A prospective natural history study of post acute sequalae of COVID-19 using digital wearables: Study protocol (preprint)

Background Post-acute sequelae of COVID-19 (PASC) is characterized by having 1 + persistent, recurrent, or emergent symptoms post the infection’s acute phase. The duration and symptom manifestation of PASC remain understudied in nonhospitalized patients. Literature on PASC is primarily based on data from hospitalized patients where clinical indicators such as respiratory rate, heart rate, and oxygen saturation have been predictive of disease trajectories. Digital wearables allow for a continuous collection of such physiological parameters. This protocol outlines the design, aim, and procedures of a natural history study of PASC using digital wearables.Methods This is a single-arm, prospective, natural history study of a cohort of 550 patients, ages 18 to 65 years old, males or females who own a smartphone and/or a tablet that meets pre-determined Bluetooth version and operating system requirements, speak English, and provide documentation of a positive COVID-19 test issued by a healthcare professional or organization within 5 days before enrollment. The study aims to identify wearables collected physiological parameters that are associated with PASC in patients with a positive diagnosis. The primary endpoint is long COVID-19, defined as ≥ 1 symptom at 3 weeks beyond first symptom onset or positive diagnosis, whichever comes first. The secondary endpoint is chronic COVID-19, defined as ≥ 1 symptom at 12 weeks beyond first symptom onset or positive diagnosis. We hypothesize that physiological parameters collected via wearables are associated with self-reported PASC. Participants must be willing and able to consent to participate in the study and adhere to study procedures for six months.Discussion This is a fully decentralized study investigating PASC using wearable devices to collect physiological parameters and patient-reported outcomes. Given evidence on key demographics and risk profiles associated with PASC, the study will shed light on the duration and symptom manifestation of PASC in nonhospitalized patient subgroups and is an exemplar of use of wearables as population-level monitoring health tools for communicable diseases.Trial registration: ClinicalTrials.gov NCT04927442, Submitted: 6/15/2021, First posted: 6/16/2021.

Effectiveness of the Coronavirus Disease 2019 Bivalent Vaccine.

Background: The purpose of this study was to evaluate whether a bivalent coronavirus disease 2019 (COVID-19) vaccine protects against COVID-19. Methods: The study included employees of Cleveland Clinic in employment when the bivalent COVID-19 vaccine first became available. Cumulative incidence of COVID-19 over the following 26 weeks was examined. Protection provided by vaccination (analyzed as a time-dependent covariate) was evaluated using Cox proportional hazards regression, with change in dominant circulating lineages over time accounted for by time-dependent coefficients. The analysis was adjusted for the pandemic phase when the last prior COVID-19 episode occurred and the number of prior vaccine doses. Results: Among 51 017 employees, COVID-19 occurred in 4424 (8.7%) during the study. In multivariable analysis, the bivalent-vaccinated state was associated with lower risk of COVID-19 during the BA.4/5-dominant (hazard ratio, 0.71 [95% confidence interval, .63-79]) and the BQ-dominant (0.80 [.69-.94]) phases, but decreased risk was not found during the XBB-dominant phase (0.96 [.82-.1.12]). The estimated vaccine effectiveness was 29% (95% confidence interval, 21%-37%), 20% (6%-31%), and 4% (-12% to 18%), during the BA.4/5-, BQ-, and XBB-dominant phases, respectively. The risk of COVID-19 also increased with time since the most recent prior COVID-19 episode and with the number of vaccine doses previously received. Conclusions: The bivalent COVID-19 vaccine given to working-aged adults afforded modest protection overall against COVID-19 while the BA.4/5 lineages were the dominant circulating strains, afforded less protection when the BQ lineages were dominant, and effectiveness was not demonstrated when the XBB lineages were dominant.

EEG Findings in Coronavirus Disease.

