Sars-CoV-2 Antibody Response Before and After Third Dose of Homologous mRNA Vaccine in Liver Transplant Recipients

Purpose: Liver transplant (LT) recipients have a decreased response to 2 doses of SARS-CoV-2 vaccine compared to the general population, so we aimed to understand response to a third dose to inform vaccination strategies. Method(s): LT recipients in our observational cohort who received 3 homologous mRNA vaccines and available antibody levels pre- and post-dose 3 (D3) were identified. Those who reported a prior COVID-19 diagnosis or used belatacept were excluded. The peak anti-spike antibody level collected between the second (D2) and third dose (D3), was compared to the antibody level at 1 month post-D3. Samples were tested with Roche Elecsys Anti-Sars-CoV-2 enzyme immunoassay (EIA) (positive >=0.8 U/mL) or EUROIMMUN EIA (positive >=1.1 AU). Result(s): 146 participants completed 3 homologous doses of BNT162b2 (53%) or mRNA-1273 (47%) vaccines between 5/15/2021 - 11/8/2021. The median (IQR) time of peak pre-D3 antibody collection was 89 (31, 104) days post-D2. The median time of 1-month post-D3 antibody collection was 30 (23, 33) days. The median time between D2 and D3 was 168 (149-188) days. Overall, 125/146 (86%) were seropositive pre-D3, and 139/146 (95%) were seropositive post-D3 (Figure 1). There were no seroreversions post D3, and among the 21 seronegative recipients pre-D3, 14 (67%) seroconverted post-D3. Risk factors significantly associated with persistent seronegativity post-D3 were less time since LT (1.3 vs 6 years, p=0.042), mycophenolate use (100% vs 37%, p=0.001), BNT162b2 series (100% vs 50%, p=0.01), and pre-D3 seronegative status (86% vs 10%, p<0.001). Conclusion(s): Most LT recipients have excellent responses to a third homologous mRNA vaccine dose, greater than that seen in other transplant recipients. Persons seronegative after D2, however, show weaker response and may remain at high risk for SARS-CoV-2 infection despite D3.

Antibody Response to 3-Dose SARS-CoV-2 mRNA Vaccination in Pediatric Solid Organ Transplant Recipients

Purpose: We report the immunogenicity and safety of a third BNT162b2 vaccine in pediatric solid organ transplant recipients (pSOTRs). Method(s): Samples from pSOTRs (12-18 years) enrolled in our multicenter, observational study (COVID-19 Antibody Testing of Recipients of Solid Organ Transplants and Patients with Chronic Diseases) who received a third vaccine (V3) were analyzed for antibodies to SARS-CoV-2 spike protein receptor-binding domain, with a positive cutoff of >=0.8 and maximum titer of >2500 U/mL. Pre-V3 samples were 1-3 months after vaccine 2, and post-V3 were 1 month after vaccine 3. Result(s): Thirty-seven pSOTRs (46% heart, 24% liver, 27% kidney, 3% multi) received V3. Median (interquartile range [IQR]) age was 15 (14-16) years;42% were male and 78% white. pSOTRs were median (IQR) 9 (6-13) years from transplant. Four (11%) patients had prior SARS-CoV-2 infection. Antibody titers were positive in 26/37 (70%) patients pre-V3 and 32/37 (86%) post-V3 (Figure). Median (IQR) antibody titers were higher post-V3 (2500 [1581-2500] U/mL) than pre-V3 (211 [0.8-2500] U/mL) in paired analysis (p<0.001). 6/11 (55%) pSOTRs with negative pre-V3 titers seroconverted, with a post-V3 median (IQR) titer of 418 (132-1581) U/ mL. Transplant within 3 years was associated with negative post-V3 titer (p=0.037). Main side effects after V3 were pain (71%) and fatigue (50%). No patients reported allergic reaction, myocarditis, or rejection. One patient tested positive for SARSCoV- 2 between vaccines 2 and 3, with negative pre- and post-V3 titers. At time of first vaccine, this patient was transplanted a year ago, treated for rejection recently, and taking 3 immunosuppression agents including an antimetabolite. Conclusion(s): In this limited cohort, 86% of pSOTRs had a positive antibody response after three SARS-CoV-2 vaccines with no adverse events. Importantly, 55% of pSOTRs with prior negative response seroconverted post-V3, and 100% of pSOTRs with positive response increased their antibody titer or remained at maximum titer. Our preliminary results suggest the benefit of a third vaccine for adolescent pSOTRs based on antibody response;larger studies are needed to assess vaccine effectiveness.

