antibody revealed declining total antibody titers but improved neutralization potency per antibody to original SARS-CoV-2, indicative of antibody response maturation. Neutralization assays with authentic viruses revealed that early antibodies capable of neutralizing original SARS-CoV-2 had limited reactivity toward B.1.351 (501Y.V2) and P.1 (501Y.V3) variants. Antibodies from late convalescents exhibited increased neutralization potency to VOCs, suggesting persistence of cross-neutralizing antibodies in plasma. Thus, maturation of the antibody response to SARS-CoV-2 potentiates cross-neutralizing ability to circulating variants, suggesting that declining antibody titers may not be indicative of declining protection.

Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/immunology , COVID-19/virology , SARS-CoV-2/immunology , Antibodies, Monoclonal/immunology , Antibody Specificity , COVID-19/epidemiology , Humans , Immunoglobulin G , Neutralization Tests , SARS-CoV-2/genetics , Viral Load
Sci Rep ; 11(1): 10727, 2021 05 21.
Article in English | MEDLINE | ID: covidwho-1238019


Corticosteroids use in coronavirus disease 2019 (COVID-19) is controversial, especially in mild to severe patients who do not require invasive/noninvasive ventilation. Moreover, many factors remain unclear regarding the appropriate use of corticosteroids for COVID-19. In this context, this multicenter, retrospective, propensity score-matched study was launched to evaluate the efficacy of systemic corticosteroid administration for hospitalized patients with COVID-19 ranging in the degree of severity from mild to critically-ill disease. This multicenter, retrospective study enrolled consecutive hospitalized COVID-19 patients diagnosed January-April 2020 across 30 institutions in Japan. Clinical outcomes were compared for COVID-19 patients who received or did not receive corticosteroids, after adjusting for propensity scores. The primary endpoint was the odds ratio (OR) for improvement on a 7-point ordinal score on Day 15. Of 1092 COVID-19 patients analyzed, 118 patients were assigned to either the corticosteroid and non-corticosteroid group, after propensity score matching. At baseline, most patients did not require invasive/noninvasive ventilation (85.6% corticosteroid group vs. 89.8% non-corticosteroid group). The odds of improvement in a 7-point ordinal score on Day 15 was significantly lower for the corticosteroid versus non-corticosteroid group (OR, 0.611; 95% confidence interval [CI], 0.388-0.962; p = 0.034). The time to improvement in radiological findings was significantly shorter in the corticosteroid versus non-corticosteroid group (hazard ratio [HR], 1.758; 95% CI, 1.323-2.337; p < 0.001), regardless of baseline clinical status. The duration of invasive mechanical ventilation was shorter in corticosteroid versus non-corticosteroid group (HR, 1.466; 95% CI, 0.841-2.554; p = 0.177). Of the 106 patients who received methylprednisolone, the duration of invasive mechanical ventilation was significantly shorter in the pulse/semi-pulse versus standard dose group (HR, 2.831; 95% CI, 1.347-5.950; p = 0.006). In conclusion, corticosteroids for hospitalized patients with COVID-19 did not improve clinical status on Day 15, but reduced the time to improvement in radiological findings for all patients regardless of disease severity and also reduced the duration of invasive mechanical ventilation in patients who required intubation.Trial registration: This study was registered in the University hospital Medical Information Network Clinical Trials Registry on April 21, 2020 (ID: UMIN000040211).

Adrenal Cortex Hormones/administration & dosage , COVID-19/therapy , Hospitalization , Respiration, Artificial , SARS-CoV-2 , COVID-19/diagnostic imaging , COVID-19/pathology , Critical Illness , Female , Humans , Male , Middle Aged , Retrospective Studies
Respirol Case Rep ; 9(5): e00751, 2021 May.
Article in English | MEDLINE | ID: covidwho-1176311


When a chest computed tomography (CT) scan is performed in the diagnosis and treatment of coronavirus disease 2019 (COVID-19) pneumonia, the possibility of lung neoplasm should be kept in mind if the ground-glass nodule (GGN) shows features that are non-specific for viral infection, such as solitary nature, relative roundness, well-defined borders, and distance from the pleura.

