Abstract
SARS-CoV-2 vaccination in solid organ transplant recipients is associated with suboptimal immune response and risk for breakthrough infection. It is not known whether they are at risk of severe post-vaccine breakthrough infections in the presence of SARSCoV-2 variant of concern. We describe a case series of four fully vaccinated solid organ transplant recipients who developed SARS-CoV-2 variants of concern breakthrough infections. Three patients received BNT162b2 mRNA (Pfizer-BioNTech) and one patient received ChAdOx1 (AZD12220) COVID-19 vaccines. The patients were infected with SARS-CoV-2 variants circulating in Saudi Arabia. Two patients were infected with Alpha variant and had severe pneumonia requiring intensive care admission and ventilatory support and subsequently died. The other two patients recovered; one patient was infected with Beta variant required low supplemental oxygen via nasal flow and the other patient was infected with Delta variant and required high supplemental oxygen nasal flow. Younger patients had a better outcome than older patients. Future large studies are required to confirm our observations and to compare the different vaccine efficacy among solid organ transplants in the era of SARS-CoV-2 variants of concern.