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2.
Clinical Transplantation ; : e14913, 2023.
Article in English | MEDLINE | ID: covidwho-2192504

ABSTRACT

BACKGROUND: Tixagevimab and Cilgavimab (T+C) is authorized for pre-exposure prophylaxis (PrEP) against COVID-19 in solid organ transplant recipients (SOTRs), yet patient-reported outcomes after injection are not well described. Furthermore, changes in risk tolerance after T+C PrEP have not been reported, of interest given uncertain activity against emerging Omicron sublineages.

3.
Transplantation Direct ; 9(1), 2023.
Article in English | Web of Science | ID: covidwho-2191241

ABSTRACT

Background.Following the outbreak of coronavirus disease 2019 (COVID-19) in the United States, the number of kidney waitlist additions and living-donor and deceased-donor kidney transplants (LDKT/DDKT) decreased substantially but began recovering within a few months. Since then, there have been several additional waves of infection, most notably, the Delta and Omicron surges beginning in August and December 2021, respectively. Methods.Using SRTR data, we compared observed waitlist registrations, waitlist mortality, waitlist removal due to deteriorating condition, LDKT, and DDKT over 5 distinct pandemic periods to expected events based on calculations from preepidemic data while accounting for seasonality and secular trends. Results.Although the number of daily waitlist additions has been increasing since May 2020, the size of the active waitlist has consistently declined, reaching a minimum of 52 556 on February 27, 2022. The recent Omicron surge knocked LDKT from 25% below baseline (incidence rate ratio [IRR] = (0.69)0.75(0.81)) during the Delta wave to 38% below baseline (IRR = (0.58)0.62(0.67)). DDKT, however, was less affected by the Omicron wave (IRR = (0.85)0.89(0.93) and (0.88)0.92(0.96) during the Delta and Omicron waves, respectively). Waitlist death decreased from 56% above baseline (IRR = (1.43)1.56(1.70)) during Delta to 41% above baseline during Omicron, whereas waitlist removal due to deteriorating condition remained at baseline/expected levels during the Delta wave (IRR = (0.93)1.02(1.12)) and the Omicron wave (IRR = (0.99)1.07(1.16)). Conclusions.Despite exceptionally high COVID-19 incidence during the Omicron wave, the transplant system responded similarly to prior waves that imposed a lesser disease burden, demonstrating the transplant system's growing adaptations and resilience to this now endemic disease.

5.
American Journal of Transplantation ; 22(Supplement 3):640-641, 2022.
Article in English | EMBASE | ID: covidwho-2063541

ABSTRACT

Purpose: Kidney transplant recipients (KTRs) have diminished immune response and protection after 2-dose mRNA COVID-19 vaccination. It is unknown if additional doses improve neutralization of variants of concern (VOC) in KTRs with prior poor seroresponse. Method(s): Adult KTRs with negative (<0.8 U/mL) or low (<=50 U/ml) anti-RBD Ig (Roche Elecsys anti-SARS-CoV-2-S) after 2-dose mRNA series were given a homologous 3rd dose (D3). Anti-RBD and VOC surrogate neutralization (%ACE2i) were measured 30 days post D3;responses were stratified by baseline anti-RBD. Reactogenicity, serial SARS-CoV-2 swabs, and donor-specific antibody (DSA) were assessed. Result(s): 81 KTRs (50% negative anti-RBD) received D3 (72% BNT162b2, 28% mRNA-1273) at median 167 days post D2 (Table). Median (IQR) anti-RBD increase was 410 (8-2309) U/mL with 69% (40% negative vs 98% low anti-RBD) achieving day 30 anti-RBD >50 U/ml (Fig1a). 22% remained seronegative. Non-response was associated with lower baseline lymphocyte count (median 770 vs 1160 cells/ uL;p=0.05) and IgG (median 779 vs 979 mg/dL;p<0.01), but not demographics, vaccine, or immunosuppressives. Median (IQR) delta variant %ACE2i increased from 6% (3-7) to 10% (4-22) (p<0.001), a 1% (0-5) increase in negative vs 13% (5-25) in low anti-RBD. %ACE2i was linearly associated with anti-RBD >=100 U/ mL (all VOC shown in Fig1b);64% of KTRs with anti-RBD >=250 U/mL had delta %ACE2i >20. There were 3 cases of mild-moderate COVID-19 >=7 days post-D3, with pre-infection anti-RBD <0.4, 22, 76 U/mL and delta %ACE2i 6, 9, and 16, respectively. There was no acute rejection, nor increased or de novo DSA. Conclusion(s): A 3rd mRNA vaccine dose increased anti-RBD and VOC neutralization in KTRs without inducing clinical alloimmunity, yet 45% with negative baseline anti-RBD remained seronegative without delta variant neutralization. Trials are ongoing to test immune response augmentation in this subgroup via temporary immunosuppression reduction or heterologous boosting.

