Cumulative incidence and mortality rate of cardiovascular complications due to laboratory-confirmed influenza virus infection: A systematic review and meta-analysis.

Influenza infection is associated with cardiovascular complications that range significantly in presentation and severity. The cumulative incidence of cardiovascular complications due to laboratory-confirmed influenza, however, is not reported in the literature. We conducted a systematic review and random-effects meta-analysis to evaluate the cumulative incidence and mortality rate of influenza virus-related cardiovascular complications in hospitalized patients. We searched the PubMed and EMBASE databases for studies reporting acute myocardial infarction (AMI), heart failure (HF), arrhythmia of any kind, stroke or transient ischemic attack (TIA), and myocarditis in hospitalized patients with laboratory-confirmed influenza virus infection. Prospective studies, retrospective cohort studies, and randomized controlled trials (RCTs) were included in the analysis. We followed the PRISMA checklist and used 95% confidence intervals (CIs) to report meta-analysis outcomes. This study was registered on PROSPERO (CRD42023427849). After retrieving 2803 studies, we identified 19 studies (18 observational and 1 RCT) with relevant data, and we included 6936 patients in our analysis, of whom 690 (9.9%) developed a cardiovascular outcome of interest. The cumulative incidence of HF was 17.47% (95% CI: 5.06%-34.54%), arrhythmia of any kind 6.12% (95% CI: 0.00%-21.92%), myocarditis 2.56% (95% CI: 0.66%-5.38%), AMI 2.19% (95% CI: 1.03%-3.72%), and stroke or TIA 1.14% (95% CI: 0.00%-4.05%). The in-hospital mortality rate from cardiovascular events was 1.38% (95% CI: 0.00%-4.80%). Cardiovascular complications occur in patients with influenza virus infection, with the cumulative incidence of specific cardiac manifestations varying considerably (1.51%-17.47%). Preventive strategies and close clinical monitoring after infection remain a priority.

In Enterobacterales bacteremia, antipseudomonal ß-lactam de-escalation was noninferior to continuation for clinical cure at 3 to 5 d.

SOURCE CITATION: López-Cortés LE, Delgado-Valverde M, Moreno-Mellado E, et al; SIMPLIFY study group. Efficacy and safety of a structured de-escalation from antipseudomonal ß-lactams in bloodstream infections due to Enterobacterales (SIMPLIFY): an open-label, multicentre, randomised trial. Lancet Infect Dis. 2024;24:375-385. 38215770.

In adults with post-COVID-19 conditions, a synbiotic preparation, SIM01, alleviated some symptoms at 6 mo.

SOURCE CITATION: Lau RI, Su Q, Lau IS, et al. A synbiotic preparation (SIM01) for post-acute COVID-19 syndrome in Hong Kong (RECOVERY): a randomised, double-blind, placebo-controlled trial. Lancet Infect Dis. 2024;24:256-265. 38071990.

Effect of Neutralizing Monoclonal Antibody Treatment on Early Trajectories of Virologic and Immunologic Biomarkers in Patients Hospitalized With COVID-19.

BACKGROUND: Neutralizing monoclonal antibodies (nmAbs) failed to show clear benefit for hospitalized patients with coronavirus disease 2019 (COVID-19). Dynamics of virologic and immunologic biomarkers remain poorly understood. METHODS: Participants enrolled in the Therapeutics for Inpatients with COVID-19 trials were randomized to nmAb versus placebo. Longitudinal differences between treatment and placebo groups in levels of plasma nucleocapsid antigen (N-Ag), anti-nucleocapsid antibody, C-reactive protein, interleukin-6, and D-dimer at enrollment, day 1, 3, and 5 were estimated using linear mixed models. A 7-point pulmonary ordinal scale assessed at day 5 was compared using proportional odds models. RESULTS: Analysis included 2149 participants enrolled between August 2020 and September 2021. Treatment resulted in 20% lower levels of plasma N-Ag compared with placebo (95% confidence interval, 12%-27%; P < .001), and a steeper rate of decline through the first 5 days (P < .001). The treatment difference did not vary between subgroups, and no difference was observed in trajectories of other biomarkers or the day 5 pulmonary ordinal scale. CONCLUSIONS: Our study suggests that nmAb has an antiviral effect assessed by plasma N-Ag among hospitalized patients with COVID-19, with no blunting of the endogenous anti-nucleocapsid antibody response. No effect on systemic inflammation or day 5 clinical status was observed. CLINICAL TRIALS REGISTRATION: NCT04501978.

