Characterization and antiviral susceptibility of SARS-CoV-2 Omicron BA.2.

The recent emergence of SARS-CoV-2 Omicron (B.1.1.529 lineage) variants possessing numerous mutations has raised concerns of decreased effectiveness of current vaccines, therapeutic monoclonal antibodies and antiviral drugs for COVID-19 against these variants1,2. The original Omicron lineage, BA.1, prevailed in many countries, but more recently, BA.2 has become dominant in at least 68 countries3. Here we evaluated the replicative ability and pathogenicity of authentic infectious BA.2 isolates in immunocompetent and human ACE2-expressing mice and hamsters. In contrast to recent data with chimeric, recombinant SARS-CoV-2 strains expressing the spike proteins of BA.1 and BA.2 on an ancestral WK-521 backbone4, we observed similar infectivity and pathogenicity in mice and hamsters for BA.2 and BA.1, and less pathogenicity compared with early SARS-CoV-2 strains. We also observed a marked and significant reduction in the neutralizing activity of plasma from individuals who had recovered from COVID-19 and vaccine recipients against BA.2 compared to ancestral and Delta variant strains. In addition, we found that some therapeutic monoclonal antibodies (REGN10987 plus REGN10933, COV2-2196 plus COV2-2130, and S309) and antiviral drugs (molnupiravir, nirmatrelvir and S-217622) can restrict viral infection in the respiratory organs of BA.2-infected hamsters. These findings suggest that the replication and pathogenicity of BA.2 is similar to that of BA.1 in rodents and that several therapeutic monoclonal antibodies and antiviral compounds are effective against Omicron BA.2 variants.

Single-pass generation of widely-tunable frequency-domain entangled photon pairs.

We demonstrate a technique that generates frequency-entangled photon pairs with strong polarization correlation by using a single-period nonlinear crystal and single pass configuration. The technique is based on the simultaneous occurrence of two spontaneous parametric down-conversion processes satisfying independent type-II collinear quasi-phase matching conditions in periodically poled stoichiometric lithium tantalate. The generated photon pairs exhibit non-degenerate Hong-Ou-Mandel interference, indicating the presence of quantum entanglement in the frequency domain. This method provides a light source capable of wide-range quantum sensing and quantum imaging or high-dimensional quantum processing.

Clinical trends among patients with asthma hospitalized for COVID-19 based on data from a nationwide database: an observational study.

BACKGROUND: While the prevalence of severe cases and mortality rate of coronavirus disease 2019 (COVID-19) appear to be reducing, the clinical characteristics and severity of hospitalized patients with asthma and COVID-19 remain largely unknown. This study aimed to examine the association of asthma with COVID-19 severity and mortality risk. METHODS: Data from the Japanese COVID-19 Registry Database were used to investigate the association between COVID-19 and asthma. This study focused on patients hospitalized for COVID-19 in 690 facilities from January 31, 2020, to December 31, 2022. Multivariate analysis using logistic regression was conducted to assess whether asthma, compared with other conditions, represents a risk factor for mortality and invasive mechanical ventilation after COVID-19. RESULTS: In total, 72,582 patients with COVID-19 were included in the analysis, of whom, 3731 were diagnosed with asthma. From January 2020 to June 2021, asthma showed no significant association with an increase in mortality (OR 0.837, 95% CI 0.639-1.080, p = 0.184) or invasive mechanical ventilation events (OR 1.084, 95% CI 0.878-1.326, p = 0.440). An analysis conducted after July 2021 yielded similar results. For patients with asthma, factors such as age, body-mass index, sex, and chronic kidney disease increased the risk of mechanical ventilation. However, non-vaccination status and high blood pressure increased the risk of mechanical ventilation during the second half of the study. CONCLUSION: Patients with asthma did not have an increased risk of mortality or mechanical ventilation due to COVID-19. However, patients with asthma had a higher risk of more severe COVID-19 due to factors such as advancing age, elevated body-mass index, chronic kidney disease, and non-vaccination.

Duration of Infectious Virus Shedding by SARS-CoV-2 Omicron Variant-Infected Vaccinees.

To determine virus shedding duration, we examined clinical samples collected from the upper respiratory tracts of persons infected with severe acute respiratory syndrome coronavirus 2 Omicron variant in Japan during November 29-December 18, 2021. Vaccinees with mild or asymptomatic infection shed infectious virus 6-9 days after onset or diagnosis, even after symptom resolution.