Intern Med ; 60(1): 123-130, 2021.
Article in English | MEDLINE | ID: covidwho-1004553


Case 1: A 65-year-old man with novel coronavirus infection (COVID-19) complicated with acute respiratory failure. On admission, the patient was started on favipiravir and corticosteroid. However, due to a lack of significant improvement, he was introduced to mechanical ventilation and extracorporeal membrane oxygenation (ECMO). Although iliopsoas hematoma occurred as a complication, the patient recovered. Case 2: A 49-year-old man with COVID-19 had been started on favipiravir and corticosteroid. Due to progressive respiratory failure, the patient underwent mechanical ventilation and ECMO. The patient recovered without complications. We successfully treated these severe cases with a multimodal combination of pharmacological and non-pharmacological supportive therapy.

Adrenal Cortex Hormones/therapeutic use , Amides/therapeutic use , Antiviral Agents/therapeutic use , COVID-19/therapy , Extracorporeal Membrane Oxygenation , Methylprednisolone/therapeutic use , Pyrazines/therapeutic use , Respiration, Artificial , Aged , COVID-19/complications , Humans , Male , Middle Aged , Respiratory Insufficiency/therapy , Respiratory Insufficiency/virology , SARS-CoV-2
Intern Med ; 60(1): 31-37, 2021 Jan 01.
Article in English | MEDLINE | ID: covidwho-902223


Objective We aimed to clarify clinical and laboratory characteristics of coronavirus disease 2019 (COVID-19) patients, and further explore the features to detect COVID-19 pneumonia at the first visit to community-based hospitals. Methods Diagnoses of COVID-19 were based on positive results from real-time reverse-transcription polymerase chain reaction testing of nasopharyngeal-swab specimens. We retrospectively reviewed the medical records of patients showing positive results. The clinical characteristics and results of blood tests were compared between the patients with and without pneumonia. The risk factors associated with pneumonia were then evaluated by a multivariable analysis. Results The study cohort comprised 154 patients, including 117 patients (76.0%) with pneumonia at first visit. Significant differences were seen in age, the frequency of fever, tachycardia, desaturation (peripheral oxygen saturation ≤95%), any comorbidity, neutrocyte count and fraction, lymphocyte count and fraction, platelet count, lactate dehydrogenase (LDH), C-reactive protein (CRP), and fibrinogen between the patients with and without pneumonia. Using a multivariable analysis, CRP ≥0.3 mg/dL and fibrinogen >400 mg/dL were found to be associated with the presence of pneumonia. Conclusion Community-based settings for screening COVID-19 patients should perform chest X-ray and blood tests for white blood cell fractions, fibrinogen, LDH, and CRP. Of these, elevations in the CRP and fibrinogen levels could be critically associated with the presence of COVID-19 pneumonia.

COVID-19/diagnosis , Adult , Age Factors , C-Reactive Protein/analysis , COVID-19/blood , COVID-19 Nucleic Acid Testing , Female , Fever/virology , Fibrinogen/metabolism , Humans , Japan , L-Lactate Dehydrogenase/blood , Leukocyte Count , Lymphocyte Count , Male , Middle Aged , Neutrophils , Oximetry , Platelet Count , Retrospective Studies , Risk Factors , SARS-CoV-2 , Tachycardia/virology
J Infect Chemother ; 27(2): 379-383, 2021 Feb.
Article in English | MEDLINE | ID: covidwho-844273


A 49-year-old Japanese male was managed by mechanical ventilation due to coronavirus disease 2019 (COVID-19) pneumonia. Favipiravir as an antiviral therapy, and anti-inflammatory treatment were administered. SARS-CoV-2 RNA was detected in serum by the loop-mediated isothermal amplification (LAMP) method on Day 9; favipiravir treatment was continued. On Day 13, negative serum RNA was confirmed, followed by mechanical ventilation was removed. On Day 23, LAMP negative was confirmed in nasopharynx, after that the patient discharged on Day 27. We could treat successfully for severe COVID-19 pneumonia based on the LAMP method. We consider this method will be useful in COVID-19 treatment.

Amides/administration & dosage , Antiviral Agents/administration & dosage , COVID-19/drug therapy , Pyrazines/administration & dosage , RNA, Viral/blood , SARS-CoV-2/isolation & purification , COVID-19/diagnosis , COVID-19 Testing/methods , Humans , Male , Middle Aged , Molecular Diagnostic Techniques/methods , Nasopharynx/virology , Nucleic Acid Amplification Techniques/methods , Pneumonia, Viral/drug therapy , RNA, Viral/isolation & purification , Respiration, Artificial/methods , Treatment Outcome , Viremia/diagnosis