Automatic Detection of Lung Ultrasound Artifacts using a Deep Neural Networks approach

The COVID-19 pandemic has challenged many of the healthcare systems around the world. Many patients who have been hospitalized due to this disease develop lung damage. In low and middle-income countries, people living in rural and remote areas have very limited access to adequate health care. Ultrasound is a safe, portable and accessible alternative;however, it has limitations such as being operator-dependent and requiring a trained professional. The use of lung ultrasound volume sweep imaging is a potential solution for this lack of physicians. In order to support this protocol, image processing together with machine learning is a potential methodology for an automatic lung damage screening system. In this paper we present an automatic detection of lung ultrasound artifacts using a Deep Neural Network, identifying clinical relevant artifacts such as pleural and A-lines contained in the ultrasound examination taken as part of the clinical screening in patients with suspected lung damage. The model achieved encouraging preliminary results such as sensitivity of 94%, specificity of 81%, and accuracy of 89% to identify the presence of A-lines. Finally, the present study could result in an alternative solution for an operator-independent lung damage screening in rural areas, leading to the integration of AI-based technology as a complementary tool for healthcare professionals. © 2023 SPIE.

Development of an acquisition system to monitoring asynchronous tele-ultrasound for lung patients

Lung ultrasound imaging allows the detection and evaluation of the lung damage generated by COVID-19. However, several infrastructure and logistical limitations prevent them from being carried out in isolated and remote areas. In this work, a system for the acquisition of medical images through asynchronous tele-ultrasounds was developed. The system is based on a graphical user interface, which records the three video cameras, the ultrasound image and the accelerometer simultaneously. The interface was developed according to the Volume Sweep Imaging acquisition protocol. The translational and rotational movement of the transducer are tracked and monitored by the accelerometer and the position of the transducer is obtained from the images acquired by the three video cameras. The results show a correct functioning of the system overall, being viable to be implemented for data acquisition and calculation of error, although in order to validate the error calculation there is still more research to be done. © 2023 SPIE.

Academic Analytics Applied in the Study of the Relationship Between the Initial Profile of Undergraduate Students and Early Drop-Out Rates. Defining the Variables of a Predictor Instrument

The field of university dropout research is of utmost importance especially in the current context arising from the Covid-19 pandemic. Students who started their degrees in the last two years completed their pre-university studies during various phases of confinement and by combining traditional and virtual training. In this scenario, students' motivation and the way they cope with the difficulties of their first year of university are very relevant and will depend on a multitude of personal and social variables in their immediate environment. Previous studies have shown that many university students drop out of their studies early, but what factors and to what extent they affect this dropout is still a field under study. This paper focuses on the identification, classification and evaluation of a set of indicators based on teacher and tutor perception in different fields of study by applying quantitative and qualitative techniques. The results of pilot studies developed support the approach adopted, as they show how teachers can identify students at risk of dropping out at the beginning of the course and take proactive measures to monitor and motivate them, thus reducing the possibility of dropout. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

Experiences of psychosocial coping in the context of compulsory social isolation, in family heads of Metropolitan Lima

This research seeks to analyze the experiences of psychosocial coping in the context of Obligatory Social Isolation, brough about by COVID-19, in heads of families of Metropolitan Lima, Peru. In order to do this, we developed a qualitative research with a phenomenological design;semi-structured interviews were carried out with 17 participants, heads of their families, from districts with high and low income. The results show that, on the one hand, participants experience styles focused on the problem, which encompass active coping, planning, restructuring their activities and routines, as well as displacement and change of priorities. On the other hand, we have the styles centered on emotions, such as acceptance and agency, search for emotional support, positive reinterpretation and the release of emotions. Likewise, there are differences in the ways in which people cope, both regarding their belonging to districts with higher or lower income, or in relation to whether they are men, women or non-binary people. We conclude that the coping experiences vary according to the different socioeconomic and gender characteristics of the participants, requiring an intersectional perspective in the analysis. © 2022 Universidad de Alicante. All rights reserved.