A new class of synthetic retinoid antibiotics effective against bacterial persisters.

A challenge in the treatment of Staphylococcus aureus infections is the high prevalence of methicillin-resistant S. aureus (MRSA) strains and the formation of non-growing, dormant 'persister' subpopulations that exhibit high levels of tolerance to antibiotics and have a role in chronic or recurrent infections. As conventional antibiotics are not effective in the treatment of infections caused by such bacteria, novel antibacterial therapeutics are urgently required. Here we used a Caenorhabditis elegans-MRSA infection screen to identify two synthetic retinoids, CD437 and CD1530, which kill both growing and persister MRSA cells by disrupting lipid bilayers. CD437 and CD1530 exhibit high killing rates, synergism with gentamicin, and a low probability of resistance selection. All-atom molecular dynamics simulations demonstrated that the ability of retinoids to penetrate and embed in lipid bilayers correlates with their bactericidal ability. An analogue of CD437 was found to retain anti-persister activity and show an improved cytotoxicity profile. Both CD437 and this analogue, alone or in combination with gentamicin, exhibit considerable efficacy in a mouse model of chronic MRSA infection. With further development and optimization, synthetic retinoids have the potential to become a new class of antimicrobials for the treatment of Gram-positive bacterial infections that are currently difficult to cure.

Prevalence of Steatotic Liver Disease Among US Adults with Rheumatoid Arthritis.

BACKGROUND: The prevalence of steatotic liver disease (SLD) among patients with rheumatoid arthritis (RA) remains largely unknown. AIMS: To investigate the prevalence of SLD and liver fibrosis among patients with RA. METHODS: We utilized data from the United States (US)-based National Health and Nutrition Examination Survey (NHANES) 2017-2020 cycle. After applying established sample weights, we estimated the age-adjusted prevalence of SLD and its subclassifications (CAP ≥ 285 dB/m), high-risk NASH (FAST score) and liver fibrosis (LSM) among participants with self-reported RA. Multivariable logistic regression was performed to identify independent risk factors for metabolic dysfunction associated SLD (MASLD), high-risk NASH and fibrosis, respectively, among participants with RA. We present adjusted odds ratios (aORs) and 95% confidence intervals (CIs). RESULTS: Age-adjusted prevalence of MASLD among US adults with RA was 34.91% (95% CI: 24.02-47.65%). We also found that the age-adjusted prevalence of high-risk NASH (FAST score > 0.35) and significant fibrosis (LSM > 8.6 kPa) was 12.97% (95% CI: 6.89-23.07%) and 10.35% (95% CI: 5.55-18.48%), respectively. BMI ≥ 30 kg/m2, (aOR 6.23; 95% CI: 1.95-19.88), diabetes (aOR 5.90; 95% CI: 1.94-17.94), and dyslipidemia (aOR 2.83; 95% CI: 1.12-7.11) were independently associated with higher odds of MASLD among participants with RA. Diabetes (aOR 19.34; 95% CI: 4.69-79.70) was also independently associated with high-risk NASH. CONCLUSIONS: The prevalence of MASLD, high-risk NASH, and liver fibrosis among patients with RA is equal or higher than the general population. Future studies of large cohorts are needed to substantiate the role of systemic inflammation in the pathophysiology of MASLD.

In older adults, an AS01E-adjuvanted RSVPreF3 OA vaccine reduced RSV-related lower respiratory tract disease.

