Efficacy of Bortezomib for Treating Anti-Interferon-Gamma Autoantibody-Associated Adult-Onset Immunodeficiency Syndrome.

BACKGROUND: Currently, there is no effective treatment for adult-onset immunodeficiency (AOID) syndrome with anti-interferon-gamma autoantibodies (anti-IFN-γ-auto-Abs). This study aimed to investigate the effectiveness of bortezomib (BTZ) for decreasing anti-IFN-γ-auto-Abs. METHODS: A pre- and post-intervention study was conducted from February 2017 through June 2019 at Siriraj Hospital (Bangkok, Thailand). Five patients were invited to receive once-weekly BTZ (1.3 mg/m2 body surface area) subcutaneously for 8 weeks followed by oral cyclophosphamide (1 mg/kg/d) for 4 months. The primary outcomes were the difference in antibody level at 8 and 48 weeks compared with baseline and the incidence of serious adverse events (AEs). The secondary outcome was the occurrence of opportunistic infections (OIs) during the 72 weeks after starting BTZ. RESULTS: The median patient age was 46 years (range, 34-53). All patients had 3-5 OIs prior to enrollment. All patients were receiving antimycobacterial agents for treatment of nontuberculous mycobacterial infection at enrollment. There was no significant difference in the mean optical density of auto-Abs at 8 weeks (3.73 ± 0.72) or 48 weeks (3.74 ± 0.53) compared with baseline (3.84 ± 0.49; P = .336 and P = .555, respectively). However, after serum dilution, the antibody titer nonsignificantly decreased 8-16 weeks after BTZ initiation (P = .345). Ten OIs were observed 24-72 weeks after BTZ initiation. CONCLUSIONS: Treatment with BTZ followed by cyclophosphamide yielded no significant decrease in antibody titer levels, and 10 OIs were observed during 24-72 weeks of BTZ treatment. No serious AEs were observed. Combining rituximab with BTZ is likely necessary to prevent generation of new autoantibody-producing plasma cells. Clinical Trials Registration. NCT03103555.

Invasive aspergillosis in liver transplant recipients in the current era.

Invasive aspergillosis (IA) is a rare but fatal disease among liver transplant recipients (LiTRs). We performed a multicenter 1:2 case-control study comparing LiTRs diagnosed with proven/probable IA and controls with no invasive fungal infection. We included 62 IA cases and 124 matched controls. Disseminated infection occurred only in 8 cases (13%). Twelve-week all-cause mortality of IA was 37%. In multivariate analyses, systemic antibiotic usage (adjusted odds ratio [aOR], 4.74; P = .03) and history of pneumonia (aOR, 48.7; P = .01) were identified as independent risk factors associated with the occurrence of IA. Moreover, reoperation (aOR, 5.99; P = .01), systemic antibiotic usage (aOR, 5.03; P = .04), and antimold prophylaxis (aOR, 11.9; P = .02) were identified as independent risk factors associated with the occurrence of early IA. Among IA cases, Aspergillus colonization (adjusted hazard ratio [aHR], 86.9; P < .001), intensive care unit stay (aHR, 3.67; P = .02), disseminated IA (aHR, 8.98; P < .001), and dialysis (aHR, 2.93; P = .001) were identified as independent risk factors associated with 12-week all-cause mortality, while recent receipt of tacrolimus (aHR, 0.11; P = .001) was protective. Mortality among LiTRs with IA remains high in the current era. The identified risk factors and protective factors may be useful for establishing robust targeted antimold prophylactic and appropriate treatment strategies against IA.

Donor-derived infections-Insights from Singapore, Japan, and Thailand.

