ABSTRACT
Purpose: Organ transplant recipients (OTR) have worse outcomes from COVID-19 and weaker antibody responses to vaccination than do immunocompetent individuals. Data on clinical outcomes among OTR with breakthrough COVID-19 are urgently needed, given decreased vaccine efficacy against the B.1.617.2 (Delta) variant. We compared crude case fatality rates (CFR) between fully vaccinated and unvaccinated kidney transplant recipients (KTR) with COVID-19. Method(s): We identified KTR with COVID-19 at our institution between 3/1/20 and 11/17/21. Multi-organ transplant recipients, KTR who received additional ("booster") doses, and those with partial or unknown vaccination status were excluded due to small numbers. KTR were considered fully vaccinated 2 weeks after receiving either the second dose of an mRNA vaccine series (Moderna, Pfizer-BioNTech) or one dose of the Janssen viral vector vaccine. Demographics, clinical characteristics, and in-hospital or hospice care mortality were extracted from electronic medical records. Result(s): Among 109 KTR with COVID-19, 19 were fully vaccinated at symptom onset. Vaccinated KTR with COVID-19 were older (median: 63.5 vs. 57.5 years, P<0.05) and waited longer to seek care after symptom onset (median: 6 vs. 3 days, P<0.05). Comorbidities and time from transplant were comparable between the two groups. CFR was higher among vaccinated KTR (26% vs. 10%, HR 0.34, 95%CI 0.11-1, P=0.05;Fig. 1), although the difference was not significant after adjustment for age (aHR 0.53, 95%CI 0.17-1.61, P>0.1). All fatal breakthrough infections occurred when the Delta variant accounted for >98% of COVID-19 cases in our HHS region. Conclusion(s): Vaccinated OTR remain at high risk for fatal COVID-19. Younger OTR are likely more immunoprotected than older OTR, which-combined with the emergence of the Delta variant and easing of restrictions-may have contributed to the observed shift toward older age among KTR with breakthrough COVID-19 and the high resultant CFR. Vaccinated OTR may delay seeking care for breakthrough symptoms due to a false sense of security. Our findings highlight the importance of pretransplant vaccination, and, among OTR, the need for ongoing preventive measures (masks, social distancing, vaccination of close contacts, post-vaccine education) and additional vaccine doses. OTR should be linked to care immediately after exposure or onset of symptoms consistent with COVID-19, given the availability of anti-spike monoclonal antibodies for prevention or treatment. (Figure Presented).