SOURCE CITATION: Papi A, Ison MG, Langley JM, et al; AReSVi-006 Study Group. Respiratory syncytial virus prefusion F protein vaccine in older adults. N Engl J Med. 2023;388:595-608. 36791160.

In older adults, an Ad26.RSV.preF-RSV preF protein vaccine reduced RSV-related lower respiratory tract disease.

SOURCE CITATION: Falsey AR, Williams K, Gymnopoulou E, et al; CYPRESS Investigators. Efficacy and safety of an Ad26.RSV.preF-RSV preF protein vaccine in older adults. N Engl J Med. 2023;388:609-620. 36791161.

A Pilot Trial of Thymalfasin (Thymosin-α-1) to Treat Hospitalized Patients With Hypoxemia and Lymphocytopenia Due to Coronavirus Disease 2019 Infection.

BACKGROUND: Thymosin-α-1 (Tα1) may be a treatment option for coronavirus disease 2019 (COVID-19), but efficacy and safety data remain limited. METHODS: Prospective, open-label, randomized trial assessing preliminary efficacy and safety of thymalfasin (synthetic form of Tα1), compared with the standard of care, among hospitalized patients with hypoxemia and lymphocytopenia due to COVID-19. RESULTS: A total of 49 patients were included in this analysis. Compared with control patients, the incidence of clinical recovery was higher for treated patients with either baseline low-flow oxygen (subdistribution hazard ratio, 1.48 [95% confidence interval, .68-3.25]) or baseline high-flow oxygen (1.28 [.35-4.63]), although neither difference was significant. Among patients with baseline low-flow oxygen, treated patients, compared with control patients, had an average difference of 3.84 times more CD4+ T cells on day 5 than on day 1 (P = .01). Nine serious adverse events among treated patients were deemed not related to Tα1. CONCLUSIONS: Tα1 increases CD4+ T-cell count among patients with baseline low-flow oxygen support faster than the standard of care and may have a role in the management of hospitalized patients with hypoxemia and lymphocytopenia due to COVID-19. CLINICAL TRIALS REGISTRATION: NCT04487444.

The Protective Role of Interleukin 17A in Acinetobacter baumannii Pneumonia Is Associated with Candida albicans in the Airway.

Recent studies have found that the coexistence of fungi and bacteria in the airway may increase the risk of infection, contribute to the development of pneumonia, and increase the severity of disease. Interleukin 17A (IL-17A) plays important roles in host resistance to bacterial and fungal infections. The objective of this study was to determine the effects of IL-17A on Acinetobacter baumannii-infected rats with a previous Candida albicans airway inoculation. The incidence of A. baumannii pneumonia was higher in rats with C. albicans in the airway than in noninoculated rats, and it decreased when amphotericin B was used to clear C. albicans, which influenced IL-17A levels. IL-17A had a protective effect in A. baumannii pneumonia associated with C. albicans in the airway. Compared with A. baumannii-infected rats with C. albicans in the airway that did not receive IL-17A, recombinant IL-17A (rIL-17A) supplementation decreased the incidence of A. baumannii pneumonia (10/15 versus 5/17; P = 0.013) and the proportion of neutrophils in the lung (84 ± 3.5 versus 74 ± 4.3%; P = 0.033), reduced tissue destruction and inflammation, and decreased levels of myeloperoxidase (MPO) (1.267 ± 0.15 versus 0.233 ± 0.06 U/g; P = 0.0004), reactive oxygen species (ROS) (132,333 ± 7,505 versus 64,667 ± 10,115 AU; P = 0.0007) and lactate dehydrogenase (LDH) (2.736 ± 0.05 versus 2.1816 ± 0.29 U/g; P = 0.0313). In vitro experiments revealed that IL-17A had no significant effect on the direct migration ability and bactericidal capability of neutrophils. However, IL-17A restrained lysis cell death and increased apoptosis of neutrophils (2.9 ± 1.14 versus 7 ± 0.5%; P = 0.0048). Taken together, our results suggest that C. albicans can depress IL-17A levels, which when supplemented may have a regulatory function that limits the accumulation of neutrophils in inflammatory areas, providing inflammatory response homeostasis.