Natalizumab, a valuable strategy for immunisation to avoid delays of treatment onset in highly active MS patients

Background: Vaccination during immunosuppression can result in impaired vaccine responses. In highly active patients requiring a rapid treatment initiation, vaccination can delay treatment onset. Natalizumab (NTZ) is a high-efficacy agent with potential low interference in vaccination responses, and could be a bridge therapy to achieve an adequate immunisation before starting another treatment. Objective(s): To assess the safety and immunogenicity of inactivated vaccines administered during NTZ treatment. Method(s): Self-controlled study based on an ongoing prospective cohort that included adult MS patients with complete immunisation schedules for hepatitis B vaccine (HBV), hepatitis A vaccine (HAV) and/or COVID-19 vaccine during NTZ treatment, between September 2016 and February 2022. Seroprotection rates were calculated for each vaccine. Demographic, clinical and radiological characteristics were collected the year before (pre-exposure period) and after vaccination (post-exposure period). Differences in annual relapse rate (ARR), contrast-enhancing lesions (CELs), new T2 lesions (NewT2) and changes in Expanded Disability Status Scale (EDSS) during pre and post exposure period were evaluated. Patients were also categorised according to time on NTZ exposure before vaccination (long-term exposure >1 year and short-exposure <=1 year) and according to JCV status. Result(s): From 248 patients treated with NTZ, 60 were vaccinated during NTZ exposure: 44 (73%) women, mean age 45 years, mean disease duration 17 (SD 8.7) years. Thirty (50%) patients bridged to anti-CD20 after immunisation, because of high titers of JC virus. Between the pre and post-exposure period, we observed a decrease in both the AAR (0.28 vs 0.01;p=0.004) and newT2 (0.8 vs 0.02;p=0.1) and no changes in disability accumulation (EDSS 3.5 vs 3.5 p=0.6). The global seroprotection rate was 93% (91.6% (IC95% 73-99) for HAV (n=24), 92.6% (IC95% 76- 99) for HBV (n=27), 100% (IC95% 84-100) for Covid-19 (n=23)). No differences were seen between short and long term NTZ exposure or between JCV positive or negative patients, in terms of safety and immunogenicity. Conclusion(s): Immunisation with inactivated vaccines during NTZ treatment is safe and effective, both for short and long term NTZ exposure. In highly active PwMS who need immunisation, NTZ could be a valuable strategy to avoid delays in the onset of high-efficacy DMD, even in JC virus positive in which it could be used as a bridge therapy strategy.

Rural rates of hepatitis C within an emergency department-based universal screening program

Study Objective: As a consequence of the opioid epidemic, overall Hepatitis C (HCV) infections have increased in the United States. HCV mortality now surpasses more than 60 other infections (eg, HIV, and TB). The CDC now recommends universal HCV screening, for all adults aged =18 years. Several reports highlight the success of large urban EDs to provide screening and linkage to care for HCV but the ability to utilize rural EDs has not been explored. Our objective was to highlight results of an electronic health record (EHR) driven "opt-out," universal HCV screening program in a small rural community ED that serves the economically disadvantaged, rural/mountainous area of SC, including parts of Appalachia.

An overview of COVID-19 related to fungal infections: what do we know after the first year of pandemic?

In 2019, severe acute respiratory syndrome caused by CoV-2 virus became a pandemic worldwide, being the fast spread of the disease due to the movement of infected people from one country to another, from one continent to another, or within the same country. Associated comorbidities are important factors that predispose to any fungal coinfections. Because of the importance of fungal infections in COVID-19 patients, the aim of this work was to collect data of the more encountered mycoses related to patients undergoing this disease. Aspergillosis was the first COVID-19-related fungal infection reported, being A. fumigatus the most frequent species for CAPA. Other fungal infections related include mainly candidiasis and mucormycosis, being Rhizopus spp. the more prevalent species found. Influenza-associated pulmonary aspergillosis is well documented; thus, similar complications are expected in severe forms of COVID-19 pneumonia. Therefore, in patients with COVID-19, it is important to take special attention to the surveillance and suspicion of fungal coinfections that might worsen the patient's prognosis.

Humoral and cellular responses to SARS-CoV-2 in convalescent COVID-19 patients with multiple sclerosis