BACKGROUND: Solid organ transplantation (SOT) has expanded significantly in Asia over past few decades. Donor-derived infections (DDIs) remain a significant concern as they may adversely impact transplant outcomes. We aim to review the existing regulatory frameworks, screening protocols, and management practices for DDIs in Asia. METHODS: We reached out to transplant infectious diseases experts in Asia to provide standardized data on annual SOT numbers, incidence of DDIs, regulatory frameworks, donor and recipient screening protocols, and DDI surveillance measures. We present the data from Singapore, Japan, and Thailand. RESULTS: Donor screening for HIV, hepatitis B, hepatitis C, and syphilis is mandatory in all countries. Additionally, Japan screens for HTLV-1 antibody due to its endemicity. We also reviewed the protocols for screening and prevention of endemic infections in Asia. Singapore is the only country implementing universal screening for all donors for dengue, Zika, and chikungunya via blood and urine RT-PCR. Strongyloidiasis screening is not routinely done, although some transplant centers empirically give ivermectin prophylaxis to organ recipients. Tuberculosis screening with a donor questionnaire and chest radiograph is common for deceased donors, and some centers do Interferon Gamma Release Assay test for living donors. We also found a significant gap in the surveillance and reporting of potential DDIs in Asia and the overall incidence of DDIs in Asia is unknown and likely underreported. CONCLUSION: The experiences of Singapore, Japan, and Thailand offer valuable insights into current practices and the unmet needs regarding a DDI registry and call for coordinated efforts to address this critical issue in the region.

Risk factors of invasive fungal infections in liver transplant recipients: A systematic review and meta-analysis.

Invasive fungal infections (IFIs) remain one of the most common infectious complications after organ transplantation, and liver transplant recipients (LTRs) have the highest mortality rate. However, risk factors associated with IFIs have only been evaluated in small single-center studies. We performed a meta-analysis by conducting a comprehensive search using Ovid MEDLINE, Ovid Embase, Cochrane database of systematic reviews, and Cochrane central register of controlled trials. All case-control and cohort studies evaluating risk factors for IFIs in adult LTRs were screened. Utilizing a random-effects model, a multivariate analysis was completed, and 28 studies were eligible for meta-analysis. Rates of IFIs ranged from 1.4% to 32.7%. Previous antibiotic use (OR 9.3; 95% CI 3.2-27.0) and bacterial infection (OR 4.3; 95% CI 2.1-8.6) were risk factors of invasive candidiasis. Yet for invasive aspergillosis, posttransplant renal replacement therapy (OR 9.2; 95% CI 4.2-20.4), reoperation (OR 8.0; 95% CI 2.9-21.7), and cytomegalovirus infection (OR 6.2; 95% CI 2.0-19.3) were risk factors. The top independent risk factors for IFIs during studies from 2010 to 2019 were previous fungal colonization (OR 9.19; 95% CI 4.92-17.16), reoperation (OR 5.45; 95% CI 2.93-10.15), and previous bacterial infections (OR 3.81; 95% CI 2.13-6.83). These risk factors may be targeted by antifungal prophylaxis in LTRs.

Hematogenous dissemination of pulmonary mucormycosis manifested as multiple subcutaneous nodules: a case report and review of the literature.

BACKGROUND: Disseminated mucormycosis presenting with multiple subcutaneous nodules is a rare condition with a poor prognosis, and delayed diagnosis and treatment is common. CASE PRESENTATION: We report a case of 64-year-old Thai woman with colorectal cancer who initially presented with Acinetobacter baumannii pneumonia and respiratory failure. Following 10 days after her admission to the intensive care unit, she developed hospital-acquired pneumonia. Five days later, multiple subcutaneous nodules appeared on both arms and both legs. Bronchoalveolar lavage and skin biopsy cultures both grew Mucor spp. She was diagnosed with disseminated mucormycosis and was treated with liposomal amphotericin B at a dose of 5 mg/kg/day. Despite treatment, our patient succumbed to septic shock and multiorgan failure on the third day after definitive diagnosis. CONCLUSIONS: This case demonstrates that the subcutaneous nodules caused by hematogenously disseminated mucormycosis are unusual in a patient with a solid tumor. Clinicians should be aware of this atypical presentation of mucormycosis in patients with solid tumors.

EQUAL Candida score, an effective tool for predicting the outcomes of Candida tropicalis candidaemia: A retrospective cohort study.