PURPOSE: Neurologic manifestations of coronavirus disease (COVID-19) such as encephalopathy and seizures have been described. To our knowledge, detailed EEG findings in COVID-19 have not yet been reported. This report adds to the scarce body of evidence. METHODS: We identified eight COVID-19 positive patients who underwent EEG monitoring in our hospital system. RESULTS: EEGs were most commonly ordered for an altered level of consciousness, a nonspecific neurologic manifestation. We observed generalized background slowing in all patients and generalized epileptiform discharges with triphasic morphology in three patients. Focal electrographic seizures were observed in one patient with a history of focal epilepsy and in another patient with no such history. Five of eight patients had a previous diagnosis of epilepsy, suggesting that pre-existing epilepsy can be a potential risk factor for COVID-19-associated neurological manifestations. Five of eight patients who underwent EEG experienced a fatal outcome of infection. CONCLUSIONS: Our findings underscore previous observations that neurologic manifestations are common in severe cases. COVID-19 patients with epilepsy may have an increased risk of neurological manifestations and abnormal EEG.

Thinking Outside the Box: Advancing Clinical Education in an Era of Preceptor Shortage.

ABSTRACT: The expansion of health professions educational programs has led to an acute shortage of available clinical training sites. Rapid growth in the number of medical schools, physician assistant (PA) programs, and advanced nurse practitioner (APRN) programs, all of which share a need for similar types of clinical training experiences, has increased competition for clinical training sites and placed new challenges on educational institutions. Solutions are urgently needed to increase the quantity and quality of supervised clinical practice experiences as well as to ensure diversity among preceptors and geographical clinical sites. This article identifies key barriers to securing sufficient clinical training sites, notes emerging trends, and presents potential innovations through stakeholder collaboration for enhancing clinical training across health professions.

Outcome trajectories in a county mental health clinic before and after telemental health: a retrospective COVID-19 cohort study.

Background/objectives: Telemental health (TMH) care has received increased attention, most recently due to the COVID-19 pandemic. Many treatment settings and clinicians were forced to rapidly shift to TMH modalities, including clinicians with limited exposure to and possibly negative attitudes toward alternative treatment delivery formats. With the shift to new modalities, effectiveness research is necessary to understand if patients are receiving the same quality of care as before the pandemic and their receipt of mostly in person services. This study compared the naturalistic treatment outcome trajectories for a cohort of patients who received in-person services prior to the pandemic and a distinct cohort of patients who received TMH services after the onset of the pandemic, in a community mental health setting with limited exposure to TMH prior to the COVID-19 pandemic. Materials and methods: We adopted a retrospective cohort design to examine treatment modality as a between-group moderator of symptom change trajectory on the self-report Patient Health Questionnaire (PHQ-9) in a sample of N = 958 patients in the Northeast United States. Treatment durations differed in the naturalistic treatment setting and we examined patient-reported outcomes up to a maximum of one year. Results: Statistically significant average decreases in symptom severity were found over the course of up to one year of treatment, yet the average outcome trajectory was not significantly different between two modality cohorts (in person delivery before the pandemic versus TMH delivery after pandemic onset). Conclusion: These findings suggest that even in a setting with limited exposure to or training in TMH, the average outcome trajectory for patients who received TMH was statistically similar to the outcome trajectory for patients in an earlier cohort who received in-person services prior to the pandemic onset. Overall, the results appear to support continued use of TMH services in community treatment settings.

Effect of P2Y12 Inhibitors on Organ Support-Free Survival in Critically Ill Patients Hospitalized for COVID-19: A Randomized Clinical Trial.