6.
American Journal of Transplantation ; 22(Supplement 3):1060, 2022.
Article in English | EMBASE | ID: covidwho-2063522

ABSTRACT

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.

7.
American Journal of Transplantation ; 22(Supplement 3):641-642, 2022.
Article in English | EMBASE | ID: covidwho-2063495

ABSTRACT

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.

8.
American Journal of Transplantation ; 22(Supplement 3):766, 2022.
Article in English | EMBASE | ID: covidwho-2063482

ABSTRACT

Purpose: This study compares SARS-CoV-2 antibody responses between the twodose mRNA-1273 and BNT162b2 vaccine series across groups of incrementally immunosuppressed patients. Method(s): Semiquantitative testing for antibodies against the receptor binding domain (RBD) of the SARS-CoV-2 spike protein was performed using the Roche Elecsys anti-SARS-CoV-2 S enzyme immunoassay (EIA), 15-45 days after the second vaccine dose for SARS-CoV-2 naive patients with rheumatic and musculoskeletal disease (RMD), and solid organ transplant recipients (SOTRs) from an observational cohort. Anti-RBD titers were divided into categories of >=50, >=100 and >=250 U/mL based on levels associated with plasma neutralizing capacity in COVID-19 convalescent patients. Participants were stratified by increasing intensity of immunosuppression: RMD not on immunosuppression, RMD on immunosuppression, SOTR not on mycophenolate (MMF), and SOTR on MMF. Response rates between mRNA-1273 and BNT162b2 recipients were compared using modified Poisson regression weighted for age, time since vaccination, and number of immunosuppressive medications. This analysis was repeated for several thresholds of positive response: 50, 100, and 250 U/mL. Result(s): Of 1868 participants, 55.8% of RMD and 52.7% of SOTRs received BNT162b2;the remainder received mRNA-1273. Demographics, diagnoses, and immunosuppressive regimens were similar across vaccine groups. Among RMD participants not on immunosuppression, the chance of anti-RBD >=250U/ml was comparable among BNT162b2 and mRNA-1273 recipients (IRR= 0.91 1.03 1.16 p= 0.67). mRNA-1273 recipients had a higher chance than BNT162b2 recipients to achieve anti-RBD >=250U/ml among RMD participants on immunosuppression (IRR = 1.15 1.241.34, p<0.001);SOTRs not on MMF (IRR = 1.24 1.561.96, p <0.001);and SOTRs on MMF (IRR=1.28 2.625.37, p= 0.01). Similar trends were observed with titer cutoffs of >=100 and >=50 U/mL (Table 1). Conclusion(s): The two-dose mRNA-1273 vaccine series was more likely to induce stronger humoral immunogenicity compared to BNT162b2 in immunosuppressed patients;this effect was more pronounced with greater immunosuppression. These findings suggest importance in the choice of mRNA vaccine platform in optimizing immune responses to SARS-CoV-2 vaccination and can help inform vaccination strategies for booster doses in high-risk, immunosuppressed populations.

9.
American Journal of Transplantation ; 22(Supplement 3):763, 2022.
Article in English | EMBASE | ID: covidwho-2063481

ABSTRACT

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.

10.
American Journal of Transplantation ; 22(Supplement 3):637-638, 2022.
Article in English | EMBASE | ID: covidwho-2063471

ABSTRACT

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.

11.
American Journal of Transplantation ; 22(Supplement 3):770, 2022.
Article in English | EMBASE | ID: covidwho-2063470

ABSTRACT

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.

12.
American Journal of Transplantation ; 22(Supplement 3):872-873, 2022.
Article in English | EMBASE | ID: covidwho-2063469