Nationwide survey of refractory asthma with bronchiectasis by inflammatory subtypes.

RATIONALE: Bronchiectasis and bronchiolitis are differential diagnoses of asthma; moreover, they are factors associated with worse asthma control. OBJECTIVE: We determined clinical courses of bronchiectasis/bronchiolitis-complicated asthma by inflammatory subtypes as well as factors affecting them. METHODS: We conducted a survey of refractory asthma with non-cystic fibrosis bronchiectasis/bronchiolitis in Japan. Cases were classified into three groups, based on the latest fractional exhaled NO (FeNO) level (32 ppb for the threshold) and blood eosinophil counts (320/µL for the threshold): high (type 2-high) or low (type 2-low) FeNO and eosinophil and high FeNO or eosinophil (type 2-intermediate). Clinical courses in groups and factors affecting them were analysed. RESULTS: In total, 216 cases from 81 facilities were reported, and 142 were stratified: 34, 40 and 68 into the type 2-high, -intermediate and -low groups, respectively. The frequency of bronchopneumonia and exacerbations requiring antibiotics and gram-negative bacteria detection rates were highest in the type 2-low group. Eighty-seven cases had paired latest and oldest available data of FeNO and eosinophil counts; they were analysed for inflammatory transition patterns. Among former type 2-high and -intermediate groups, 32% had recently transitioned to the -low group, to which relatively low FeNO in the past and oral corticosteroid use contributed. Lastly, in cases treated with moderate to high doses of inhaled corticosteroids, the frequencies of exacerbations requiring antibiotics were found to be higher in cases with more severe airway lesions and lower FeNO. CONCLUSIONS: Bronchiectasis/bronchiolitis-complicated refractory asthma is heterogeneous. In patients with sputum symptoms and low FeNO, airway colonisation of pathogenic bacteria and infectious episodes are common; thus, corticosteroids should be carefully used.

Neutralising activity and antibody titre in 10 patients with breakthrough infections of the SARS-CoV-2 Omicron variant in Japan.

The Omicron variant of severe acute respiratory syndrome coronavirus 2 has multiple amino acid mutations in its spike proteins, which may allow it to evade immunity elicited by vaccination. We examined the neutralising activity and S1-IgG titres in patients with breakthrough infections caused by the Omicron variant after two doses of vaccination. We found that neutralising activity was significantly lower for the Omicron variant than for the Wuhan strain. Two doses of vaccination might not induce sufficient neutralising activity for the Omicron variant.

Prolonged SARS-CoV-2 infection associated with long-term corticosteroid use in a patient with impaired B-cell immunity.

Corticosteroids are widely used to treat severe COVID-19, but in immunocompromised individuals, who are susceptible to persistent infection, long term corticosteroid use may delay viral clearance. We present a case of prolonged SARS-CoV-2 infection in a man with significantly impaired B-cell immunity due to non-Hodgkin lymphoma which had been treated with rituximab. SARS-CoV-2 shedding persisted, despite treatment with remdesivir. Viral sequencing confirmed the persistence of the same viral strain, ruling out the possibility of reinfection. Although SARS-CoV-2 IgG, IgA and IgM remained negative throughout the treatment period, after reduction of the corticosteroid dose, PCR became negative. Long-term corticosteroid treatment, especially in immunocompromised individuals, may result in suppression of cell-mediated immunity and prolonged SARS-CoV-2 infection.

Fatty liver on computed tomography scan on admission is a risk factor for severe coronavirus disease.

OBJECTIVES: To alleviate the overflow of coronavirus disease 2019 (COVID-19) patients in hospitals, less invasive and simple criteria are required to triage the patients. We evaluated the relationship between COVID-19 severity and fatty liver on plain computed tomography (CT) scan performed on admission. METHODS: In this retrospective cohort study, we considered all COVID-19 patients at a large tertiary care hospital between January 31 and August 31, 2020. COVID-19 severity was categorized into severe (moderate and severe) and non-severe (asymptomatic and mild) groups, based on the Japanese National COVID-19 guidelines. Fatty liver was detected on plain CT scan. Multivariate logistic regression analysis was performed to evaluate factors associated with severe COVID-19. RESULTS: Of 222 patients (median age: 52 years), 3.2%, 58.1%, 20.7%, and 18.0% presented with asymptomatic, mild, moderate, and severe COVID-19, respectively. Although 59.9% had no fatty liver on plain CT, mild, moderate, and severe fatty liver occurred in 13.1%, 18.9%, and 8.1%, respectively. Age and presence of fatty liver were significantly associated with severe COVID-19. CONCLUSION: Our study showed that fatty liver on plain CT scan on admission can become a risk factor for severe COVID-19. This finding may help clinicians to easily triage COVID-19 patients.