Humoral and Cellular Immune Response to a Third Dose of SARSCoV- 2 Vaccine in Kidney Transplant Recipients on Belatacept

Purpose: Kidney transplant recipients taking belatacept (KTR-B) have poor immune response to two-dose SARS-CoV-2 vaccination. We sought to characterize the impact of an additional vaccine dose on plasma neutralizing capacity and cellular responses as compared to that of KTRs controls (KTR-C) not taking belatacept. Method(s): Within an observational cohort, we tested 26 KTR-Bs and 27 KTR-Cs for anti-spike antibody responses before and after a third SARS-CoV-2 vaccine dose (D3) using two clinical assays (Roche Elecsys anti-S Ig and EUROIMMUN anti-S1 IgG). For a subset of 5 KTR-Bs and for all KTR-Cs we used a research assay (Meso Scale Diagnostics V-Plex [MSD]) to further assess anti-spike and RBD IgG, as well as surrogate plasma neutralizing activity (% ACE2 inhibition) versus the ancestral and delta variants. For 3 KTR-Bs, post D3 T cell response was assessed via IFN-y ELISpot and deemed positive if spot forming units > 20 per million PBMC and stimulation index > 3. Result(s): KTR-Bs had significant lower clinical anti-spike seroconversion than KTR-Cs (31% vs 74%, p=0.001) after D3 despite similar demographics, clinical factors, and vaccines administered (Table 1). No KTR-B (0/5) was seropositive by MSD anti-spike or anti-RBD IgG (Figure 1). % ACE2 inhibition versus the ancestral variant was significantly lower in KTR-Bs than in KTR-Cs (Median [IQR] 5.2 [2.8, 6.5] vs 12.5 [7.7, 23.9], p<0.01);all KTR-Bs were below a level consistent with detectable neutralizing antibody. All tested KTR-Bs (3/3) had a negative ELISpot, consistent with negligible cellular response. Conclusion(s): These results suggest minimal humoral or cellular immunogenicity of additional vaccine doses for KTR-Bs and indicates the need for alternative strategies to improve vaccine response such as immunosuppression alteration or use of passive immunoprophylaxis with monoclonal anti-spike antibody to improve protection versus SARS-CoV-2.

Higher Proinflammatory Cytokines Are Associated with Increased Antibody Titer After a Third Dose of SARS-CoV-2 Vaccine in Solid Organ Transplant Recipients

Purpose: Solid organ transplant recipients (SOTRs) are at increased risk for severe COVID-19 and exhibit lower antibody responses to SARS-CoV-2 vaccines. This study aimed to determine if pre-vaccination cytokine levels are associated with antibody response to SARS-CoV-2 vaccination. Method(s): A cross-sectional study was performed among 58 SOTRs before and after two-dose mRNA vaccine series, 35 additional SOTRs before and after a third vaccine dose, with comparison to 16 healthy controls (HCs). Anti-spike antibody was assessed using the IgG Euroimmun ELISA. Electrochemiluminescence detectionbased multiplexed sandwich immunoassays were used to quantify plasma cytokine and chemokine concentrations (n=20 analytes). Concentrations between SOTRs and HCs, stratified by ultimate antibody response to the vaccine, were compared using Wilcoxon-rank-sum test with false discovery rates (FDR) computed to correct for multiple comparisons. Result(s): In the study population, 100% of HCs, 59% of SOTRs after two doses and 63% of SOTRs after three doses had a detectable antibody response. Multiple baseline cytokines were elevated in SOTRs versus HCs. There was no significant difference in cytokine levels between SOTRs with high vs low-titer antibodies after two doses of vaccine. However, as compared to poor antibody responders, SOTRs who went on to develop a high-titer antibody response to a third dose of vaccine had significantly higher pre-third dose levels of several innate immune cytokines including IL-17, IL-2Ra, IL-6, IP-10, MIP-1alpha, and TNF-alpha (FDR <0.05). Conclusion(s): A specific inflammatory profile or immune state may identify which SOTRs are likely to develop stronger sero-response and possible protection after a third dose of SARS-CoV-2 vaccine.