Introduction: Information about how SARS-CoV-2 specific humoral and cellular response is modified by disease-modifying therapies (DMTs) is scarce. Objective: To investigate humoral and cellular responses to SARS-CoV-2 and factors for presenting them in a Barcelona cohort of pwMS. Methods: Retrospective cohort study of adult unvaccinated PwMS with confirmed COVID-19 with at least one SARS-CoV-2 antibody (Ab) determination included from February 2020 to May 2021 and followed until May 2021. Demographic, clinical and laboratory data were obtained. Humoral SARS-CoV-2 response was measured with commercial chemiluminescence immunoassays targeting specific Ab against spike (IgG-S) and nucleocapsid proteins (Ig-N), as per clinical practice. SARS-CoV-2 specific T-cell response was studied in 42 selected pwMS according to DMT by a whole blood Interferon-Gamma (IFN-y) Release Immunoassay. Humoral and cellular response was assesed using a logistic regression model corrected for age, sex, comorbidities, MS form, expanded disability status scale, DMT, COVID-19 severity and PCR result. Results: 145 pwMS were enrolled (mean age 46.8 years;64.1% female;18.6% progressive forms, 20.7% untreated, 22.8% on anti-CD20s therapies and 56.6% on other DMTs). Humoral and cellular tests were performed from 0.3 to 13.1 months after COVID-19. 121(83.5%) presented positive Ab (57.6% anti-CD20 therapy, 90.2% other DMTs, 93.3% untreated). Untreated patients presented higher Ig-N titres (34.3[128.8]) compared to those with anti-CD20s (0.08[0.13], p<0.01), and other DMTs (19.55[42.92], p<0.01). Humoral response persisted over 6 months in 12/12 untreated, 9/22 with anti-CD20s and 22/28 with other DMTs (p=0.068). 31/42(73.8%) presented cellular response (81.0% anti- CD20, 62.5% other DMTs, 80.0% untreated), with similar levels of IFN-y levels among DMTs. 5/12(41.7%) anti-CD20-treated PwMS with negative Ab presented cellular response. In the multivariate analysis, humoral response decreased in anti-CD20 therapy (OR 0.08[95% CI,0.01-0.55]) and was associated with male sex (OR 3.59[1.02-12.68]). Cellular response was associated with seropositivity (OR13.0[1.29-130.4]), but can be present even in the absence of Ab. Conclusions: Humoral response is altered by DMTs, specially in anti-CD20-treated PwMS. Cellular response is associated with seropositivity but can be present in anti-CD20-treated PwMS even in the absence of Ab. Both can be detected up to 13.1 months after COVID-19.

Humoral and cellular responses to SARS-CoV-2 vaccination in patients with multiple sclerosis and other autoimmune diseases

Background: Information about humoral and cellular responses to SARS-CoV-2 vaccination in patients with Multiple Sclerosis (PwMS) and other autoimmune diseases (AID) is scarce. Objective: To determine humoral and cellular responses after SARS-CoV-2 vaccination in PwMS and anti-CD20-treated patients with other AID. Methods: Ongoing prospective study performed in two Catalan MS centres from February 2021. Unvaccinated adult pwMS and other anti-CD20-treated AID were recruited. Demographic, clinical and laboratory data were obtained. Whole blood samples were obtained before and 30-90 days after vaccination. The humoral response to SARS-CoV-2 was qualitatively and quantitatively measured before and after vaccination with commercial chemiluminescence immunoassays targeting SARS-CoV-2 antibodies against spike (TrimericS, IgG anti-S) and nucleocasid proteins (Elecsys, Ig anti-N). In 150 selected patients according to diseasemodifying therapy (DMT), the SARS-CoV-2 specific T-cell response was assessed after vaccination by a whole blood Interferon-Gamma Release immuno Assay (IGRA) that uses two Qiagen proprietary mixes of SARS-CoV-2 S protein (Ag.1 and Ag.2) selected to activate both CD4 and CD8 T cells. Results: 457 patients have been enrolled in the study (anti-CD20 therapy n=164, S1P DMTs n=37, natalizumab n=32, cladribine n=29, alemtuzumab n=31, other DMTs n=129, no DMT n=35). Participants characteristics are: mean age 48.1 years (SD 12.0), 69% female, 422 pwMS (29.4% progressive forms) and 35 with other AID, disease duration 13.9 years (IQR 14.1), median EDSS 3.0 (IQR 3.0). 450 have been fully vaccinated (94.2% mRNA vaccine). Pre-vaccination samples were collected 0.33 days (SD 0.5) before the first vaccine dose of which 12 (3.35%) had positive anti S/N immunoglobulin (Ig). As of June 30th, 42 post-vaccination samples have been obtained (1.3 months [SD 0.42] after the 2nd vaccination dose). Positive IgG rates were 44.8% (n=13/29) for CD20s, 100% (8/8) for other DMTs and 100% (4/4) for no DMT. No anti-N Ig were detected. Media titres of anti-S IgG were lower in anti-CD20-treated patients (7.8 [IQR 50.1]) compared to untreated patients (800 [0], p<0.01) or other DMTs (755 [228], p<0.01). Conclusions: Initial results of the study suggest blunted anti-S/N Ig response under anti-CD20 therapy. Knowledge of the cellular response in these patients will be crucial. Data from the cellular study and the completed humoral study will be presented at the meeting.