Importance: Platelet activation is a potential therapeutic target in patients with COVID-19. Objective: To evaluate the effect of P2Y12 inhibition among critically ill patients hospitalized for COVID-19. Design, Setting, and Participants: This international, open-label, adaptive platform, 1:1 randomized clinical trial included critically ill (requiring intensive care-level support) patients hospitalized with COVID-19. Patients were enrolled between February 26, 2021, through June 22, 2022. Enrollment was discontinued on June 22, 2022, by the trial leadership in coordination with the study sponsor given a marked slowing of the enrollment rate of critically ill patients. Intervention: Participants were randomly assigned to receive a P2Y12 inhibitor or no P2Y12 inhibitor (usual care) for 14 days or until hospital discharge, whichever was sooner. Ticagrelor was the preferred P2Y12 inhibitor. Main Outcomes and Measures: The primary outcome was organ support-free days, evaluated on an ordinal scale that combined in-hospital death and, for participants who survived to hospital discharge, the number of days free of cardiovascular or respiratory organ support up to day 21 of the index hospitalization. The primary safety outcome was major bleeding, as defined by the International Society on Thrombosis and Hemostasis. Results: At the time of trial termination, 949 participants (median [IQR] age, 56 [46-65] years; 603 male [63.5%]) had been randomly assigned, 479 to the P2Y12 inhibitor group and 470 to usual care. In the P2Y12 inhibitor group, ticagrelor was used in 372 participants (78.8%) and clopidogrel in 100 participants (21.2%). The estimated adjusted odds ratio (AOR) for the effect of P2Y12 inhibitor on organ support-free days was 1.07 (95% credible interval, 0.85-1.33). The posterior probability of superiority (defined as an OR > 1.0) was 72.9%. Overall, 354 participants (74.5%) in the P2Y12 inhibitor group and 339 participants (72.4%) in the usual care group survived to hospital discharge (median AOR, 1.15; 95% credible interval, 0.84-1.55; posterior probability of superiority, 80.8%). Major bleeding occurred in 13 participants (2.7%) in the P2Y12 inhibitor group and 13 (2.8%) in the usual care group. The estimated mortality rate at 90 days for the P2Y12 inhibitor group was 25.5% and for the usual care group was 27.0% (adjusted hazard ratio, 0.96; 95% CI, 0.76-1.23; P = .77). Conclusions and Relevance: In this randomized clinical trial of critically ill participants hospitalized for COVID-19, treatment with a P2Y12 inhibitor did not improve the number of days alive and free of cardiovascular or respiratory organ support. The use of the P2Y12 inhibitor did not increase major bleeding compared with usual care. These data do not support routine use of a P2Y12 inhibitor in critically ill patients hospitalized for COVID-19. Trial Registration: ClinicalTrials.gov Identifier: NCT04505774.

GWAS and meta-analysis identifies 49 genetic variants underlying critical COVID-19.

Critical illness in COVID-19 is an extreme and clinically homogeneous disease phenotype that we have previously shown1 to be highly efficient for discovery of genetic associations2. Despite the advanced stage of illness at presentation, we have shown that host genetics in patients who are critically ill with COVID-19 can identify immunomodulatory therapies with strong beneficial effects in this group3. Here we analyse 24,202 cases of COVID-19 with critical illness comprising a combination of microarray genotype and whole-genome sequencing data from cases of critical illness in the international GenOMICC (11,440 cases) study, combined with other studies recruiting hospitalized patients with a strong focus on severe and critical disease: ISARIC4C (676 cases) and the SCOURGE consortium (5,934 cases). To put these results in the context of existing work, we conduct a meta-analysis of the new GenOMICC genome-wide association study (GWAS) results with previously published data. We find 49 genome-wide significant associations, of which 16 have not been reported previously. To investigate the therapeutic implications of these findings, we infer the structural consequences of protein-coding variants, and combine our GWAS results with gene expression data using a monocyte transcriptome-wide association study (TWAS) model, as well as gene and protein expression using Mendelian randomization. We identify potentially druggable targets in multiple systems, including inflammatory signalling (JAK1), monocyte-macrophage activation and endothelial permeability (PDE4A), immunometabolism (SLC2A5 and AK5), and host factors required for viral entry and replication (TMPRSS2 and RAB2A).

COVID-19 and Religious Ethics.

The editors of the JRE solicited short essays on the COVID-19 pandemic from a group of scholars of religious ethics that reflected on how the field might help them make sense of the complex religious, cultural, ethical, and political implications of the pandemic, and on how the pandemic might shape the future of religious ethics.