Pre-Vaccine Antibodies Against Seasonal Betacoronaviruses Are Associated with Decreased Antibody Response to SARS-CoV-2 mRNA Vaccination in Solid Organ Transplant Recipients

Purpose: The impact of antigenic imprinting, when immune memory of one antigen influences the response to subsequent similar antigens, on the antibody response in solid organ transplant recipients (SOTRs) after SARS-CoV-2 vaccination is currently unknown. This study examines the relationship between seasonal coronaviruses (sCoV) and SARS-CoV-2 antibody levels pre- and post-vaccination in SOTRs. Method(s): Plasma from 52 SOTRs pre- and post-SARS-CoV-2 vaccination (2 doses, mRNA) was analyzed using the Meso Scale Diagnostic Coronavirus Panel 3 (an electrochemiluminescence detection-based multiplexed sandwich immunoassay) for IgG antibodies against alpha sCoVs (229E, NL63), beta sCoVs (HKU1, OC43), and SARS-CoV-2 spike proteins. Changes in IgG titers were determined by paired Wilcoxon rank-sum tests. Spearman correlation analysis was used to determine associations between pre-vaccination anti-sCoVs and post-vaccination anti-SARS-CoV-2 IgG. Result(s): Vaccination increased both anti-SARS-CoV-2 (fold change (FC) 1.9, p<0.001) and anti-beta sCoV (HKU1 [FC 0.05, p<0.001], OC43 [FC 0.8, p<0.001]) IgG titers in SOTRs, but did not increase anti-alpha sCoV IgG. Furthermore, prevaccination anti-beta sCoV (HKU1 [rho= -0.3, p=0.03], OC43 [rho= -0.3, p<0.03]) IgG titers were negatively correlated with post-vaccination anti-SARS-CoV-2 IgG. Conclusion(s): These exploratory findings suggest that prior exposure to seasonal betacoronaviruses may lead to antigenic imprinting in SOTRs that negatively impacts the antibody response to vaccination against the novel pandemic betacoronavirus, SARS-CoV-2.

SARS-CoV2 Antibody Kinetics and Durability Three and Six Months After Two-Doses of MRNA Vaccination in Liver Transplant Recipients

Purpose: nti-spike antibody response to SARS-CoV-2 vaccination is diminished in LT recipients compared to the general population so understanding durability for those that do respond is critical to mitigating risks of infection. We measured serial antibody titers in LT recipients for 6 months after two-dose mRNA vaccine series to describe kinetics and sero-reversion rates. Method(s): LT recipients without known prior COVID-19 had anti-spike antibody testing at 1, 3, and 6 months after the second dose of mRNA vaccine (D2) using two commercial assays (Roche Elecsys anti-receptor binding domain immunoassay (EIA) [positive >=0.8 U/mL] or EUROIMMUN anti-S1 EIA [positive >=1.1 AU]). We compared titer distributions over time and identified factors associated with sero-reversion. Result(s): 180 LT recipients received BNT162b2 (48%) or mRNA-1273 (52%) 2-dose series between 1/7/2021-5/7/2021. At 1 month post-D2 (n=173), 146 (84%) had positive antibody levels at a median (IQR) of 30 (28, 32) days post-D2. At 3 months post-D2 (n=164), 149 (91%) had positive levels at a median of 92 (90, 96) days post-D2. At 6 months post-D2 (n=73), 62 (85%) had positive levels at a median of 180 (176, 185) days post-D2. Among the 66 seropositive at 1 or 3 months post-D2, 58 (88%) remained seropositive by 6 months post-D2. Neither age, years since transplant, vaccine type, nor mycophenolate (MMF) use were associated with sero-reversion, though there was a trend toward more triple immunosuppressive use (25% vs 3%, p=0.07). Of those Roche-tested, the median anti-RBD levels were >=250 U/mL (14, >=250;n=120) at 1 month post-D2, >=250 U/mL (58, >=250;n=113) at 3 months, and >=250 U/mL (30, >=250;n=49) at 6 months . Of those EUROIMMUN-tested, the median anti-S1 levels were 7.25 AU (4.31, 8.71;n=53) at 1 month, 5.71 AU (1.27, 7.90;n=51) at 3 months, and 1.73 AU (0.76, 6.01;n=25) at 6 months. Conclusion(s): Overall, most LT recipients demonstrated 6 month durability of anti-spike antibody following vaccination, but a subset did sero-revert, potentially associated with heavier immunosuppression. Further investigation into clinical consequences of waning antibody levels is key to guide timing of additional vaccine doses.

