SARS-CoV-2 vaccine antibody response and breakthrough infections in transplant recipients.

Rates and modulators of SARS-CoV-2 vaccine nonresponse and breakthrough infections remain unclear in serially vaccinated transplant recipients. In a prospective, mono-centric, observational study, 1878 adult solid organ and hematopoietic cell transplant recipients, with prior SARS-CoV-2 vaccination, were included between March 2021 and February 2022. SARS-CoV-2 anti-spike IgG antibodies were measured at inclusion and details on SARS-CoV-2 vaccine doses and infection were collected. No life-threatening adverse events were reported after a total of 4039 vaccine doses. In transplant recipients without prior SARS-CoV-2 infection (n = 1636), antibody response rates ranged widely, from 47% in lung transplant to 90% in liver transplant and 91% in hematopoietic cell transplant recipients after third vaccine dose. Antibody positivity rate and levels increased after each vaccine dose in all types of transplant recipients. In multivariable analysis, older age, chronic kidney disease and daily dose of mycophenolate and corticosteroids were negatively associated with antibody response rate. Overall rate of breakthrough infections was 25.2% and mainly (90.2%) occurred after third and fourth vaccine dose. Lung transplant recipients had the highest rates of severe breakthrough infection (10.5%) and death (2.5%). In multivariable analysis, older age, daily dose of mycophenolate and corticosteroids were associated with severe breakthrough infection. Transplant recipients with infection before first vaccine dose (n = 160) had higher antibody response rates and levels after each vaccine dose, and a significantly lower overall rate of breakthrough infections compared to those without prior infection. Antibody response after SARS-CoV-2 vaccination and rate of severe breakthrough infections vary largely between different transplant types and are modulated by specific risk factors. The observed heterogeneity supports a tailored approach against COVID-19 in transplant recipients.

Transplantation of donor hearts after circulatory death using normothermic regional perfusion and cold storage preservation.

OBJECTIVES: Hearts donated after circulatory determination of death are usually preserved with normothermic machine perfusion prior to transplantation. This type of preservation is costly, requires bench time adding to warm ischaemia, and does not provide a reliable evaluation of the unloaded donor heart. We report on 4 successful donation after circulatory death (category III) hearts transplanted after thoraco-abdominal normothermic regional perfusion (NRP) and static cold storage. METHODS: After life sustaining therapy was withdrawn and death was declared, perfusion to thoraco-abdominal organs was restored using extracorporeal circulation via cannulas in the femoral artery and vein and clamping of supra-aortic vessels. After weaning from extracorporeal circulation, cardiac function was assessed. Once approved, the heart was retrieved and stored using classic static cold storage. Data are expressed as median [min-max]. RESULTS: Donor and recipient ages were 44 years [12-60] (n = 4) and 53 years [14-64] (n = 4), respectively. Time from the withdrawal of life sustaining therapy to start of NRP was 22 min [18-31]. Cold storage time was 72 min [35-129]. Thirty-day survival was 100% with a left ventricle ejection fraction of 60% [50-60]. CONCLUSIONS: Donation after circulatory death heart transplantation using thoraco-abdominal NRP and subsequent cold storage preservation for up to 129 min was safe for 4 procedures and could be a way to expand the donor heart pool while avoiding costs of machine preservation.