Prognostic performance of blood neurofilament light chain protein in hospitalized COVID-19 patients without major central nervous system manifestations: an individual participant data meta-analysis.

BACKGROUND AND AIMS: To investigate the prognostic value of blood neurofilament light chain protein (NfL) levels in the acute phase of coronavirus disease 2019 (COVID-19). METHODS: We conducted an individual participant data (IPD) meta-analysis after screening on MEDLINE and Scopus to May 23rd 2022. We included studies with hospitalized adult COVID-19 patients without major COVID-19-associated central nervous system (CNS) manifestations and with a measurement of blood NfL in the acute phase as well as data regarding at least one clinical outcome including intensive care unit (ICU) admission, need of mechanical ventilation (MV) and death. We derived the age-adjusted measures NfL Z scores and conducted mixed-effects modelling to test associations between NfL Z scores and other variables, encompassing clinical outcomes. Summary receiver operating characteristic curves (SROCs) were used to calculate the area under the curve (AUC) for blood NfL. RESULTS: We identified 382 records, of which 7 studies were included with a total of 669 hospitalized COVID-19 cases (mean age 66.2 ± 15.0 years, 68.1% males). Median NfL Z score at admission was elevated compared to the age-corrected reference population (2.37, IQR: 1.13-3.06, referring to 99th percentile in healthy controls). NfL Z scores were significantly associated with disease duration and severity. Higher NfL Z scores were associated with a higher likelihood of ICU admission, need of MV, and death. SROCs revealed AUCs of 0.74, 0.80 and 0.71 for mortality, need of MV and ICU admission, respectively. CONCLUSIONS: Blood NfL levels were elevated in the acute phase of COVID-19 patients without major CNS manifestations and associated with clinical severity and poor outcome. The marker might ameliorate the performance of prognostic multivariable algorithms in COVID-19.

Mendelian randomization of genetically independent aging phenotypes identifies LPA and VCAM1 as biological targets for human aging.

Length and quality of life are important to us all, yet identification of promising drug targets for human aging using genetics has had limited success. In the present study, we combine six European-ancestry genome-wide association studies of human aging traits-healthspan, father and mother lifespan, exceptional longevity, frailty index and self-rated health-in a principal component framework that maximizes their shared genetic architecture. The first principal component (aging-GIP1) captures both length of life and indices of mental and physical wellbeing. We identify 27 genomic regions associated with aging-GIP1, and provide additional, independent evidence for an effect on human aging for loci near HTT and MAML3 using a study of Finnish and Japanese survival. Using proteome-wide, two-sample, Mendelian randomization and colocalization, we provide robust evidence for a detrimental effect of blood levels of apolipoprotein(a) and vascular cell adhesion molecule 1 on aging-GIP1. Together, our results demonstrate that combining multiple aging traits using genetic principal components enhances the power to detect biological targets for human aging.

Why Do We Need Food Systems Informatics? Introduction to This Special Collection on Smart and Connected Regional Food Systems

Public interest in where food comes from and how it is produced, processed, and distributed has increased over the last few decades, with even greater focus emerging during the COVID-19 pandemic. Mounting evidence and experience point to disturbing weaknesses in our food systems' abilities to support human livelihoods and wellbeing, and alarming long-term trends regarding both the environmental footprint of food systems and mounting vulnerabilities to shocks and stressors. How can we tackle the "wicked problems” embedded in a food system? More specifically, how can convergent research programs be designed and resulting knowledge implemented to increase inclusion, sustainability, and resilience within these complex systems, support widespread contributions to and acceptance of solutions to these challenges, and provide concrete benchmarks to measure progress and understand tradeoffs among strategies along multiple dimensions? This article introduces and defines food systems informatics (FSI) as a tool to enhance equity, sustainability, and resilience of food systems through collaborative, user-driven interaction, negotiation, experimentation, and innovation within food systems. Specific benefits we foresee in further development of FSI platforms include the creation of capacity-enabling verifiable claims of sustainability, food safety, and human health benefits relevant to particular locations and products;the creation of better incentives for the adoption of more sustainable land use practices and for the creation of more diverse agro-ecosystems;the wide-spread use of improved and verifiable metrics of sustainability, resilience, and health benefits;and improved human health through better diets.