Three Month Antibody Durability and Kinetics in SARS-CoV-2 Mrna Vaccinated Heart and Lung Transplant Recipients: Differences Above the Diaphragm

Purpose: Heart and lung transplant (HT/LT) recipients have impaired humoral responses to SARS-CoV-2 vaccination compared to other solid organ transplant recipients (SOTRs). The purpose of this study is to describe antibody titer kinetics and durability among HT and LT recipients. Method(s): HT or LT recipients (> 18 years) with no known COVID-19 infection were included. Demographics and clinical characteristics were collected via survey. Serologic testing was performed on the Roche Elecsys anti-SARS-CoV-2 enzyme immuno-assay (EIA) or the EUROIMMUN EIA pre- and post-dose 2 (D2). Result(s): Among 93 HT recipients, 59 (63%) were seropositive 1 month and 66 (71%) 3 months post-D2 (Table 1). Seropositive HT recipients had a higher median length of time from transplant to vaccination. 7/66 (11%) had delayed seroconversion (were negative for antibodies 1-month post-D2). Median(IQR) anti-RBD was 81 (8, 250) 1-month post-D2 (n=38) and 231 (48, 438) U/mL 3-months post-D2 (n=43) (Figure 1). Among 68 LT recipients, 29/68 (43%) were seropositive 1-month and 30 (44%) 3-months post-D2. Seronegative LT recipients were more likely to younger (18-39 years old, 15% vs 3%), or older (> 60 years, 74% vs. 50%, p=0.01). Seronegative LT recipients were more likely to be on anti-metabolite therapy (79% vs. 53%, p=0.04) and had a lower median length of time from transplant to vaccination. Among seropositive LT recipients at 3-months, 3 (10%) had delayed seroconversion. Median (IQR) anti-RBD was 61 (4, 233) U/mL 1-month post-D2 (n=26) and 45(11, 299) U/mL 3-months post-D2. Conclusion(s): HT and LT recipients develop a delayed and variable antibody response to mRNA SARS-CoV-2 vaccination. HT recipients more frequently seroconverted, and had higher anti-RBD levels, than LT recipients. Persistent negative and low antibody titers may place LT recipients at the highest risk of breakthrough SARSCoV- 2 infection among SOTRs.

Six-Month Antibody Kinetics and Durability After Three Doses of SARS-CoV-2 Vaccine in Solid Organ Transplant Recipients