Biological Evaluation of the Antibacterial Retinoid CD437 in Cutibacterium acnes Infection.

Acne vulgaris is a complex skin disease involving infection by Cutibacterium acnes, inflammation, and hyperkeratinization. We evaluated the activity of the retinoid 6-[3-(adamantyl)-4-hydroxyphenyl]-2-naphthalene carboxylic acid (CD437) and 16 other retinoid analogs as potential anti-C. acnes compounds and found that CD437 displayed the highest antimicrobial activity with an MIC against C. acnes (ATCC 6919 and HM-513) of 1 µg/mL. CD437 demonstrated an MBC of 2 µg/mL compared to up to 64 µg/mL for the retinoid adapalene and up to 16 µg/mL for tetracycline, which are commonly used clinically to treat acne. Membrane permeability assays demonstrated that exposure of C. acnes ATCC 6919 to CD437 damaged the integrity of C. acnes ATCC 6919 bacterial membranes, and this finding was confirmed with scanning electron microscopy. Additionally, CD437 downregulated the expression of C. acnes ATCC 6919 virulence factors, including the genes encoding Christie-Atkins-Munch-Petersen factor 1 (CAMP1), CAMP2, glycerol-ester hydrolase B (GehB), sialidase B, and neuraminidase. In a mouse skin infection model of C. acnes ATCC 6919, topical treatment with CD437 ameliorated skin lesions and reduced the bacterial burden in situ (P < 0.001). In human NHEK primary cells, CD437 reduced the transcriptional levels of the coding genes for inflammatory cytokines (interleukin-1α, ~10-fold; interleukin-6, ~20-fold; interleukin-8, ~30-fold; and tumor necrosis factor-alpha, ~6-fold) and downregulated the transcriptional levels of KRT10 (~10-fold), FLG (~4-fold), and TGM1 (~2-fold), indicating that CD437 can diminish inflammation and hyperkeratinization. In summary, CD437 deserves further attention for its dual function as a potential acne therapeutic that potentially acts on both the pathogen and the host.

Prevalence of Steatotic Liver Disease (MASLD, MetALD, and ALD) in the United States: NHANES 2017-2020.

Following the Delphi consensus process, the term steatotic liver disease (SLD) was introduced to replace fatty liver disease, while the term metabolic dysfunction-associated steatotic liver disease (MASLD) emerged as the successor to the term nonalcoholic fatty liver disease (NAFLD).1 This revised nomenclature aims to enhance precision and mitigate negative connotations and potential stigmatization, while refining comprehension and disease categorization. Concurrently, a novel category was introduced to capture individuals whose alcohol consumption exceeded the previously defined thresholds of NAFLD but remained unclassified within the existing system. This category, termed MetALD, now delineates a spectrum of conditions and is defined as a daily intake of 20 to 50 g of alcohol (or weekly 140-350 g) for females and 30 to 60 g daily for males (or weekly 210-420 g).1 Within the MetALD spectrum, some individuals might predominantly exhibit MASLD characteristics, whereas others might be more inclined toward alcoholic liver disease (ALD).1 In the present study, we used a US nationally representative data set to calculate the prevalence of SLD and its subcategories in the United States.

Prevalence and Characteristics of Nonalcoholic Fatty Liver Disease and Fibrosis in People Living With HIV Monoinfection: A Systematic Review and Meta-analysis.