The Relationship between Exercise Volume and Disease Severity among Patients Who Tested Positive for COVID-19

[...]the relationship between exercise volume during a pandemic and COVID-19 disease severity was examined to inform the nursing community and others who educate patients on a healthy lifestyle. Researchers have concluded exercise may play an important role in countering respiratory symptoms associated with COViD-19 (Mohamed & Alawna, 2020). [...]the current authors sought to determine if exercise volume was related to symptoms and hospitalization from COVID-19. Use of four exercise volume groups would provide 80% power to detect correlations in excess of 0.16 with outcome measures, and effect size differences of 0.5 or higher based on a sample of 400 respondents. Comorbidities and risk factors were obtained from the COVID-19 registry, including smoking, chronic obstructive pulmonary disease (COPD), asthma, diabetes, hypertension, coronary artery disease, heart failure, cancer (type), transplant, multiple sclerosis, connective tissue disease, inflammatory bowel disease, HIV, other immunosuppressive disease, other heart disease, other lung disease, pregnancy, and epilepsy.

COVID-19 vaccination telephone outreach: an analysis of the medical student experience.

INTRODUCTION: The COVID-19 pandemic diminished opportunities for medical students to gain clinical confidence and the ability to contribute to patient care. Our study sought out to understand the value of telephone outreach to schedule COVID-19 vaccines on medical student education. MATERIALS AND METHODS: Forty students engaged in telephone outreach targeting patients aged 65+ without active patient portals to schedule COVID-19 vaccines. Data consisted of a single administration retrospective pre/post survey inquiring about what students learned, expectations, other health-care processes that would benefit from outreach, and interest in a population health elective. Likert items were analyzed and open response analysis involved inductive coding and generation of thematic summaries by condensing codes into broader themes. Demographic data of patients called and subsequently received the vaccine were also collected. RESULTS: There were 33 survery respondents. There was a statistically significant increase in net comfortability for pre-clerkship students for documenting in Epic, providing telehealth care, counseling on common health-care myths, having challenging conversations, cold-calling patients, and developing an initial trusting relationship with patients. The majority called and who received the vaccine were non-Hispanic Black, within the high SVI category, and had Medicare and/or Medicaid. Qualitative data showed that students emphasized communication, the role of trusted messengers, the need to be open minded, and meeting patients where they are. DISCUSSION: Engaging students in telephone outreach early in the COVID-19 pandemic provided students the opportunity to develop their skills as physicians-in-training, contribute to combating the ongoing pandemic, and add value to the primary care team. This experience allowed students to practice patience, empathy, and vulnerability to understand why patients had not received the COVID-19 vaccine; this was an invaluable experience that helped students develop the skills to become empathetic and caring physicians, and supports the continued role of telehealth in future medical school curriculum.

The Isolation and In Vitro Differentiation of Primary Fetal Baboon Tracheal Epithelial Cells for the Study of SARS-CoV-2 Host-Virus Interactions.

The mucociliary airway epithelium lines the human airways and is the primary site of host-environmental interactions in the lung. Following virus infection, airway epithelial cells initiate an innate immune response to suppress virus replication. Therefore, defining the virus-host interactions of the mucociliary airway epithelium is critical for understanding the mechanisms that regulate virus infection, including Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Non-human primates (NHP) are closely related to humans and provide a model to study human disease. However, ethical considerations and high costs can restrict the use of in vivo NHP models. Therefore, there is a need to develop in vitro NHP models of human respiratory virus infection that would allow for rapidly characterizing virus tropism and the suitability of specific NHP species to model human infection. Using the olive baboon (Papio anubis), we have developed methodologies for the isolation, in vitro expansion, cryopreservation, and mucociliary differentiation of primary fetal baboon tracheal epithelial cells (FBTECs). Furthermore, we demonstrate that in vitro differentiated FBTECs are permissive to SARS-CoV-2 infection and produce a potent host innate-immune response. In summary, we have developed an in vitro NHP model that provides a platform for the study of SARS-CoV-2 infection and other human respiratory viruses.