Factors associated with anti-SARS-CoV-2 IgG antibody production in patients convalescing from COVID-19.

INTRODUCTION: Among patients with coronavirus disease 2019 (COVID-19), the factors that affect anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody production remain unclear. This study aimed to identify such factors among patients convalescing from COVID-19. METHODS: This study comprised patients who had been diagnosed with COVID-19 between January 1 and June 30, 2020 and gave consent for anti-SARS-CoV-2 spike protein antibody measurement using enzyme-linked immunosorbent assay during their acute and/or convalescent phases. Factors related to elevated antibody titers and the relationship between the days from disease onset and the development of antibody titers were assessed. RESULTS: A total of 84 participants enrolled in the study. Nineteen participants had antibody titers measured during the convalescent phase only, and 65 participants had antibody titers measured during the acute and convalescent phases. The antibody titers peaked in weeks 5 and 6. The stepwise multivariate log-normal analysis revealed that male sex (P = 0.04), diabetes mellitus (P = 0.03), and high C-reactive protein levels during the disease course (P < 0.001) were associated with elevated IgG antibodies. Glucocorticoid use was not associated with antibody titers. CONCLUSION: The study found that high values of maximum CRP levels during the acute phase, male sex, and diabetes mellitus were associated with elevated antibody titers. Antibody titers tended to be highest in the first 5 or 6 weeks after the onset of symptoms.

External validation and update of prediction models for unfavorable outcomes in hospitalized patients with COVID-19 in Japan.

INTRODUCTION: Most of the currently used prognostic models for COVID-19 are based on Western cohorts, but it is unknown whether any are applicable to patients with COVID-19 in Japan. METHODS: This retrospective cohort study included 160 patients with COVID-19 who were admitted to the National Center for Global Health and Medicine between January 26, 2020 and July 25, 2020. We searched PubMed for prognostic models for COVID-19. The predicted outcome was initiation of respiratory support or death. Performance of the candidate models was evaluated according to discrimination and calibration. We recalibrated the intercept of each model with our data. We also updated each model by adding ß2-microglobulin (ß2MG) to the model and recalculating the intercept and the coefficient of ß2MG. RESULTS: Mean patient age was 49.8 years, 68% were male, 88.7% were Japanese. The study outcomes occurred in 15 patients, including two deaths. Two-hundred sixty-nine papers were screened, and four candidate prognostic models were assessed. The model of Bartoletti et al. had the highest area under receiver operating characteristic curve (AUC) (0.88; 95% confidence interval 0.81-0.96). All four models overestimated the probability of occurrence of the outcome. None of the four models showed statistically significant improvement in AUCs by adding ß2MG. CONCLUSIONS: Our results suggest that the existing prediction models for COVID-19 overestimate the probability of occurrence of unfavorable outcomes in a Japanese cohort. When applying a prediction model to a different cohort, it is desirable to evaluate its performance according to the prevalent health situation in that region.

Direct hemoperfusion using a polymyxin B-immobilized polystyrene column for COVID-19.

OBJECTIVE: To evaluate the efficacy and safety of direct hemoperfusion using a polymyxin B-immobilized polystyrene column (PMX-DHP) in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-positive pneumonia patients. METHODS: This study was a case series conducted at a designated infectious diseases hospital. Twelve SARS-CoV-2-positive patients with partial pressure of arterial oxygen/percentage of inspired oxygen (P/F) ratio < 300 were treated with PMX-DHP on two consecutive days each during hospitalization. We defined day 1 as the first day when PMX-DHP was performed. PMX-DHP efficacy was assessed on days 7 and 14 after the first treatment based on eight categories. Subsequently, improvement in P/F ratio and urinary biomarkers on days 4 and 8, malfunctions, and ventilator and extracorporeal membrane oxygenation avoidance rates were also evaluated. RESULTS: On day 14 after the first treatment, disease severity decreased in 58.3% of the patients. P/F ratio increased while urine ß2-microglobulin decreased on days 4 and 8. Cytokine measurement pre- and post-PMX-DHP revealed decreased levels of interleukin-6 and the factors involved in vascular endothelial injury, including vascular endothelial growth factor. Twenty-two PMX-DHPs were performed, of which seven and five PMX-DHPs led to increased inlet pressure and membrane coagulation, respectively. When the membranes coagulated, the circuitry needed to be reconfigured. Circuit problems were usually observed when D-dimer and fibrin degradation product levels were high before PMX-DHP. CONCLUSIONS: Future studies are expected to determine the therapeutic effect of PMX-DHP on COVID-19. Because of the relatively high risk of circuit coagulation, coagulation capacity should be assessed beforehand.