BACKGROUND: Candida tropicalis is the most common non-albicans Candida species found in Asia-Pacific countries, including Thailand. The pathogen is known for its great virulence, which causes a high case-fatality rate. Associations between case fatality and patient characteristics, infectious disease unit consultation and EQUAL Candida score were investigated. METHODS: This retrospective cohort study was conducted with 160 cases of C. tropicalis bloodstream infection between 2015 and 2019 at a single, large, tertiary centre in Thailand. Clinical characteristics, clinical presentations, patient outcomes (30-day case-fatality rate) and independent predictive factors were analysed. RESULTS: The 30-day case-fatality rate was 68.1%. The median of the EQUAL Candida score was 8. Independent factors for the prediction of case fatality were septic shock (hazard ratio, 1.84), the use of mechanical ventilation (hazard ratio, 2.03) and the EQUAL Candida score (hazard ratio, 0.75). CONCLUSIONS: The predictive factors for 30-day case fatality were septic shock, mechanical ventilation use and the EQUAL Candida score. It is recommended that the EQUAL score be considered for patients infected with C. tropicalis candidaemia to reduce the case-fatality rate.

Clinical Characteristics and Treatment Outcomes for Patients Infected with Mycobacterium haemophilum.

Mycobacterium haemophilum is a nontuberculous mycobacterium that can infect immunocompromised patients. Because of special conditions required for its culture, this bacterium is rarely reported and there are scarce data for long-term outcomes. We conducted a retrospective study at Siriraj Hospital, Bangkok, Thailand, during January 2012-September 2017. We studied 21 patients for which HIV infection was the most common concurrent condition. The most common organ involvement was skin and soft tissue (60%). Combination therapy with macrolides and fluoroquinolones resulted in a 60% cure rate for cutaneous infection; adding rifampin as a third drug for more severe cases resulted in modest (66%) cure rate. Efficacy of medical therapy in cutaneous, musculoskeletal, and ocular diseases was 80%, 50%, and 50%, respectively. All patients with central nervous system involvement showed treatment failures. Infections with M. haemophilum in HIV-infected patients were more likely to have central nervous system involvement and tended to have disseminated infections and less favorable outcomes.

Asymptomatic Histoplasma Pylephlebitis in an Orthotopic Liver Transplant Recipient: A Case Report and Literature Review.

Histoplasma capsulatum is one of the most common pathogenic dimorphic fungi in Thailand. Its usual clinical syndrome is progressive disseminated histoplasmosis, whereas isolated hepatic histoplasmosis is extremely rare. Here, we report the world's first reported case of hepatic histoplasmosis with pylephlebitis in a 45-year-old Thai male who underwent orthotopic liver transplantation due to hepatitis B cirrhosis. Histopathology of the recipient's liver showed infiltration of fungal organisms in portal vein and hepatic granulomas. Serum H. capsulatum antibody was positive, and molecular identification from the liver revealed the DNA of H. capsulatum.

Recent Progress in the Diagnosis of Pathogenic Candida Species in Blood Culture.

Candidemia has become an emerging invasive fungal disease. Prompt treatment with appropriate antifungal agent is crucial to reduce the mortality of candidemia. The conventional blood culture method, which is considered the gold standard for candidemia diagnosis, has a low sensitivity and is time-consuming to perform. Recently, several novel advanced diagnostic methods that have a higher sensitivity and a shorter turnaround time than the conventional blood culture method have been developed for the early detection of Candida in blood samples or in blood culture broth. Most of these newer methods were developed using various molecular techniques, such as matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, peptide nucleic acid fluorescence in situ hybridization, and a number of DNA-based techniques including in-house and commercial polymerase chain reactions. In this article, we review and summarize the novel molecular methods that have been recently used for the detection and identification of Candida organisms in blood specimens.

NOCARDIA BEIJINGENSIS BRAIN ABSCESS IN AN HIV INFECTED PATIENT: A FIRST CASE REPORT AND LITERATURE REVIEW.