Purpose: Some solid-organ transplant recipients (SOTRs) with low or negative antibody levels after a 2-dose mRNA vaccine series against SARS-CoV-2 experience boosting after a third dose (D3), but long-term antibody durability after D3 is unknown. We describe six-month SARS-CoV-2 antibody kinetics and durability in 31 SOTRs who received D3. Method(s): 31 SOTRs without prior COVID-19 were identified within our national observational study. Serologic testing was performed a median of 30 (IQR 27-40) days after D3 and repeated at a median of 166 (148-184) days after D3. Semiquantitative anti-spike serologic testing using the Roche Elecsys anti-S enzyme immunoassay (EIA) or EUROIMMUN anti-S1 EIA was performed. Result(s): Over 6 months of follow-up, antibody levels increased in 16/27(59%), remained stable in 6/27(22%) (one negative, the others above the assay limit), and decreased in 5/27(19%). One-month post-D3, 24/31(77%) were seropositive and 7/31(23%) were seronegative. Six-months post-D3, 29/31(94%) were seropositive and 2/31(6%) remained seronegative. Both nonresponders received the BNT-162b2 primary series;one received Ad.26.CoV2.S and the other mRNA-1273 for D3. This difference in seroconversion after D3 was not statistically significant (Fisher exact = 0.49, between primary series). There were no reported cases of COVID-19 during the study period. Conclusion(s): We observed a very high rate of seroconversion after D3 in SOTRs, with marked heterogeneity in timing and strength of response depending on baseline antibody level and vaccine platform received. These results are encouraging evidence for the durable immunogenicity of additional vaccine doses in most SOTRs, and demonstrate the need for dedicated analysis of heterologous boosting strategies.

B Cells Fit for Germinal Center Activity Predict Response to a Third Dose of SARS-CoV-2 Vaccine in Solid Organ Transplant Recipients

Purpose: While SARS-CoV-2 vaccination has dramatically reduced COVID-19 severity in the general population, fully vaccinated solid organ transplant recipients (SOTRs) demonstrate reduced seroconversion and increased breakthrough infection rates. Furthermore, a third vaccine dose only increases antibody and T cell responses in a proportion of SOTRs. We sought to investigate the underlying mechanisms resulting in varied humoral responses in SOTRs. Method(s): Within a longitudinal prospective cohort of SOTRs, anti-spike IgG, total and spike-specific B cells were evaluated in 44 SOTR participants before and after a third vaccine dose using high dimensional flow cytometry to assess immunologic and metabolic phenotypes. B cell phenotypes were compared to those of 10 healthy controls who received a standard two-dose mRNA series. Result(s): Notably, even in the absence anti-spike antibody after two doses, spikespecific B cells were detectable in most SOTRs (76%). While 15% of participants were seropositive before the third dose, 72% were seropositive afterward. B cells, however, were differentially skewed towards non-class switched B cells in SOTRs as compared to healthy control B cells. Expansion of spike-specific class-switched B cells in SOTRs following a third vaccine dose correlated with increased classswitched (IgG) antibody titers. Antibody response to a third vaccine dose was associated with expanded populations of germinal center-like (CD10+CD27+) B cells, as well as CD11c+ alternative lineage B cells with specific upregulation of CPT1a, the rate limiting enzyme of fatty acid oxidation and a preferred energy source of germinal center B cells. Conclusion(s): This analysis defines a distinct B cell phenotype in SOTRs who respond to a third SARS-CoV-2 vaccine dose, specifically identifying fatty acid oxidation as pathway that could be targeted to improve vaccine response such as through targeted immunosuppressive modulation. (Figure Presented).

Effect of Mycophenolate Mofetil Dosing on Antibody Response to SARS-CoV-2 Vaccination in Heart and Lung Transplant Recipients

