Faculty Bibliography

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 1.40_1.77 , p = .006) but not more likely to develop high-titers (27% vs. 22%, wIRR = _0.44 0.92_1.93 , p = .8). 6 month post-D3, D3-JJ recipients were 1.41-fold more likely to seroconvert (88% vs. 59%, wIRR = _1.04 1.41_1.93 , p = .029) and 2.63-fold more likely to develop high-titers (59% vs. 21%, wIRR = _1.38 2.63_5.00 , 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.

UNLABELLED:Automation of deceased donor referrals with standardized clinical triggers allows organ procurement organizations to be rapidly aware of medically eligible potential donors without the need for manual reporting and subjective decision-making of otherwise very busy hospital staff. In October 2018, 3 Texas hospitals (pilot hospitals) began using an automated referral system; our goal was to evaluate the impact of this system on eligible donor referral. METHODS/UNASSIGNED:We studied ventilated referrals (n = 28 034) in a single organ procurement organization from January 2015 to March 2021. We estimated the change in referral rate in the 3 pilot hospitals due to the automated referral system using a difference-in-differences analysis with Poisson regression. RESULTS/UNASSIGNED:). CONCLUSIONS/UNASSIGNED:Following deployment of an automated referral system that did not require any actions by the referring hospital, referrals, authorizations, and organ donors increased substantially in the 3 pilot hospitals. Broader deployment of automated referral systems may lead to increases in the deceased donor pool.