We report here brain abscesses caused by Nocardia beijingensis in a 59-year-old-Thai male with human immunodeficiency virus (HIV) infection presenting with progressive right sided hemiparesis. A computed tomography scan of the brain showed multiple brain abscesses. A stereotactic brain biopsy and 16S rRNA sequencing showed Nocardia beijingensis. The patient was treated with trimethoprim-sulfamethoxazole and recovered completely. As far as we are aware, this is the first reported case of a brain abscess in an HIV infected patient due to Nocardia beijingensis.

Long-term multiple metabolic abnormalities among healthy and high-risk people following nonsevere COVID-19.

Few studies have identified the metabolic consequences of the post-acute phase of nonsevere COVID-19. This prospective study examined metabolic outcomes and associated factors in nonsevere, RT-PCR-confirmed COVID-19. The participants' metabolic parameters, the prevalence of long-term multiple metabolic abnormalities (≥ 2 components), and factors influencing the prevalence were assessed at 1, 3, and 6 months post-onset. Six hundred individuals (mean age 45.5 ± 14.5 years, 61.7% female, 38% high-risk individuals) with nonsevere COVID-19 attended at least one follow-up visit. The prevalence of worsening metabolic abnormalities was 26.0% for BMI, 43.2% for glucose, 40.5% for LDL-c, 19.1% for liver, and 14.8% for C-reactive protein. Except for lipids, metabolic-component abnormalities were more prevalent in high-risk hosts than in healthy individuals. The prevalence of multiple metabolic abnormalities at the 6-month follow-up was 41.3% and significantly higher in high-risk than healthy hosts (49.2% vs 36.5%; P = 0.007). Factors independently associated with a lower risk of these abnormalities were being female, having dyslipidemia, and receiving at least 3 doses of the COVID-19 vaccine. These findings suggest that multiple metabolic abnormalities are the long-term consequences of COVID-19. For both high-risk and healthy individuals with nonsevere COVID-19, healthcare providers should monitor metabolic profiles, encourage healthy behaviors, and ensure complete vaccination.

Dynamics of Antibody Responses after Asymptomatic and Mild to Moderate SARS-CoV-2 Infections: Real-World Data in a Resource-Limited Country.

The dynamics of humoral immune responses of patients after SARS-CoV-2 infection is unclear. This study prospectively observed changes in anti-receptor binding domain immunoglobulin G (anti-RBD IgG) and neutralizing antibodies against the Wuhan and Delta strains at 1, 3, and 6 months postinfection between October 2021 and May 2022. Demographic data, clinical characteristics, baseline parameters, and blood samples of participants were collected. Of 5059 SARS-CoV-2 infected adult patients, only 600 underwent assessment at least once between 3 and 6 months after symptom onset. Patients were categorized as immunocompetent (n = 566), immunocompromised (n = 14), or reinfected (n = 20). A booster dose of a COVID-19 vaccine was strongly associated with maintained or increased COVID-19 antibody levels. The booster dose was also more strongly associated with antibody responses than the primary vaccination series. Among patients receiving a booster dose of a mRNA vaccine or a heterologous regimen, antibody levels remained steady or even increased for 3 to 6 months after symptom onset compared with inactivated or viral vector vaccines. There was a strong correlation between anti-RBD IgG and neutralizing antibodies against the Delta variant. This study is relevant to resource-limited countries for administering COVID-19 vaccines 3 to 6 months after infection.

Efficacy and Safety of Antiviral Agents in Preventing Allograft Rejection Following CMV Prophylaxis in High-Risk Kidney Transplantation: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials.