BACKGROUND AND AIMS: Liver disease remains a leading cause of morbidity and mortality among people living with HIV (PLWH). Emerging data suggest that PLWH are at high risk for developing nonalcoholic fatty liver disease (NAFLD). The aim of this review is to examine the current literature and provide an accurate estimate of the prevalence of NAFLD, nonalcoholic steatohepatitis (NASH), and fibrosis, and identify potential risk factors for NAFLD in PLWH. METHODS: We searched PubMed and Embase databases to identify studies reporting the prevalence of NAFLD and/or fibrosis in PLWH monoinfection. We performed a random effects meta-analysis of proportions to estimate the pooled prevalence of NAFLD, NASH, and fibrosis among PLWH monoinfection. We also examined potential risk factors for NAFLD by comparing characteristics of PLWH monoinfection with and without NAFLD. RESULTS: A total of 43 studies, reporting data for 8230 patients, met our eligibility criteria and were included in the meta-analysis. Based on imaging studies the overall pooled prevalence of NAFLD and moderate liver fibrosis (METAVIR ≥ F2) among PLWH monoinfection was 33.9% (95% confidence interval [CI], 29.67%-38.39%), and 12.00% (95% CI, 10.02%-14.12%), respectively. Based on biopsy studies, prevalence of NASH and significant liver fibrosis (stage ≥F2 on histology) was 48.77% (95% CI, 34.30%-63.34%) and 23.34% (95% CI, 14.98%-32.75%), respectively. Traditional metabolic syndrome and HIV-related factors were associated with NAFLD in PLWH. CONCLUSIONS: Our study confirms that the burden of NAFLD, NASH, and fibrosis is high among PLWH monoinfection. Prospective longitudinal studies are needed to delineate NAFLD, NASH, and fibrosis risk factors, and identify early interventions and new therapies for NAFLD in this population.

Impact of prior HBV, HAV, and HEV infection on non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) is a leading cause of chronic liver disease. The association between prior hepatitis B virus (HBV), hepatitis A virus (HAV), hepatitis E virus (HEV) infection and NAFLD remains unclear. We utilized the 2017-2020 National Health and Nutrition Examination Survey (NHANES) and performed multivariable logistic regression analyses to examine the association of prior HBV, HAV and HEV infection with NAFLD, as well as high risk non-alcoholic steatohepatitis (NASH) and liver fibrosis. Our analysis included 2565 participants with available anti-HBc serology results, 1480 unvaccinated participants with anti-HAV results, and 2561 participants with anti-HEV results. Among participants with NAFLD, the age-adjusted prevalence of prior HBV, HAV and HEV infection was 3.48%, 32.08% and 7.45%, respectively. Prior infection with HBV, HAV and HEV was not associated with NAFLD (cut-off 285 dB/m) [aOR: 0.99 (95% CI, 0.77-1.29), 1.29 (95% CI, 0.95-1.75), and 0.94 (95% CI, 0.70-1.27), respectively] or high-risk NASH [aOR 0.72 (95% CI, 0.45-1.17), 0.92 (95% CI, 0.55-1.52), and 0.89 (95% CI, 0.41-1.94), respectively]. Participants with anti-HBc and anti-HAV seropositivity were more likely to have significant fibrosis [aOR: 1.53 (95% CI, 1.05-2.23) and 1.69 (95% CI, 1.16-2.47), respectively]. The odds of significant fibrosis are 53%, and 69% greater for participants with prior history of HBV and HAV infection. Healthcare providers should prioritize vaccination efforts and employ a tailored approach to NAFLD in patients with prior viral hepatitis and especially HBV or HAV infection to limit disease-related outcomes.

SARS-CoV-2 Antibody Responses to the Ancestral SARS-CoV-2 Strain and Omicron BA.1 and BA.4/BA.5 Variants in Nursing Home Residents After Receipt of Bivalent COVID-19 Vaccine - Ohio and Rhode Island, September-November 2022.

