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3.
Transplantation ; 106(10): e452-e460, 2022 10 01.
Article in English | MEDLINE | ID: covidwho-1948635

ABSTRACT

BACKGROUND: Solid organ transplant recipients (SOTRs) are less likely to mount an antibody response to SARS-CoV-2 mRNA vaccines. Understanding risk factors for impaired vaccine response can guide strategies for antibody testing and additional vaccine dose recommendations. METHODS: Using a nationwide observational cohort of 1031 SOTRs, we created a machine learning model to explore, identify, rank, and quantify the association of 19 clinical factors with antibody responses to 2 doses of SARS-CoV-2 mRNA vaccines. External validation of the model was performed using a cohort of 512 SOTRs at Houston Methodist Hospital. RESULTS: Mycophenolate mofetil use, a shorter time since transplant, and older age were the strongest predictors of a negative antibody response, collectively contributing to 76% of the model's prediction performance. Other clinical factors, including transplanted organ, vaccine type (mRNA-1273 versus BNT162b2), sex, race, and other immunosuppressants, showed comparatively weaker associations with an antibody response. This model showed moderate prediction performance, with an area under the receiver operating characteristic curve of 0.79 in our cohort and 0.67 in the external validation cohort. An online calculator based on our prediction model is available at http://transplantmodels.com/covidvaccine/ . CONCLUSIONS: Our machine learning model helps understand which transplant patients need closer follow-up and additional doses of vaccine to achieve protective immunity. The online calculator based on this model can be incorporated into transplant providers' practice to facilitate patient-centric, precision risk stratification and inform vaccination strategies among SOTRs.


Subject(s)
COVID-19 Vaccines , COVID-19 , Transplant Recipients , Antibodies, Viral , Antibody Formation , BNT162 Vaccine , COVID-19/prevention & control , COVID-19 Vaccines/adverse effects , Humans , Immunosuppressive Agents/adverse effects , Machine Learning , Mycophenolic Acid , SARS-CoV-2 , Vaccines , Vaccines, Synthetic , mRNA Vaccines
6.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-337703

ABSTRACT

As of 4/20/2022, approximately 23% of the eligible US population was unvaccinated. We studied COVID-19 infections during the Omicron (B.1.1.529) wave in unvaccinated US adults, stratified by pre-Omicron antibody levels. Anti-spike serologic testing was performed prior to the Omicron wave in the United States (9/23/21-11/5/21) and participants were surveilled to determine incident COVID-19. Only 12% of those who entered the wave with antibodies reported a test-confirmed COVID-19 infection, compared to 35% of those without antibodies prior to the Omicron wave. Effectiveness of these anti-RBD antibodies in this unvaccinated population was 67%. Among people with antibodies, titer did not appear to be associated with risk of test-confirmed Omicron infection.

7.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-337702

ABSTRACT

As of 4/20/2022, approximately 23% of the eligible US population was unvaccinated. We studied COVID-19 infections during the Omicron (B.1.1.529) wave in unvaccinated US adults, stratified by pre-Omicron antibody levels. Anti-spike serologic testing was performed prior to the Omicron wave in the United States (9/23/21-11/5/21) and participants were surveilled to determine incident COVID-19. Only 12% of those who entered the wave with antibodies reported a test-confirmed COVID-19 infection, compared to 35% of those without antibodies prior to the Omicron wave. Effectiveness of these anti-RBD antibodies in this unvaccinated population was 67%. Among people with antibodies, titer did not appear to be associated with risk of test-confirmed Omicron infection.

8.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-337641

ABSTRACT

Neutralizing antibody responses are attenuated in many solid organ transplant recipients (SOTRs) despite SARS-CoV-2 vaccination. Pre-exposure prophylaxis (PrEP) with the monoclonal antibody combination Tixagevimab and Cilgavimab (T+C) might augment immunoprotection, yet activity against Omicron sublineages in vaccinated SOTRs is unknown. Vaccinated SOTRs who received 300+300mg T+C (either single dose or two 150+150mg doses) within a prospective observational cohort submitted pre- and post-injection samples between 1/10/2022-4/4/2022. Binding antibody (anti-receptor binding domain [RBD], Roche) and surrogate neutralization (%ACE2 inhibition;≥20% connoting neutralizing inhibition, Meso Scale Discovery) were measured against variants including Omicron sublineages BA.1 and BA.2. Data were analyzed using the Wilcoxon matched-pairs signed-rank test and McNemar’s test. Among 61 participants, median (IQR) anti-RBD increased from 424 (IQR <0.8-2322.5) to 3394.5 (IQR 1403.9-7002.5) U/ml post T+C (p<0.001). The proportion demonstrating vaccine strain neutralizing inhibition increased from 46% to 100% post-T+C (p<0.001). BA.1 neutralization was low and did not increase (8% to 16% of participants post-T+C, p=0.06). In contrast, BA.2 neutralization increased from 7% to 72% of participants post-T+C (p<0.001). T+C increased anti-RBD levels, yet BA.1 neutralizing activity was minimal. Encouragingly, BA.2 neutralization was augmented and in the current variant climate T+C PrEP may serve as a useful complement to vaccination in high-risk SOTRs.