Infection Risk in Lymphoproliferative Diseases (LPD) Treated with Targeted Drugs. Geltamo Real-Life Experience

Introduction:Recently there has been a renewal of therapeutic tools for the treatment of lymphoid neoplasms to increase the antitumor efficacy and reduce the toxicity generated by conventional chemotherapies, which adds to the intrinsic immunological dysfunction of the disease itself. To date, few data are published about infection risk of these new drugs, and the need for infectious prophylaxis is unknown. The aim of the study is to analyze the infectious complications in patients with LPD treated with monoclonal antibodies (obinutuzumab, ofatumumab, brentuximab, nivolumab and pembrolizumab), BTK inhibitors (ibrutinib, acalabrutinib) and PI3K inhibitors (idelalisib). Methods: Multicenter retrospective study in patients with LPD treated with targeted therapies (single agents or combination) in 18 Hematology centers in Spain, from the time of their commercial availability to March 2020. Patients in clinical trials were excluded as well as patients with active infections at the beginning of treatment. Results:During the study period, 380 patients were included.Baseline characteristics of the entire cohort are shown in Table 1.Median follow-up was 17.3 months (range 0-103), the longest follow-up corresponding to CLL patients (24 months, range 0-98) and the shortest to LBCL (5 months, range 0-25). Median exposure to target drugs was 8 months (range 0-72).Ibrutinib was administered to 219 patients(1 FL, 147 CLL, 27 MCL, 10 DLBCL, 1 TL and 32 WM, 1 HL),Brentuximab to 49(31 HL, 14 TL and 4 DLBCL) andIdelalisibto 35 patients (16 affected by chronic lymphocytic leukemia - CLL, 15 FL and 1 DLBCL, 1 WM, 1MCL, 1HL).Obinutuzumabcombinations were used in 10 (6 CLL, 3 FL, 1 MCL) and 5 HL patients (of which 4/5 underwent previous BMT) receivedNivolumab. A total number of 237 infectious events occurred in 148/380 patients (38.9%), 39% of which were grade 3 and 54/148 (36.4%) experienced 2 or more infective episodes: of those 54, 21 (38%) had underwent 3 or more lines of therapy and 28 (51%) had hypogammaglobulinemia. Hospitalization was required in 59.2% events. A bacterial cause of infection was reported in 40% of cases, and viral in 16%, including 11/237 (4,6%) SARS-CoV-2 infection. Invasive fungal infection (IFI) occurred in 3.3% (8/237). Noteworthy, no case of PJP was identified. Lung was the most frequent site of infection in 24% of cases (57/237) while the upper respiratory tract was involved in 17% of events (41/237). Urinary tract infections were diagnosed in 10% (24/237). Other sites involved were skin and soft tissue 7%, gastrointestinal tract 5,4%, bloodstream infections 3% and catheter related infections 2,5%. Considering drugs individually, 86 patients that receivedIbrutinib(39.2 %)experienced a total of 137 infectious episodes: 30% bacterial, 19% viral, 5% fungal and 45% clinical and image-based infections;the 17(34.6%of those who received Brentuximab, experienced a total of 16 infectious episodes: 56% bacterial, 37.5% viral infections and one catheter-related sepsis. Of those who receivedIdelalisib,18 (51.4%)experienced a total of 28 episodes: 42% bacterial, 14% viral and 7% fungal. Four patients treated withObinutuzumabcombinations (40%) experienced one infection during treatment (25% bacterial and 75% viral). Only one patient treated withNivolumabexperienced more than three infections, he was also under corticosteroid treatment. Focusing on IFI (Table 2): 7/8 infections were identified in CLL patients, 6 out 7 being on ibrutinib treatment and 1/7 on Idelalisib.Aspergilluswas the fungus most frequently isolated. The targeted drug was discontinued temporarily in 4 patients and indefinitely in 3. Twenty three (6%) patients died due to infection in our series. Conclusions: 1. We identified 38.7% infections in our LPD patients treated with targeted drugs, with a median drug-exposure time of 8 months (range 0-72), with a non-negligible incidence of bacterial infections. 2. The highest rates of infection were found in patients treated with with Idelalisib and Ibrutinib (51.4% and 39.2% respectively). 3. IFI (3.3%) occurr d with low frequency, mostly in CLL patients during ibrutinib treatment, leading to its temporal discontinuation in most of the cases. 4. No case of PJP was identified in our cohort. 5. An analysis to determine risk factors for infection and the optimal monitoring and prophylaxis for these patients is ongoing. [Formula presented] Disclosures: Hernandez-Rivas:Janssen:Membership on an entity's Board of Directors or advisory committees;Abbvie:Membership on an entity's Board of Directors or advisory committees;Roche:Membership on an entity's Board of Directors or advisory committees;AstraZeneca:Membership on an entity's Board of Directors or advisory committees;Gilead:Membership on an entity's Board of Directors or advisory committees;Celgene/BMS:Membership on an entity's Board of Directors or advisory committees;Rovi:Membership on an entity's Board of Directors or advisory committees.Lopez-Guillermo:novartis:Consultancy;celgene:Consultancy, Research Funding;roche:Consultancy, Research Funding;gilead:Consultancy, Research Funding.