Introduction of monovalent COVID-19 mRNA vaccines in late 2020 helped to mitigate disproportionate COVID-19-related morbidity and mortality in U.S. nursing homes (1); however, reduced effectiveness of monovalent vaccines during the period of Omicron variant predominance led to recommendations for booster doses with bivalent COVID-19 mRNA vaccines that include an Omicron BA.4/BA.5 spike protein component to broaden immune response and improve vaccine effectiveness against circulating Omicron variants (2). Recent studies suggest that bivalent booster doses provide substantial additional protection against SARS-CoV-2 infection and severe COVID-19-associated disease among immunocompetent adults who previously received only monovalent vaccines (3).* The immunologic response after receipt of bivalent boosters among nursing home residents, who often mount poor immunologic responses to vaccines, remains unknown. Serial testing of anti-spike protein antibody binding and neutralizing antibody titers in serum collected from 233 long-stay nursing home residents from the time of their primary vaccination series and including any subsequent booster doses, including the bivalent vaccine, was performed. The bivalent COVID-19 mRNA vaccine substantially increased anti-spike and neutralizing antibody titers against Omicron sublineages, including BA.1 and BA.4/BA.5, irrespective of previous SARS-CoV-2 infection or previous receipt of 1 or 2 booster doses. These data, in combination with evidence of low uptake of bivalent booster vaccination among residents and staff members in nursing homes (4), support the recommendation that nursing home residents and staff members receive a bivalent COVID-19 booster dose to reduce associated morbidity and mortality (2).

80% of patients with COVID-19 have ≥1 long-term effect at 14 to 110 d after initial symptoms.

SOURCE CITATION: Lopez-Leon S, Wegman-Ostrosky T, Perelman C, et al. More than 50 long-term effects of COVID-19: a systematic review and meta-analysis. Sci Rep. 2021;11:16144. 34373540.

In patients with COVID-19 at risk for severe disease, nirmatrelvir + ritonavir reduced hospitalization or death.

SOURCE CITATION: Hammond J, Leister-Tebbe H, Gardner A, et al. Oral nirmatrelvir for high-risk, nonhospitalized adults with Covid-19. N Engl J Med. 2022;386:1397-408. 35172054.

In inpatients with COVID-19 who need supplemental oxygen, lenzilumab increased ventilation-free survival.

SOURCE CITATION: Temesgen Z, Burger CD, Baker J, et al. Lenzilumab in hospitalised patients with COVID-19 pneumonia (LIVE-AIR): a phase 3, randomised, placebo-controlled trial. Lancet Respir Med. 2022;10:237-46. 34863332.

Efficacy and Safety of Ensovibep for Adults Hospitalized With COVID-19 : A Randomized Controlled Trial.

BACKGROUND: Ensovibep (MP0420) is a designed ankyrin repeat protein, a novel class of engineered proteins, under investigation as a treatment of SARS-CoV-2 infection. OBJECTIVE: To investigate if ensovibep, in addition to remdesivir and other standard care, improves clinical outcomes among patients hospitalized with COVID-19 compared with standard care alone. DESIGN: Double-blind, randomized, placebo-controlled, clinical trial. (ClinicalTrials.gov: NCT04501978). SETTING: Multinational, multicenter trial. PARTICIPANTS: Adults hospitalized with COVID-19. INTERVENTION: Intravenous ensovibep, 600 mg, or placebo. MEASUREMENTS: Ensovibep was assessed for early futility on the basis of pulmonary ordinal scores at day 5. The primary outcome was time to sustained recovery through day 90, defined as 14 consecutive days at home or place of usual residence after hospital discharge. A composite safety outcome that included death, serious adverse events, end-organ disease, and serious infections was assessed through day 90. RESULTS: An independent data and safety monitoring board recommended that enrollment be halted for early futility after 485 patients were randomly assigned and received an infusion of ensovibep (n = 247) or placebo (n = 238). The odds ratio (OR) for a more favorable pulmonary outcome in the ensovibep (vs. placebo) group at day 5 was 0.93 (95% CI, 0.67 to 1.30; P = 0.68; OR > 1 would favor ensovibep). The 90-day cumulative incidence of sustained recovery was 82% for ensovibep and 80% for placebo (subhazard ratio [sHR], 1.06 [CI, 0.88 to 1.28]; sHR > 1 would favor ensovibep). The primary composite safety outcome at day 90 occurred in 78 ensovibep participants (32%) and 70 placebo participants (29%) (HR, 1.07 [CI, 0.77 to 1.47]; HR < 1 would favor ensovibep). LIMITATION: The trial was prematurely stopped because of futility, limiting power for the primary outcome. CONCLUSION: Compared with placebo, ensovibep did not improve clinical outcomes for hospitalized participants with COVID-19 receiving standard care, including remdesivir; no safety concerns were identified. PRIMARY FUNDING SOURCE: National Institutes of Health.