Many antiviral agents have been studied in clinical trials for allograft rejection prevention following cytomegalovirus (CMV) prophylaxis in high-risk kidney transplant patients. However, data on the most effective and safest treatment are lacking. We conducted a systematic review and network meta-analysis to rank CMV prophylaxis agents for allograft rejection prevention following CMV prophylaxis in high-risk kidney transplant patients according to their efficacy and safety. We conducted searches on the MEDLINE, Embase, SCOPUS, and CENTRAL databases, as well as the reference lists of selected studies up to December 2021, for published and peer-reviewed randomized controlled trials assessing the efficacy of CMV prophylaxis agents in high-risk kidney transplant patients. Thirteen studies were independently selected by three reviewers and included post-kidney transplant patients indicated for CMV prophylaxis who had been randomized to receive prophylactic antiviral agents or standard of care. The reviewers independently extracted data from the included studies, and direct and network meta-analyses were applied to assess the study outcomes. The probability of efficacy and safety was evaluated, and the drugs were assigned a numerical ranking. We evaluated the risk of bias using the Cochrane Risk of Bias 2.0 tool. The primary outcome was an incidence of biopsy-proven acute rejection, whereas the secondary outcome was a composite of major adverse drug reactions. Each outcome referred to the definition provided in the original studies. Valganciclovir, valacyclovir, and ganciclovir were identified to significantly decrease the incidence of biopsy-proven acute rejection with pooled risk differences (RDs) of -20.53% (95% confidence interval [CI] = -36.09% to -4.98%), -19.3% (95% CI = -32.7% to -5.93%), and -10.4% (95% CI = -19.7% to -0.12%), respectively. The overall major adverse drug reaction was 5.7% without a significant difference when compared with placebo. Valganciclovir had the best combined efficacy and safety among the examined antiviral agents and was the most effective and safest antiviral agent overall for allograft rejection prevention following CMV prophylaxis. Valacyclovir was the optimal alternative antiviral agent for patients who were unable to tolerate intravenous ganciclovir or access oral valganciclovir as financial problem. However, compliance and dose-related toxicities should be closely monitored.

Risk factors of invasive fungal infections in lung transplant recipients: A systematic review and meta-analysis.

BACKGROUND: Invasive fungal infection (IFI) remains a common complication after lung transplantation, causing significant morbidity and mortality. We have attempted to quantify systematically risk factors of IFI in lung transplant recipients. METHODS: Studies were retrieved from Ovid MEDLINE, Ovid Embase, Cochrane database of systematic reviews and Cochrane central register of controlled trials. All case-control and cohort studies evaluating the risk factors of IFI in adult lung transplant recipients were screened. Two researchers reviewed and assessed all studies independently. We pooled the estimated effect of each factor associated with IFI by using a random effect model. RESULTS: Eight studies were included in the systematic review and 5 studies were eligible for the meta-analysis. Rates of IFI range from 8% to 33% in lung transplant recipients. Independent risk factors for invasive aspergillosis (IA) in lung transplantation include previous fungal colonization (odds ratio [OR] 2.44; 95% confidence interval [CI] 0.08-0.47), cytomegalovirus infection (OR 1.96; 95% CI 1.08-3.56), and single lung transplantation (OR 1.77; 95% CI 1.08-2.91). Pre-emptive antifungal therapy is a protective factor for IA in lung transplant (OR 0.2; 95% CI 0.08-0.47). CONCLUSION: Cytomegalovirus infection, previous fungal colonization and single lung transplantation independently increase the risk of IA in lung transplant recipients. Pre-emptive antifungal therapy is a protective factor for IA in the lung transplant population.

QuantiFERON-Cytomegalovirus Assay for Prediction of Cytomegalovirus Viremia in Kidney Transplant Recipients: Study From High Cytomegalovirus Seroprevalence Country.

Background: Early studies showed the utility of pretransplant QuantiFERON-Cytomegalovirus (QF-CMV) assays for CMV-disease prediction post kidney transplant (KT). However, recent data are conflicting. Methods: This prospective cohort study enrolled adult patients undergoing KT between July 2017 and May 2019. Patients with antithymocyte globulin therapy or negative pretransplant CMV IgG were excluded. QF-CMV assays were performed on transplantation day and one month thereafter, and CMV viral loads were obtained 1, 3, and 6 months posttransplantation. The primary outcome was CMV viremia within 6 months. The QF-CMV assay-posttransplant CMV viremia association was analyzed. Results: Fifty-five patients were enrolled (male, 58.2%; mean (SD) age, 46.5 (10.2) years). Fifty-two (94.5%) received CMV-seropositive donor kidneys. Over 6 months, 29 patients developed CMV viremia (52.7%), with 14 (25.5%) having significant viremia requiring antiviral therapy. The CMV-viremia incidence of patients with nonreactive and reactive baseline QF-CMV assays did not differ significantly (55.3% and 47.1%; p = 0.573). Among patients with reactive pretransplant QF-CMV assays, there was a trend toward a lower incidence of CMV viremia for those who were persistently reactive at 1 month after KTs, although there was no statistically significant difference (50% vs 83%; p = 0.132). Conclusions: Our study could not support the use of single-timepoint pretransplant or 1-month posttransplant QF-CMV assays as a predictor for posttransplant CMV viremia in CMV seropositive KT recipients. Investigation of the association between dynamic QF-CMV-status changes and CMV-viremia incidence are needed.