Mechanism of Periostin Production in Human Bronchial Smooth Muscle Cells.

BACKGROUND: Asthma is a chronic airway inflammatory disease characterized by airway remodeling, in which the bronchial smooth muscle (BSM) cells play an important role. Periostin, a biomarker that reflects Th2-driven inflammatory diseases such as asthma, may play an important role in the asthmatic airway. Although periostin is mainly produced in airway epithelial cells and fibroblasts after interleukin (IL)-13 stimulation, whether BSM cells produce periostin remains unclear. Therefore, we investigated periostin production in BSM cells and the mechanisms involved. METHODS: Human BSM cells were cultured, and the effect of IL-13 stimulation on periostin production was evaluated using quantitative polymerase chain reaction and enzyme-linked immunosorbent assay (ELISA). We evaluated the phosphorylation of signal transducer and activator of transcription factor 6 (STAT6), extracellular signal-regulated kinase (ERK)1/2, and Akt after IL-13 stimulation. Furthermore, using ELISA, we evaluated the influence of several phosphorylation inhibitors on periostin production. RESULTS: Periostin mRNA expression increased in a dose- and time-dependent manner after IL-13 stimulation; periostin production was induced 24 and 48 h after stimulation. IL-13 stimulation induced the phosphorylation of STAT6, ERK1/2, and Akt. IL-13-induced periostin production was attenuated by inhibiting STAT6 phosphorylation and strongly suppressed by inhibiting mitogen-activated protein kinase kinase 1/2 phosphorylation or phosphatidylinositol 3-kinase (PI3K) phosphorylation. CONCLUSIONS: BSM cells produced periostin after IL-13 stimulation, via the JAK/STAT6, ERK1/2, and PI3K/Akt pathways. Understanding the mechanism of periostin production in BSM cells may help to clarify asthma pathogenesis.

Comparison of the clinical effects of combined salmeterol/fluticasone delivered by dry powder or pressurized metered dose inhaler.

The salmeterol/fluticasone combination (SFC) inhaler is currently the most widely used maintenance drug for asthmatics worldwide. Although the effectiveness of SFC as either a dry powder inhaler (DPI) or a pressurized metered dose inhaler (pMDI) is well documented, there is limited data comparing the clinical efficacies of the two devices. To address this issue, we carried out a randomized crossover trial in which asthmatic patients (n = 47; mean age, 62.5 ± 16.5 years old) received a 12-week treatment of SFC DPI (50/250 µg twice daily) or SFC pMDI (four puffs of 25/125 µg daily). After a 4-week washout period, patients received another crossover treatment for 12 weeks. Respiratory resistance and reactance were measured by forced oscillation technique (MostGraph-01), spirometry, fractional exhaled nitric oxide (FeNO), and an asthma control test (ACT) every 4 weeks. The mean forced expiratory volume1.0 at the baseline was 2.16 ± 0.86 (L). Respiratory system resistance at 5 Hz (R5), the difference between R5 and R at 20 Hz (R5 - R20), and FeNO improved in both treatment groups, while reactance at 5 Hz (X5) and ACT score improved only in the pMDI group. In patients >70 years old (n = 21), R5, R5 - R20, ΔX5, and FeNO improved only in the pMDI group. These results suggest that SFC by pMDI produces a stronger anti-inflammatory and bronchodilatory effect even in patients whose asthma is well controlled by SFC delivered by DPI.

The impact of co-existing seasonal allergic rhinitis caused by Japanese Cedar Pollinosis (SAR-JCP) upon asthma control status.