Purpose: Mycophenolate mofetil (MMF) use is associated with decreased antibody response to the SARS-CoV-2 mRNA vaccine series in heart and lung transplant recipients (HLTRs). Higher MMF doses have been associated with poor immunogenicity in kidney transplant recipients, but limited data exist on HLTRs. We evaluated the relationship between daily MMF dose and vaccine-induced antibody response in HLTRs. Method(s): HLTRs (n= 212) from an observational cohort were categorized by daily MMF doses (None, Low: <1000mg, Moderate: 1000-2000mg, High: >=2000mg). Semi-quantitative antibody testing was performed at 1, 3, and 6-months post-dose 2 (D2) using the Roche Elecsys anti-SARS-CoV-2 S enzyme immunoassay (EIA), testing for antibodies to SARSCoV2 spike protein receptor binding domain, and the EUROIMMUN EIA, testing for S1 domain of SARS-CoV-2 spike protein. Multivariable Poisson regression was used to estimate the risk of a negative antibody response with increasing MMF dose. Result(s): At the time of vaccination, 94 (44.3%) HLTRs reported receiving no MMF, 33 (15.6%) reported a low dose, 54 (25.7%) reported a moderate dose, and 31 (14.8%) reported a high dose regimen. There were statistically significant differences in the number of participants on mTOR inhibitors and Triple immunosuppression among the groups but the participants in all 4 dose categories were otherwise comparable (Table 1) The risk ratio of a negative post-D2 titer with low, moderate and high dose regimens compared to no MMF was 0.65 1.15 2.05 (p=0.63), 1.34 2.043.10 (p=0.001) and 1.83 2.77 4.21 (p<0.001) after adjusting for age, sex, vaccine type, time since transplant, and corticosteroid use. Conclusion(s): HLTRs taking MMF >1000mg/day are at higher risk of remaining seronegative after mRNA vaccination, with evidence of a dose-nonresponse effect. The findings support the exploration of whether targeted MMF reduction strategies in HLTRs increase SARS-CoV-2 vaccine immunogenicity. (Table Presented).

A Machine Learning Model for Predicting Antibody Response to 2-Dose SARS-CoV-2 MRNA Vaccine Series in Transplant Recipients

Purpose: Understanding risk factors for impaired vaccine responses can guide strategies for testing, additional dose recommendations, and vaccine schedules to provide improved protection in solid organ transplant recipients (SOTRs). Our purpose was to use machine learning to characterize risk factors and create a prediction model for seroconversion after 2-dose mRNA SARS-CoV-2 vaccination. Method(s): Using our national observational cohort of 1031 SOTRs we created a machine learning model using gradient boosting to explore, rank, and quantify the association of 19 clinical factors with antibody responses to 2-dose mRNA vaccination. Gradient boosting is a general-purpose machine learning algorithm that generates a sequence of parsimonious prediction models based on the residual error of the previous models. We measured the area under the receiver operating characteristic curve (AUROC) via a 10-fold cross validation to evaluate the model's performance. Finally, we evaluated the prediction performance of the models in discrimination and calibration with an external cohort of 512 SOTRs from Houston Methodist. Result(s): Mycophenolate mofetil (MMF) use, shorter time since transplant, and older age were the strongest predictors of seronegativity, collectively contributing to 76% of the model's prediction performance (Figure 1). Other clinical factors, including organ type, vaccine type, sex, race, and other immunosuppression medications, showed weaker associations with seronegativity. Longer time since transplant was associated with higher odds of seropositivity, especially during the first 5 years post-transplant (Figure 2a). Older age among those <65 years old (Figure 2b) and MMF (Figure 2c) were associated with lower odds of seropositivity. The model had moderate prediction performance, with an AUROC of 0.79 (our cohort) and 0.67 (Houston Methodist cohort). Conclusion(s): Our machine learning model allows us to identify SOTRs at highest risk of suboptimal immunogenic response to vaccination, highlighting opportunities for improving protection from COVID-19 including more targeted vaccination strategies. (Figure Presented).

Better Antibody Response After a Dose of Ad.26.cov2.s vs MRNA Vaccines in Seronegative Transplant Recipients After 2-Dose MRNA Vaccination