Safety and efficacy of zilucoplan in patients with generalised myasthenia gravis (RAISE): a randomised, double-blind, placebo-controlled, phase 3 study.

BACKGROUND: Generalised myasthenia gravis is a chronic, unpredictable, and debilitating rare disease, often accompanied by high treatment burden and with an unmet need for more efficacious and well tolerated treatments. Zilucoplan is a subcutaneous, self-administered macrocyclic peptide complement C5 inhibitor. We aimed to assess safety, efficacy, and tolerability of zilucoplan in patients with acetylcholine receptor autoantibody (AChR)-positive generalised myasthenia gravis. METHODS: RAISE was a randomised, double-blind, placebo-controlled, phase 3 trial that was done at 75 sites in Europe, Japan, and North America. We enrolled patients (aged 18-74 years) with AChR-positive generalised myasthenia gravis (Myasthenia Gravis Foundation of America disease class II-IV), a myasthenia gravis activities of daily living (MG-ADL) score of least 6, and a quantitative myasthenia gravis score of at least 12. Participants were randomly assigned (1:1) to receive subcutaneous zilucoplan 0·3 mg/kg once daily by self-injection, or matched placebo, for 12 weeks. The primary efficacy endpoint was change from baseline to week 12 in MG-ADL score in the modified intention-to-treat population (all randomly assigned patients who received at least one dose of study drug and had at least one post-dosing MG-ADL score). Safety was mainly assessed by the incidence of treatment-emergent adverse events (TEAEs) in all patients who had received at least one dose of zilucoplan or placebo. This trial is registered at ClinicalTrials.gov, NCT04115293. An open-label extension study is ongoing (NCT04225871). FINDINGS: Between Sept 17, 2019, and Sept 10, 2021, 239 patients were screened for the study, of whom 174 (73%) were eligible. 86 (49%) patients were randomly assigned to zilucoplan 0·3 mg/kg and 88 (51%) were assigned to placebo. Patients assigned to zilucoplan showed a greater reduction in MG-ADL score from baseline to week 12, compared with those assigned to placebo (least squares mean change -4·39 [95% CI -5·28 to -3·50] vs -2·30 [-3·17 to -1·43]; least squares mean difference -2·09 [-3·24 to -0·95]; p=0·0004). TEAEs occurred in 66 (77%) patients in the zilucoplan group and in 62 (70%) patients in the placebo group. The most common TEAE was injection-site bruising (n=14 [16%] in the zilucoplan group and n=8 [9%] in the placebo group). Incidences of serious TEAEs and serious infections were similar in both groups. One patient died in each group; neither death (COVID-19 [zilucoplan] and cerebral haemorrhage [placebo]) was considered related to the study drug. INTERPRETATION: Zilucoplan treatment showed rapid and clinically meaningful improvements in myasthenia gravis-specific efficacy outcomes, had a favourable safety profile, and was well tolerated, with no major safety findings. Zilucoplan is a new potential treatment option for a broad population of patients with AChR-positive generalised myasthenia gravis. The long-term safety and efficacy of zilucoplan is being assessed in an ongoing open-label extension study. FUNDING: UCB Pharma.

How an Australian Centre for Disease Control Can Reinforce Environmental Health Systems and Services

The Australian government is working to establish a Center for Disease Control (CDC). The goal is to ensure pandemic preparedness, lead the federal response to future disease outbreaks, and prevent noncommunicable and communicable diseases. This news is welcomed as Australia is the only country in the Organization for Economic Co-operation and Development (OECD) without a CDC or similar national organization. The nation is uniquely placed to build on lessons from other countries to create a "world-class" Australian CDC by reinforcing environmental health systems and becoming the champion for evidence-based policy.