Safety and Efficacy of Ivermectin for the Prevention and Treatment of COVID-19: A Double-Blinded Randomized Placebo-Controlled Study.

The safety and efficacy of ivermectin for the prevention and treatment of COVID-19 are still controversial topics. From August to November 2021, we conducted a double-blinded, randomized controlled trial at Siriraj Hospital, Thailand. Eligible participants were adults ≥ 18 years with suspected COVID-19 who underwent a SARS-CoV-2 RT-PCR test. After enrollment, the participants were randomized to receive either ivermectin (400−600 µg/kg/d) or placebo once daily for 3 days. Among 983 participants, 536 (54.5%) with a negative RT-PCR result were enrolled in the prevention study, and 447 (45.5%) with a positive RT-PCR result were enrolled in the treatment study. In the prevention study, the incidence of COVID-19 on Day 14 was similar between the ivermectin and the placebo group (4.7% vs. 5.2%; p = 0.844; Δ = −0.4%; 95% CI; −4.3−3.5%). In the treatment study, there was no significant difference between the ivermectin and placebo group for any Day 14 treatment outcome: proportion with oxygen desaturation (2.7% vs. 1.9%; p = 0.75), change in WHO score from baseline (1 [−5, 1] vs. 1 [−5, 1]; p = 0.50), and symptom resolution (76% vs. 82.2%; p = 0.13). The ivermectin group had a significantly higher proportion of transient blurred vision (5.6% vs. 0.6%; p < 0.001). Our study failed to demonstrate the efficacy of a 3-day once daily of ivermectin for the prevention and treatment of COVID-19. The given regimen of ivermectin should not be used for either prevention or treatment of COVID-19 in populations with a high rate of COVID-19 vaccination.

Early diagnosis by antigen test kit and early treatment by antiviral therapy: An ambulatory management strategy during COVID-19 crisis in Thailand.

This study aimed to assess the clinical characteristics of patients who registered at the Siriraj Favipiravir Clinic and to share our experiences in this comparatively unique clinical setting. This retrospective study included patients who registered at the Siriraj Favipiravir Clinic during August 11, 2021 to September 14, 2021. Included adult patients were those with severe acute respiratory syndrome coronavirus 2 (coronavirus disease 2019 [COVID-19]) infection confirmed by antigen test kit (ATK) or real-time reverse transcription-polymerase chain reaction, no favipiravir contraindication, no prior COVID-19 treatment, and not receiving care from another medical facility. Demographic data and outcomes were collected and analyzed. Of the 1168 patients (mean age: 44.8 ± 16.4 years, 55.7% female) who registered at the clinic, 117 (10%) did not meet the treatment criteria, and 141 (12%) patients did not pick up their medication. One-third of patients had at least 1 symptom that indicated severe disease. Higher proportion of unvaccinated status (56.7% vs 47.5%, P = .005), higher proportion of persons with risk factors for disease progression (37.7% vs 31.3%, P = .028), and longer duration between the date of clinic registration and the date of positive diagnostic test (3 vs 2 days, P = .004) were significantly more commonly observed in the severe disease group compared to the nonsevere disease group. The duration between symptom onset and the date of clinic registration was significantly longer in the real-time reverse transcription-polymerase chain reaction group than in the ATK group (6 vs 4 days, P < .001). Most patients (90.0%) had completed favipiravir treatment regimen. The improvement and mortality rates were 86.7% and 1.2%, respectively. COVID-19 severity is associated with vaccination status, baseline risk factors, and timing between disease detection and treatment. The use of ATK influences patients to seek treatment significantly earlier in ambulatory setting. Our early diagnosis and antiviral treatment strategy yielded favorable results in an outpatient setting during a COVID-19 outbreak in Thailand.