ABSTRACT

Purpose: Humoral response to COVID-19 vaccines is attenuated in many solid organ transplant recipients (SOTRs), necessitating additional primary and booster vaccinations. The omicron variant demonstrates substantial immune evasion, and it is not known if boosters increase neutralizing capacity versus omicron among SOTRs. We therefore investigated SOTR antibody response and neutralization versus variants of concern (VOC) including omicron to a 4th vaccine dose (D4). Method(s): Within a national, prospective observational cohort, 25 SOTRs underwent anti-SARS-CoV-2 spike and receptor binding domain (RBD) IgG testing using the Meso Scale Discovery platform before and 2-4 weeks after D4. Surrogate neutralization (%ACE2 inhibition [%ACE2i], range 0-100% with >20% correlating with live virus neutralization), was measured versus full spike proteins of the ancestral ("vaccine") strain and 5 VOCs including delta and omicron. Change in IgG level and %ACE2i were compared using paired Wilcoxon rank-sum testing. Result(s): Demographics are outlined in Table 1, including median (IQR) age 59 (45- 55) years, 64% kidney recipients, and D4 receipt (60% Moderna, 40% Pfizer) median (IQR) 93 days (28-134) post D3. Two participants had SARS-CoV-2 exposure per anti-nucleocapsid testing, including one incident infection. Overall, anti-RBD (92%- >100%) and anti-spike (84%->92%) seropositivity increased after D4, as did median (IQR) anti-spike IgG 42.3 (4.9-134.2)->228.9 (115.4-655.8) WHO binding antibody units (p<0.05). Median (IQR) %ACE2i significantly increased after D4 vs the vaccine strain 5.8% (0-16.8)->20.6% (5.8-45.9) and delta variant 9.1% (4.9-12.8)->17.1% (10.3-31.7) (both p<0.001). In contrast, no SOTR showed neutralization vs omicron before or after D4: median (IQR) %ACE2i 4.1% (0-6.9)->0.5% (0-5.7) (p=0.11). Conclusion(s): Although a 4th vaccine dose increased anti-spike IgG and neutralizing capacity vs some VOC, there was no omicron variant neutralization among SOTRs. SOTRs may remain at high risk for SARS-CoV-2 infection despite boosting, thus additional protective interventions should be urgently explored. (Figure Presented).

13.
American Journal of Transplantation ; 22(Supplement 3):794-795, 2022.
Article in English | EMBASE | ID: covidwho-2063468

ABSTRACT

Purpose: Solid organ transplantation decreased during the SARS-CoV-2 pandemic largely due to temporary shutdowns. The pandemic revealed significant gaps in medical knowledge among the public;disinformation, distrust, and the advent of SARS-CoV-2 may have lingering effects on transplantation rates. We hypothesize that the SARS-CoV-2 pandemic has influenced interest in living kidney donation (LKD) among members of the public. Method(s): We surveyed 900 US adults (ages 25-65) in June 2021 about LKD knowledge, attitudes, perceived barriers/facilitators, and impact of the pandemic on their interest in LKD. We evaluated the relationships between self-reported characteristics and interest in LKD using Chi-square tests. Result(s): The experience of the SARS-CoV-2 pandemic increased interest in LKD for 12% of participants, decreased interest for 9%, and had no impact for 79%. Increased interest in LKD was significantly associated with White race (White only vs. Asian only: 12.4% vs. 9.4%, p=0.005), younger age (25-34 vs. 55-65: 16.7% vs. 6.1%, p<0.0001 and 35-44 vs. 55-65: 15.9% vs. 6.1%, p<0.0001), male gender (16.3% vs. 8.5%, p= 0.001), higher income ($100,000-149,000 vs. <$50,000: 18.9% vs. 7.5%, p=0.0008), and higher educational attainment (4-year degree vs. some college: 14.4% vs. 6.07%, p=0.0012 and post-graduate degree vs. some college: 21.5% vs. 6.1%, p= <0.0001). Conclusion(s): The SARS-CoV-2 pandemic only impacted 21% of participants' interest in LKD, highlighting an unexpected externality of the pandemic. These findings unveil new opportunities for community engagement and population groups to target in future education and outreach campaigns.