Symptoms and Pulmonary Function Improvement after 4 Months of Acute COVID 19 in a Mexican Population

Rationale: Pulmonary function abnormalities have been known to last for months or even years in recovered survivors from previous coronavirus pneumonias. However, the long-term pulmonary sequelae of coronavirus disease 2019 (COVID-19) is unknown, and comprehensive clinical follow-up data are lacking, particularly in low-medium income countries. Accordingly, the purpose of this study was to describe changes in persistent symptoms and pulmonary function abnormalities at approximately two and four months of follow-up. Methods: We conducted a prospective, observational study in patients recovering from COVID-19. Patients were evaluated in the pulmonary function laboratory at approximately two and fourth months following the onset of COVID-19 symptoms. During the follow-up visits, patients were asked to report all persistent symptoms at the time of testing from a list currently recognized as part of post COVID syndrome. They then underwent a standardized 6-Minute Walk Test (6MWT) and pulmonary function testing, which included spirometry and diffusion capacity for carbon monoxide (DLCO). Patients were excluded if they were unable to complete all pulmonary function tests in the two follow-up visits. Wilcoxon signed-rank test and McNemar's test were used where appropriate to compare anthropometric, pulmonary function, symptoms, and 6MWT variables between follow-up visits. Results: A total of 30 COVID-19 confirmed patients were included for the follow-up evaluation. The median time from the onset of COVID-19 symptoms to follow-up was 54 days (IQR: 47-70 days) for the first visit and 120 days (IQR: 111-135 days) for the second visit. Although symptoms persisted at the second follow-up visit, the majority of persistent symptoms improved compared to the first visit (Table 1). There was also a marked improvement in the median number of symptoms at the second compared to the first follow-up visit (2 vs. 4 symptoms, respectively, p=0.003). There was a significant improvement in forced vital capacity, forced expiratory volume in 1 second, DLCO, and the proportion of patients with a persistent restrictive pattern on spirometry (Table 1). Despite improvements in pulmonary function, there was no significant change in 6-minute walk distance, although there was a significant improvement in end exercise SpO2. Conclusions: A significant proportion of patients in this study showed improvements in persistent symptoms and pulmonary function at 120 days compared to 54 days following the onset of acute COVID-19 symptoms. Characterizing changes in pulmonary function, symptoms, and functional capacity over time will enable clinicians to understand the long-term implications and recovery trajectory of their COVID-19 patients.

Pulmonary Function and Functional Capacity in COVID19 Survivors with and Without Persistent Dyspnea in a Mexican Population