Early antiviral and supervisory dexamethasone treatment improve clinical outcomes of nonsevere COVID-19 patients.

This study aimed to evaluate the efficacy of early antiviral treatment in preventing clinical deterioration in asymptomatic or mildly symptomatic severe acute respiratory syndrome coronavirus 2 infected (COVID-19) patients in home isolation and to share our experiences with the ambulatory management of nonsevere COVID-19 patients. This retrospective study included mild COVID-19 adult patients confirmed by real-time reverse transcription-polymerase chain reaction. They received care via an ambulatory management strategy between July 2021 and November 2021. Demographic data, clinical progression, and outcomes were collected. Both descriptive and inferential statistics were performed to illustrate the cohort's characteristic and outcomes of the study. Univariable and multivariable logistic regression models were employed to investigate the associations between clinical factors and disease progression. A total of 1940 patients in the Siriraj home isolation system met the inclusion criteria. Their mean age was 42.1 ±â€…14.9 years, with 14.2% older than 60 years, 54.3% female, and 7.1% with a body weight ≥ 90 kg. Only 115 patients (5.9%) had deterioration of clinical symptoms. Two-thirds of these could be managed at home by dexamethasone treatment under physician supervision; however, 38 of the 115 patients (2.0% of the study cohort) needed hospitalization. Early favipiravir outpatient treatment (≤ 5 days from onset of symptoms) in nonsevere COVID-19 patients was significantly associated with a lower rate of symptom deterioration than late favipiravir treatment (50 [4.6%] vs 65 [7.5%] patients, respectively; P = .008; odds ratio 1.669; 95% confidence interval, 1.141-2.441). The unfavorable prognostic factors for symptom deterioration were advanced age, body weight ≥ 90 kg, unvaccinated status, higher reverse transcription-polymerase chain reaction cycle threshold, and late favipiravir treatment. The early delivery of essential treatment, including antiviral and supervisory dexamethasone, to ambulatory nonsevere COVID-19 patients yielded favorable outcomes during the COVID-19 pandemic in Thailand.

SARS-CoV-2 Antibody Response against Mild-to-Moderate Breakthrough COVID-19 in Home Isolation Setting in Thailand.

Background: In December 2021, Omicron replaced Delta as the dominant coronavirus disease 2019 (COVID-19) variant in Thailand. Both variants embody diverse epidemiological trends and immunogenicity. We investigated whether Delta and Omicron patients' biological and clinical characteristics and immunogenicity differed post-COVID-19 infection. Methods: This retrospective cohort study investigated the clinical outcomes and laboratory data of 5181 patients with mild-to-moderate COVID-19 (Delta, 2704; Omicron, 2477) under home isolation. We evaluated anti-receptor-binding domain immunoglobulin G (anti-RBD IgG) and surrogate viral neutralizing (sVNT) activity in 495 individuals post-COVID-19 infection during the Delta pandemic. Results: Approximately 84% of all patients received favipiravir. The median cycle threshold (Ct) values were lower for Omicron patients than Delta patients (19 vs. 21; p < 0.001), regardless of vaccination status. Upper respiratory tract symptoms were more frequent with Omicron patients than Delta patients. There were no significant associations between Ct and Omicron symptoms (95% confidence interval 0.98−1.02). A two-dose vaccine regimen reduced hospital readmission by 10% to 30% and death by under 1%. Anti-RBD IgG and sVNT against Delta were higher among older individuals post-COVID-19 infection. Older individuals expressed anti-RBD IgG and sVNT for a more extended period after two-dose vaccination than other age groups. Conclusions: After a full vaccination course, breakthrough mild-to-moderate Delta and Omicron infections have limited immunogenicity. Prior infections exert reduced protection against later reinfection or infection from novel variants. However, this protection may be sufficient to prevent hospitalization and death, particularly in countries where vaccine supplies are limited.