14.
American Journal of Transplantation ; 22(Supplement 3):643, 2022.
Article in English | EMBASE | ID: covidwho-2063436

ABSTRACT

Purpose: Understanding the dynamics of antibody response to a third dose (D3) of anti-SARS-CoV-2 vaccine in solid organ transplant recipients (SOTRs) is important to inform booster strategies. Method(s): We studied the the dynamics of anti-RBD (Roche, <0.8 to >2500 U/dL) and anti-S (Euroimmun, 0.1 to >8.9 AU) antibody levels in a cohort of SOTRs at 2 weeks, 1 month and 3 months after D3. We compared the proportion of seroconversion at 1 month or 3 months after D3 between mRNA and Ad.26.COV2.S D3 recipients, using Poisson regression with robust standard error, adjusting for age and numbers of immunosuppressants. Result(s): Among 928 SOTRs with 2-week (n=655), 1-month (n=651) or 3-month (n=404) post-D3 titer, 78%, 82% and 86% tested positive for antibodies. The median (IQR) anti-RBD at the three timepoints were >2500 (73, >2500), 2494 (49, >2500) and 1234 (59, >2500) U/mL (Figure 1A, blue), and there were 61% (n=436), 60% (n=491) and 53% (n=313) with anti-RBD> 1000 u/mL, respectively. The median (IQR) anti-S at the three timepoints were 3.2 (0.3, 8.4), 8 (2, >8.9) and 7.4 (2, >8.9) AU (Figure 1B, blue), and there were 47% (n=218), 61% (n=161) and 64% (n=91) who developed anti-S>4 AU. Among patients with no or minimal immune response at 2 weeks post-D3 (n=102), 3/41 (7%) had increased anti-RBD by 1 month while 11/18 (61%) had increased anti-S (Fisher exact p<0.001). 6/29 (21%) had increased anti-RBD by 3 months while 12/20 (60%) had increased anti-S (p<0.01) (Figure 1A&B, yellow). 27/102 (27%) of them seroconverted at 1 or 3 months after D3. Having received Ad.26.COV2.S as D3 is associated with 3.9X increased proportion of seroconversion at 1 month or 3 months among patients with no or minimal immune response at 2 weeks after D3 (aIRR=2.223.926.92, p<0.001). Conclusion(s): Among SOTRs who received a booster anti-SARS-CoV-2 vaccination, dynamics of Anti-RBD and Anti-S antibodies differed substantially. Anti-RBD titers on average declined only slightly after 14 days post-D3, while anti-S increased up through 30-60 days post-D3. After the peak, average titer values for both antibodies declined slightly through three months post-D3.

15.
American Journal of Transplantation ; 22(Supplement 3):768-769, 2022.
Article in English | EMBASE | ID: covidwho-2063432

ABSTRACT

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.

16.
American Journal of Transplantation ; 22(Supplement 3):762, 2022.
Article in English | EMBASE | ID: covidwho-2063411

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.

17.
American Journal of Transplantation ; 22(Supplement 3):1064-1065, 2022.
Article in English | EMBASE | ID: covidwho-2063403

ABSTRACT

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.

18.
American Journal of Transplantation ; 22(Supplement 3):457, 2022.
Article in English | EMBASE | ID: covidwho-2063392

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).

19.
American Journal of Transplantation ; 22(Supplement 3):440, 2022.
Article in English | EMBASE | ID: covidwho-2063372

ABSTRACT

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).

20.
American Journal of Transplantation ; 22(Supplement 3):349-350, 2022.
Article in English | EMBASE | ID: covidwho-2063356

ABSTRACT

Purpose: Lung transplant recipients (LTRs) are less likely than other solid organ transplant recipients (SOTRs) to develop an antibody response to SARS-CoV-2 vaccination. Mycophenolate has been associated with impaired humoral response to SARS-CoV-2 vaccination, leaving these patients vulnerable to infection. Perivaccination antimetabolite hold has been an effective strategy for some patients with rheumatic and musculoskeletal diseases. In this study, we describe the safety and efficacy of a peri-vaccination antimetabolite hold in LTRs on SARS-CoV-2 anti-spike protein development following a third vaccine dose. Method(s): We studied LTRs on mycophenolate or azathioprine based antimetabolite therapy (AMT) >1-year post-LT with no history of acute cellular or humoral rejection who received SARS-CoV-2 vaccine Dose 3 (D3) May-October 2021. Patients were instructed to hold AMT 1 week before and 2 weeks after D3. Antibody titers were measured pre- and post-D3 (Roche Elecsys or DiaSorin Liaison anti-S EIA). Safety was evaluated using donor specific antibody (DSA) trend and lung biopsy results. Result(s): Of 40 participants, 30 held AMT and 10 did not hold AMT. Median (IQR) time since transplant was 3.9 years (1.9-7.3). Median (IQR) time between vaccine dose 2 and D3 was 163 days (143- 180). Among participants seronegative pre-D3, seroconversion post-D3 occurred in 52% (12/23) who held AMT vs. 57% (4/7) who did not hold AMT (p>0.9). Among patients with pre- and post-D3 DSA levels (N=19), increasing or de novo positive DSA was seen in 8.3% (1/12) of patients who held AMT vs. 0% of patients who did not hold AMT. For patients who underwent lung biopsy post-D3 (N=8), abnormal biopsy was seen in 0% (0/1) of patients holding AMT vs. 28.6% (2/7) not holding AMT. Conclusion(s): A three-week AMT hold by LTRs was not associated with increased rejection but also showed no significant difference in seroconversion compared to LTRs who did not hold AMT, suggesting this hold protocol is safe but not effective. Further investigation of alternative strategies is needed to protect LTRs from COVID-19 infection who do not mount effective immunoprotection following SARS COV-2 vaccination. (Table Presented).

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