Rationale: Dyspnea is one of the most common symptoms associated with coronavirus disease 2019 (COVID-19). Over 40% of COVID-19 survivors experience persistent dyspnea approximately 60 days following hospital discharge (Carfi et al., JAMA, 2020). Understanding differences in pulmonary function and functional capacity between those that do and do not experience persistent dyspnea may provide insight into the underlying mechanisms of this symptom in survivors of COVID-19. Accordingly, the purpose of this study was to compare spirometry, diffusing capacity of the lungs for carbon monoxide (DLCO), and 6-minute walk test (6MWT) outcomes in COVID-19 patients with and without persistent dyspnea. We hypothesized that COVID-19 patients with persistent dyspnea would have lower forced vital capacity (FVC), DLCO, and 6-minute walk distance (6MWD) compared to patients without persistent dyspnea. Methods: Non-critical patients (n=186) with varying degrees of COVID-19 severity reported all persistent symptoms using a standardized questionnaire and underwent pulmonary function testing and a 6MWT between 30 and 90 days following the onset of acute COVID-19 symptoms. Patients were divided into those with (n=70) and those without (n=116) persistent dyspnea. Independent t-tests and Fisher's Exact test were used where appropriate to compare anthropometric, pulmonary function, symptoms, and 6MWT variables. Results: There was no difference in the time of experimental testing relative to the onset of acute COVID-19 symptoms between those with vs. those without dyspnea (59±13 vs. 60±14 days, respectively). Groups had similar age, height, mass, body mass index, sex, and frequency of comorbidities. Patients with persistent dyspnea had significantly lower FVC (p=0.03), forced expiratory volume in 1 second (p=0.04), and DLCO (p=0.01) compared to non-dyspnea patients. 47% of patients with persistent dyspnea had a restrictive pattern on spirometry compared to 33% in the non-dyspnea group. Patients with persistent dyspnea also had lower 6MWD (% predicted, p=0.03) and nadir oxygen saturation (p<0.001), and higher Borg 0-10 ratings of dyspnea and fatigue (both p<0.001) during the 6MWT compared to patients without persistent dyspnea. Conclusions: We have shown that dyspnea is a common persistent symptom across varying degrees of initial COVID-19 severity. Patients with persistent dyspnea had a number of abnormalities compared to well-matched patients without persistent dyspnea, including greater restriction on spirometry, lower DLCO, reduced functional capacity, and increased desaturation and exertional symptoms during a 6MWT. This suggests that there is a true physiological mechanism that may explain persistent dyspnea after COVID-19.

Predictors of functional outcome after COVID-19 illness: A prospective study in mexico

Rationale: Clinical outcomes after coronavirus-2019 disease (COVID-19) have been well described, including persistent symptoms and abnormalities on pulmonary function tests and imaging. However, the presence and underlying mechanism of functional impairments after COVID-19 remain unclear. Methods: Patients with SARS-CoV-2 confirmed by real-time polymerase chain reaction were recruited from a hospital in Yucatan, Mexico. Patients who were able to complete surveys, pulmonary function tests, and 6-minute walk tests within 30-90 days after symptom onset were included. COVID-19 severity based on the location of treatment and need for supplemental oxygen was categorized as follows: mild (ambulatory, no hypoxemia), moderate (ambulatory, supplemental oxygen (O2) ≤ 5 l/min), or severe (hospitalised, O2 > 5 l/min without invasive mechanical ventilation). The association between COVID-19 severity and 6-minute walk distance (6MWD) was determined using multivariable linear regression, and underlying mechanisms for reduced 6MWD were then explored. Unadjusted and adjusted linear regression models were used to determine the association between potential predictor variables (Borg dyspnea, Borg fatigue, and end-exercise SpO2) and 6MWD. A final model with Borg dyspnea and end-exercise SpO2 as co-primary endpoints was performed to explore the independent relationship of these two predictors with 6MWD. All models were adjusted for age, sex, smoking, and body mass index (BMI). Results: There were 148 eligible patients with a mean age of 47±14 years and BMI of 32±7kg/m2, with 66% males and 19% current or past-smokers. There were 26% patients with mild, 10% with moderate, and 64% with severe COVID-19 illness. The mean follow-up time was 59 days. The mean 6MWD was 450±104m (83±19% predicted). Patients with severe COVID-19 had a lower 6MWD compared to patients with mild COVID-19 (- 52m [95%CI -88,-15], p=0.006). There was no difference in 6MWD between mild and moderate COVID-19. For every unit increase, Borg dyspnea (coefficient -21m [95%CI -31,-10]) and end-exercise SpO2 (coefficient 13m [95%CI 8,18]) were associated with 6MWD (both p<0.001);however, Borg fatigue was not. When Borg dyspnea and end-exercise SpO2 were included as co-primary predictors, both variables remained independently associated with reduced 6MWD with coefficients of -13m (95%CI -23,-2) and 10m (95%CI 5,16), respectively, after adjusting for covariates (Table 1). Conclusions: Patients with severe COVID-19 had significantly lower 6MWD compared to those with mild disease. Exertional dyspnea and hypoxemia were independent predictors of lower 6MWD, suggesting that dyspnea related to hypoxemia is not the sole driver of reduced functional capacity in COVID- 19 survivors.