Associations of Physical Inactivity and COVID-19 Outcomes Among Subgroups.

INTRODUCTION: Physical activity before COVID-19 infection is associated with less severe outcomes. The study determined whether a dose‒response association was observed and whether the associations were consistent across demographic subgroups and chronic conditions. METHODS: A retrospective cohort study of Kaiser Permanente Southern California adult patients who had a positive COVID-19 diagnosis between January 1, 2020 and May 31, 2021 was created. The exposure was the median of at least 3 physical activity self-reports before diagnosis. Patients were categorized as follows: always inactive, all assessments at 10 minutes/week or less; mostly inactive, median of 0-60 minutes per week; some activity, median of 60-150 minutes per week; consistently active, median>150 minutes per week; and always active, all assessments>150 minutes per week. Outcomes were hospitalization, deterioration event, or death 90 days after a COVID-19 diagnosis. Data were analyzed in 2022. RESULTS: Of 194,191 adults with COVID-19 infection, 6.3% were hospitalized, 3.1% experienced a deterioration event, and 2.8% died within 90 days. Dose‒response effects were strong; for example, patients in the some activity category had higher odds of hospitalization (OR=1.43; 95% CI=1.26, 1.63), deterioration (OR=1.83; 95% CI=1.49, 2.25), and death (OR=1.92; 95% CI=1.48, 2.49) than those in the always active category. Results were generally consistent across sex, race and ethnicity, age, and BMI categories and for patients with cardiovascular disease or hypertension. CONCLUSIONS: There were protective associations of physical activity for adverse COVID-19 outcomes across demographic and clinical characteristics. Public health leaders should add physical activity to pandemic control strategies.

Leflunomide Confers Rapid Recovery from COVID-19 and is Coupled with Temporal Immunologic Changes.

Background: Vaccines for SARS-CoV-2 have been considerably effective in reducing rates of infection and severe COVID-19. However, many patients, especially those who are immunocompromised due to cancer or other factors, as well as individuals who are unable to receive vaccines or are in resource-poor countries, will continue to be at risk for COVID-19. We describe clinical, therapeutic, and immunologic correlatives in two patients with cancer and severe COVID-19 who were treated with leflunomide after failing to respond to standard-of-care comprising remdesivir and dexamethasone. Both patients had breast cancer and were on therapy for the malignancy. Methods: The protocol is designed with the primary objective to assess the safety and tolerability of leflunomide in treating severe COVID-19 in patients with cancer. Leflunomide dosing consisted of a loading dose of 100 mg daily for the first three days, followed by daily dosing, at the assigned dose level (Dose Level 1: 40 mg, Dose Level -1, 20 mg; Dose Level 2, 60 mg), for an additional 11 days. At defined intervals, serial monitoring of blood samples for toxicity, pharmacokinetics, and immunologic correlative studies were performed, as well as nasopharyngeal swabs for PCR analysis of SARS-CoV-2. Results: Preclinically, leflunomide impaired viral RNA replication, and clinically, it led to a rapid improvement in the two patients discussed herein. Both patients completely recovered, with minimal toxicities; all adverse events experienced were considered unrelated to leflunomide. Single-cell mass-cytometry analysis showed that leflunomide increased levels of CD8+ cytotoxic and terminal effector T cells and decreased naïve and memory B cells. Conclusions: With ongoing COVID-19 transmission and occurrence of breakthrough infections in vaccinated individuals, including patients with cancer, therapeutic agents that target both the virus and host inflammatory response would be helpful despite the availability of currently approved anti-viral agents. Furthermore, from an access to care perspective, especially in resource-limited areas, an inexpensive, readily available, effective drug with existing safety data in humans is relevant in the real-world setting.