BACKGROUND: Seasonal Allergic Rhinitis Caused by Japanese Cedar Pollinosis (SAR-JCP) is a most common allergic rhinitis, affecting about 40% in Japan, but the influence from SAR-JCP upon asthma is controversial. The purpose of this study is to investigate the effect of coexistence of SAR-JCP upon control status of asthma using SACRA (Self-Assessment of Allergic Rhinitis and Asthma Questionnaire). METHODS: The design was prospective, single-center, observational study. Asthmatic patients were classified into 3 groups, patients without rhinitis, those with perennial rhinitis or those with SAR-JCP from the results of SACRA. The control status of asthma were evaluated by Visual Analog Scale (VAS) in SACRA and Asthma Control Test (ACT) score. They were evaluated twice, from September to January (nonpollen-season) and February to April (pollen-season) and compared. RESULTS: 451 patients were enrolled and 325 cases (72%) were diagnosed as having comorbidity of rhinitis, among which 173 with only perennial rhinitis, while 152 with SAR-JCP. There was no significant difference in asthma control level measured by VAS and ACT score among 3 groups during nonpollen-season. The asthma control level measured by VAS (1.91-2.95) and ACT score (22.7-21.6) got worse during pollen-season among patients with SAR-JCP, even though 84% received treatment for rhinitis. Although it differed according to criteria, asthma control during pollen-season was impaired in 18-38% asthmatic patients with SAR-JCP. CONCLUSION: It is possible to minimize the influence of AR on asthma control by obtaining an accurate diagnosis and providing sufficient treatment for rhinitis.

Interstitial lung disease with multiple microgranulomas in chronic granulomatous disease.

BACKGROUND: Chronic granulomatous disease (CGD) is a primary immunodeficiency disease that is characterized by susceptibility to bacterial and fungal infections. CGD patients also suffer from immune regulatory disorders, such as CGD-associated bowel inflammation with granuloma, which could be caused by excessive inflammation without demonstrable infection. PURPOSE: We investigated the clinical manifestation of interstitial lung disease (ILD) resulting from excessive inflammation in X-linked CGD patients. METHODS: Pulmonary CT images and testing of serum KL-6 levels were performed to assess ILD in the patients. For this study, patients with pulmonary lesions due to demonstrable infections were excluded from among ILD patients. RESULTS: Among 33 CGD patients, four developed ILD; they had increased reticulo-nodular opacities on CT images and elevated serum KL-6 levels. Histopathological examinations revealed multiple homogeneous microgranulomas in the lesions of inflammatory cell infiltration. Mononuclear cells obtained from their pulmonary lesions produced higher amounts of inflammatory cytokines than the peripheral blood mononuclear cells of CGD patients, suggesting that the only infiltrating cells in the pulmonary lesions were activated and produced large amounts of inflammatory cytokines in ILD patients. Interestingly, an anti-inflammatory drug, such as a corticosteroid or thalidomide, but not anti-bacterial or anti-fungal drugs, improved CT image findings and reduced their KL-6 levels. CONCLUSIONS: CGD patients' daily exposures to inhaled antigens may induce excessive reactions with the production of inflammatory cytokines leading to the development of ILD with multiple microgranulomas, which could be due to an inadequate production of reactive oxygen species in CGD.

Secondary pulmonary alveolar proteinosis complicating myelodysplastic syndrome results in worsening of prognosis: a retrospective cohort study in Japan.

BACKGROUND: Secondary pulmonary alveolar proteinosis (sPAP) is a very rare lung disorder comprising approximately 10% of cases of acquired PAP. Hematological disorders are the most common underlying conditions of sPAP, of which 74% of cases demonstrate myelodysplastic syndrome (MDS). However, the impact of sPAP on the prognosis of underlying MDS remains unknown. The purpose of this study was to evaluate whether development of sPAP worsens the prognosis of MDS. METHODS: Thirty-one cases of sPAP and underlying MDS were retrospectively classified into mild and severe cases consisting of very low-/low-risk groups and intermediate-/high-/very high-risk groups at the time of diagnosis of MDS, according to the prognostic scoring system based on the World Health Organization classification. Next, we compared the characteristics, disease duration, cumulative survival, and prognostic factors of the groups. RESULTS: In contrast to previous reports on the prognosis of MDS, we found that the cumulative survival probability for mild MDS patients was similar to that in severe MDS patients. This is likely due to the poor prognosis of patients with mild MDS, whose 2-year survival rate was 46.2%. Notably, 75% and 62.5% of patients who died developed fatal infectious diseases and exacerbation of PAP, respectively, suggesting that the progression of PAP per se and/or PAP-associated infection contributed to poor prognosis. The use of corticosteroid therapy and a diffusing capacity of the lung for carbon monoxide of less than 44% were predictive of poor prognosis. CONCLUSION: Development of sPAP during the course of MDS may be an important adverse risk factor in prognosis of patients with mild MDS.