Purpose: To compare antibody response to a third dose (D3) of SARS-CoV-2 vaccine in solid organ transplant recipients (SOTRs) with negative or low-positive antibody levels after 2-dose mRNA vaccination across D3 platforms. Method(s): From our observational study, 532 SOTRs who developed suboptimal antibody responses to 2-dose mRNA vaccination (Roche<50 U/mL or EUROIMMUN <1.1 AU) were selected. Belatacept recipients and persons with any COVID-19 diagnosis were excluded. We compared post-D3 antibody levels among SOTRs who received an mRNA vaccine for D3 (n=487) versus Ad.26.COV2.S for D3 (n=45). Poisson regression with robust standard error was used to study the association between vaccine platform and seroconversion, adjusting for immunosuppression, age, time since transplant, and liver transplant status. Result(s): Pre-D3, 342 SOTRs (64%) were seronegative, of whom 107 (31%) developed high-positive antibody levels post-D3. In contrast, of the 190 (36%) with low-positive pre-D3 antibody levels, 172 (91%) were high-positive post-D3 (Figure 1). Among SOTRs seronegative pre-D3, 1.8x more Ad.26.COV2.S D3 recipients seroconverted compared to mRNA D3 recipients (49.7% vs 27.8%, Fisher's exact=0.014) (Figure 2). Among the pre-D3 seronegative group, there was a 2x higher chance of developing high-positive post-D3 levels with Ad.26.COV2.S compared to mRNA D3 (IRR =1.42.02.9, p<0.001). This was despite the Ad.26. COV2.S D3 group having fewer younger patients and liver transplant recipients, factors that are associated with higher odds of positive antibody response. 165 SOTRs (31%) remained seronegative after D3 (22% of Ad.26.COV2.S recipients vs 32% of mRNA recipients). Conclusion(s): Heterologous boosting with Ad.26.COV2.S may be a promising vaccination option for SOTRs with poor response to the 2-dose mRNA series, particularly among those who are seronegative. (Table Presented).

Post-Acute Sequelae of Sars-Cov-2 Infection in Solid Organ Transplant Recipients

Purpose: Post-acute sequelae of SARS-CoV-2 infection (PASC) is an increasingly recognized phenomenon manifested by long lasting cognitive, mental, and physical symptoms. We aimed to estimate the prevalence of PASC symptoms in solid organ transplant recipients (SOTRs) in the short (1- 6 months) and long-term (> 6 months) periods after SARS-CoV-2 infection. We also compared the prevalence of these symptoms between those with SARS-CoV-2 infection requiring hospitalization and those not requiring hospitalization. Method(s): We surveyed 111 SOTRs with self-reported SARS-CoV-2 infection diagnosed more than 4 weeks prior to survey administration. The survey consisted of 7 validated questionnaires ("Quick Dementia Rating System (QDRS)", "Patient Health Questionnaire (PHQ9)", "Generalized Anxiety Disorder 7 (GAD-7)", "Impact of Events Scale (IES-6)", "EuroQol- 5 Dimension (EQ-5D)", "PROMIS global physical health scale (GHS) "and "Breathlessness, Cough and Sputum Scale (BCSS)"). Result(s): Of the 111 survey participants, 32 (33%) had been hospitalized and 35 (36%) had SARS-CoV-2 infection >6 months ago. Median (IQR) age was 58 years (46, 65). Median time from SARS-CoV-2 diagnosis was 167 days (138, 221). Cognitive impairment, anxiety, depression, insomnia, feeling of trauma, fatigue, pain, breathing problems, cough, abnormal smell, abnormal taste, and diarrhea were reported by 40%, 23%, 36%, 55%, 53%, 41%, 19%, 33%, 33%, 21%, 22%, and 32% of patients respectively. Hospitalized patients had poorer scores in cognition (QDRS survey score of 2 versus 0.75, p=0.048) (Figure 1), quality of life (EQ-5D survey score of 2 versus 1, p=0.043), physical health (PROMIS GHS survey score of 10 versus 11, p=0.013), respiratory status (BCSS survey score of 1 versus 0, p=0.056), and pain (Pain score of 3 versus 0, p 0.006). Among patients who had SARS-CoV-2 infection >6 months ago, abnormal breathing, cough, abnormal smell, abnormal taste, and diarrhea continued to be reported by 31%, 31%, 29%, 32%, and 32% of patients respectively. Conclusion(s): After SARS-CoV-2 infection, SOTRs had a high prevalence of PASC symptoms. Some of the symptoms are more severe in patients who had required hospitalization and persist beyond 6 months. Further studies are needed to understand the long term sequalae of SARS-CoV-2 infection in SOTRs and to develop an evidence-based multidisciplinary approach for caring for these patients beyond the acute phase. (Table Presented).