10.
Am J Transplant ; 22(9): 2254-2260, 2022 09.
Article in English | MEDLINE | ID: covidwho-1831928

ABSTRACT

Heterologous vaccination ("mixing platforms") for the third (D3) dose of SARS-CoV-2 vaccine is a potential strategy to improve antibody responses in solid organ transplant recipients (SOTRs), but data are mixed regarding potential differential immunogenicity. We assessed for differences in immunogenicity and tolerability of homologous (BNT162b2 or mRNA-1273; D3-mRNA) versus heterologous (Ad.26.COV2.S; D3-JJ) D3 among 377 SARS-CoV-2-infection naïve SOTRs who remained seronegative after two mRNA vaccines. We measured anti-spike titers and used weighted Poisson regression to evaluate seroconversion and development of high-titers, comparing D3-JJ to D3-mRNA, at 1-, 3-, and 6 month post-D3. 1-month post-D3, seroconversion (63% vs. 52%, p = .3) and development of high-titers (29% vs. 25%, p = .7) were comparable between D3-JJ and D3-mRNA recipients. 3 month post-D3, D3-JJ recipients were 1.4-fold more likely to seroconvert (80% vs. 57%, weighted incidence-rate-ratio: wIRR = 1.10 1.401.77 , p = .006) but not more likely to develop high-titers (27% vs. 22%, wIRR = 0.44 0.921.93 , p = .8). 6 month post-D3, D3-JJ recipients were 1.41-fold more likely to seroconvert (88% vs. 59%, wIRR = 1.04 1.411.93 , p = .029) and 2.63-fold more likely to develop high-titers (59% vs. 21%, wIRR = 1.38 2.635.00 , p = .003). There was no differential signal in alloimmune events or reactogenicity between platforms. SOTRs without antibody response after two mRNA vaccines may derive benefit from heterologous Ad.26.COV2.S D3.


Subject(s)
2019-nCoV Vaccine mRNA-1273 , BNT162 Vaccine , COVID-19 , Influenza Vaccines , Organ Transplantation , 2019-nCoV Vaccine mRNA-1273/adverse effects , Antibodies, Viral , BNT162 Vaccine/adverse effects , COVID-19/epidemiology , COVID-19/prevention & control , COVID-19 Vaccines/adverse effects , Humans , Organ Transplantation/adverse effects , RNA, Messenger/genetics , SARS-CoV-2 , Transplant Recipients , Vaccination
17.
Frontline Gastroenterol ; 12(7): 545-549, 2021.
Article in English | MEDLINE | ID: covidwho-1533064

ABSTRACT

BACKGROUND: The endoscopic appearance of oesophageal varices determines the need for prophylaxis. However, as the point prevalence of varices is low (25%), the majority of surveillance endoscopies are unnecessary and costly. Narrow diameter, ultrathin (UT) endoscopes are more tolerable than conventional upper gastrointestinal (UGI) endoscopes and can be used without sedation. We hypothesised that unsedated UT endoscopy for variceal surveillance could be implemented during the routine outpatient clinic visit allowing accurate diagnosis of varices and the timely provision of prophylaxis. METHODS: Patients with cirrhosis awaiting surveillance endoscopy were identified. UT endoscopy was scheduled during routine clinic review at the same time as ultrasound surveillance for hepatocellular carcinoma. UGI endoscopy was performed unsedated using the E.G Scan II disposable endoscope. Varices were graded using the modified Paquet classification. Video recordings of procedures were reviewed by blinded assessors and agreement was assessed using the kappa statistic. RESULTS: 40 patients (80% male) underwent unsedated UT endoscopy. All procedures were successful and tolerated well in 98% of cases. Median procedure time was 2 min (IQR 1-3). Varices were found in 37.5% (17.5% grade 1 and 20% grade 2). Patients with grade 2 varices were prescribed non-selective beta blockers at the clinic appointment. Kappa statistic for the finding of any varices was 0.636 (p=0.001) and 0.8-1.0 for diagnosis of grade 2 varices (p<0.0001). CONCLUSIONS: Outpatient unsedated ultrathin endoscopy in patients with cirrhosis is accurate, safe and feasible. This integrative care model is convenient, particularly for regional communities, and is likely to result in significant cost savings associated with variceal surveillance.

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