ABSTRACT
Background. Vaccine-induced SARS-CoV-2 antibody responses are reduced in patients taking lymphocyte-depleting therapies, which are commonly prescribed for patients with idiopathic inflammatory myopathies (IIM). While a third vaccine dose (D3) augments the SARS-CoV-2 anti-spike response in some patients, there is a paucity of data on the humoral response following D3 in patients with IIM. Furthermore, the durability of antibody response is unknown. In this study, we evaluated serial antibody response for three months following a 3rd dose SARS-CoV-2 vaccination in IIM patients. Methods. Adults with a patient-reported diagnosis of idiopathic inflammatory myopathy who completed three-dose SARS-CoV-2 vaccination (two-dose BNT162b2 or mRNA-1273 followed by single mRNA or adenoviral vector dose) were recruited via social media campaign. Demographics and clinical characteristics were collected via patient report. Informed consent was provided electronically. Serial antibody responses were evaluated by the Roche Elecsys anti-SARS-CoV-2 S enzyme immunoassay, which measures total antibody to the SARS-CoV-2 S-receptor binding domain (RBD) protein (range 0. 4-2500U/ mL;positive >0.8U/mL). Poor antibody response was defined as anti-RBD titer <500U/mL based on predicted correlates of protective plasma neutralizing capacity. Those with prior COVID-19 infection were excluded. Associations were evaluated using Fisher's exact and Wilcoxon rank-sum tests as appropriate. Results. We evaluated serial anti-RBD titers in 59 participants (Table I). Most (93%) were female with median (IQR) age of 51 (41-62) years. Mycophenolate mofetil was the most frequently prescribed medication (45.6%). Participants completed primary vaccination with two-dose BNT162b2(54%) or mRNA-1273(46%). Median pre-D3 anti-RBD titer (IQR) was 65.8U/mL (4.6,473) at 158 (136-183) days following primary vaccination. Dose 3 included BNT162b2(47%), mRNA-1273(47%) or Ad.26.COV2.S (6%). Most (89.9%) received homologous D3 vaccination. 39% of participants reported holding peri-D3 immunosuppression with mycophenolate mofetil being the most commonly held medication in the peri-D3 period. Repeat anti-RBD testing was performed at a median (IQR) 30 (28-32) days post-D3. A higher antibody titer was seen in 89.9% participants following D3 with median (IQR) titer of 2500 U/mL (92,2500). Thirty-seven percent remained <500U/mL following D3;a greater proportion of these participants reported use of rituximab and greater number of immunosuppressive therapies compared to those with anti-RBD >=500U (72.7% versus 5.4%, p<0.001;3 therapies versus 2 therapies, p=0.03). Furthermore, 13.5% (8/59) remained below the threshold of positivity following D3;7/8 reported use of rituximab, 5/8 mycophenolate mofetil, or combination of these agents (4/8). There was not a significant difference in antibody titers among recipients of homologous/heterologous vaccination (p=0.22). Dose 3 was well tolerated with only 2 (3.4%) participants reporting disease flare requiring treatment within one month of vaccination;neither required intravenous therapy or hospital admission. Thirty-four (57.6%) participants underwent repeat anti-RBD testing three months following D3 with median (IQR) 2500U/mL (456,2500);73.53% (25/34) remained above threshold of >=500U/mL. Limitations of this study include small sample size and absence of healthy control group. Diagnosis was based on participant report and we did not routinely collect information on disease activity. Conclusion. We observed an augmented humoral response in most IIM patients following 3rd dose SARS-CoV-2 vaccination;antibody response was durable at three months. Dose 3 was well tolerated. Over 1/3 participants failed to develop adequate response following D3, namely those on rituximab therapy and on higher number of immunosuppressive therapies. These patients should be prioritized for prophylactic therapies to enhance protection against COVID-19 infection.
ABSTRACT
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.
ABSTRACT
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).
ABSTRACT
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).
ABSTRACT
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).
ABSTRACT
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).