The Association of Baseline Plasma SARS-CoV-2 Nucleocapsid Antigen Level and Outcomes in Patients Hospitalized With COVID-19.

BACKGROUND: Levels of plasma SARS-CoV-2 nucleocapsid (N) antigen may be an important biomarker in patients with COVID-19 and enhance our understanding of the pathogenesis of COVID-19. OBJECTIVE: To evaluate whether levels of plasma antigen can predict short-term clinical outcomes and identify clinical and viral factors associated with plasma antigen levels in hospitalized patients with SARS-CoV-2. DESIGN: Cross-sectional study of baseline plasma antigen level from 2540 participants enrolled in the TICO (Therapeutics for Inpatients With COVID-19) platform trial from August 2020 to November 2021, with additional data on day 5 outcome and time to discharge. SETTING: 114 centers in 10 countries. PARTICIPANTS: Adults hospitalized for acute SARS-CoV-2 infection with 12 days or less of symptoms. MEASUREMENTS: Baseline plasma viral N antigen level was measured at a central laboratory. Delta variant status was determined from baseline nasal swabs using reverse transcriptase polymerase chain reaction. Associations between baseline patient characteristics and viral factors and baseline plasma antigen levels were assessed using both unadjusted and multivariable modeling. Association between elevated baseline antigen level of 1000 ng/L or greater and outcomes, including worsening of ordinal pulmonary scale at day 5 and time to hospital discharge, were evaluated using logistic regression and Fine-Gray regression models, respectively. RESULTS: Plasma antigen was below the level of quantification in 5% of participants at enrollment, and 1000 ng/L or greater in 57%. Baseline pulmonary severity of illness was strongly associated with plasma antigen level, with mean plasma antigen level 3.10-fold higher among those requiring noninvasive ventilation or high-flow nasal cannula compared with room air (95% CI, 2.22 to 4.34). Plasma antigen level was higher in those who lacked antispike antibodies (6.42 fold; CI, 5.37 to 7.66) and in those with the Delta variant (1.73 fold; CI, 1.41 to 2.13). Additional factors associated with higher baseline antigen level included male sex, shorter time since hospital admission, decreased days of remdesivir, and renal impairment. In contrast, race, ethnicity, body mass index, and immunocompromising conditions were not associated with plasma antigen levels. Plasma antigen level of 1000 ng/L or greater was associated with a markedly higher odds of worsened pulmonary status at day 5 (odds ratio, 5.06 [CI, 3.41 to 7.50]) and longer time to hospital discharge (median, 7 vs. 4 days; subhazard ratio, 0.51 [CI, 0.45 to 0.57]), with subhazard ratios similar across all levels of baseline pulmonary severity. LIMITATIONS: Plasma samples were drawn at enrollment, not hospital presentation. No point-of-care test to measure plasma antigen is currently available. CONCLUSION: Elevated plasma antigen is highly associated with both severity of pulmonary illness and clinically important patient outcomes. Multiple clinical and viral factors are associated with plasma antigen level at presentation. These data support a potential role of ongoing viral replication in the pathogenesis of SARS-CoV-2 in hospitalized patients. PRIMARY FUNDING SOURCE: U.S. government Operation Warp Speed and National Institute of Allergy and Infectious Diseases.