A comparison of long-term anti-inflammatory effect of two ICS/LABA combination inhalers; fix-dosed maintenance therapy with budesonide/formoterol and salmeterol/fluticasone.

BACKGROUND: The clinical usefulness of fixed-dose maintenance therapy with salmeterol/fluticasone (SFC) and budesonide/formoterol combination inhaler (BUD/FM) has been established, though evidence of the long-term anti-inflammatory effects of these 2 inhalers are limited. METHODS: Patients with moderate persistent adult asthma who had received SFC 50/250µg bid with well-control status were recruited. After switching to 8-week therapy with fixed-dose BUD/FM 4 puffs (640/18µg) (phase-1), patients chose either SFC or BUD/FM. FeNO and ACT score were evaluated every 8 weeks until the end of the 52-week treatment period for both treatment groups (phase-2). RESULTS: In total, 103 patients were examined: BUD/FM was chosen by 34 patients (BUD/FM group), while SFC was chosen by 23 (SFC group). Thirty-six received SFC consistently from the beginning of the study (control). Patients in the BUD/FM and SFC groups showed significant improvements in ACT scores and FeNO levels in phase-1; these beneficial effects persisted for 52 weeks in the BUD/FM group. On the other hand, in the SFC group, although the FeNO level decreased from 54.3 ± 26.4 ppb to 41.9 ± 18.3 ppb in phase-1, it increased to 54.5 ± 26.2 ppb, a level similar to the baseline prior to the beginning of BUD/FM therapy, at 8 weeks in phase-2, and remained at 50-odd ppb thereafter. CONCLUSIONS: These results suggest that maintenance therapy with fixed-dose BUD/FM is a useful treatment option exerting an airway anti-inflammatory effect for a period as long as 1 year, even for asthmatics who could not accomplish total control with SFC.

A case of type 2 diabetes mellitus with weight gain and worsening of glycemic management after tezepelumab administration for severe bronchial asthma.

Some cases of bronchial asthma are refractory to conventional therapies. As the pathogenesis of bronchial asthma has been clarified, new treatments, such as bronchial thermoplasty and biological drugs, have been developed. Tezepelumab, an anti-thymic stromal lymphopoietin antibody, has been reported to inhibit the exacerbation of severe asthma; however, its adverse effects on glucose metabolism have not yet been reported. We encountered a case of weight gain and worsening glycemic management in a patient with type 2 diabetes and refractory bronchial asthma after the initiation of tezepelumab treatment. It has been reported that the overexpression of thymic stromal lymphopoietin in mice resulted in an enhanced release of free fatty acids from adipose tissues and the liver; thus, the administration of anti-thymic stromal lymphopoietin antibodies in the present case might have caused obesity, fatty liver and lower glucose tolerance.

Relapse of COVID-19 and Viral Evolution in a Patient With Good Syndrome: A Case Report.

Delays in clearance and rapid evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been reported in immunocompromised patients. We encountered a case of recurrent, multi-mutational SARS-CoV-2 infection in a 40-year-old man with severe immunodeficiency due to Good syndrome. The patient had not received the SARS-CoV-2 vaccination. In August 2021, he was first admitted to the hospital owing to coronavirus disease 2019 (COVID-19) pneumonia and was administered dexamethasone, remdesivir, and baricitinib. Although his fever and respiratory condition improved once, chest computed tomography (CT) revealed extensive diffuse consolidation and ground-glass opacities (GGOs), and both methylprednisolone pulse therapy and tocilizumab yielded a limited effect. After a third course of remdesivir without immunosuppressants or steroids, the patient recovered, and he tested negative for SARS-CoV-2. On day 272 since the clinical onset, he was readmitted with dyspnea and mild fever due to a COVID-19 recurrence. He was infected with the Delta variant (AY.29), despite the Omicron (BA.2) variant being predominant at that time. During this admission, additional remdesivir and casirivimab/imdevimab yielded marked effects, and the SARS-CoV-2 quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) tests rapidly returned negative. Phylogenetic analysis demonstrated the accumulation of mutations, including those yielding remdesivir resistance, throughout the SARS-CoV-2 genome. Appropriate use of antivirals and monoclonal antibodies may aid in the recovery of patients with COVID-19 and immunodeficiency and in preventing the emergence of multi-mutational SARS-CoV-2 variants.