Breakthrough Infections and Low Mortality Observed in Heart Transplant Recipients Infected with COVID-19 at UC San Diego

PURPOSE: Management of COVID-19 has evolved over the course of the pandemic, with new therapies contributing to a decline in mortality in the general population. Immunosuppressed heart transplant (HT) recipients are at high risk of infection, but questions remain regarding their optimal management as these patients were excluded from many clinical trials on COVID-19 therapeutics and vaccines. METHODS: Retrospective search of electronic health records identified 41 HT recipients who tested positive for SARS-CoV-2 from February 1, 2020-October 13, 2021. RESULTS: Among the 41 HT recipients infected with SARS-CoV-2, 15 (36%) were monitored as outpatient, and of these, 4 received casirivimab/imdevimab and 1 received oral steroid. No COVID-19 related deaths were observed in this group. The remaining 26 patients (64%) were admitted for pneumonia or hypoxia. Five required admission to the intensive care unit (ICU), of which 3 required intubation and pressor support and 2 died (7.7% in-hospital mortality, 4.9% overall mortality). Of those admitted, 15 were treated with remdesivir and 7 received steroids. After vaccines were available in January 2021, 10 patients developed breakthrough COVID-19 occurring 2 weeks after the second Pfizer dose (n=6) and second Moderna dose (n=4). 8 of these patients were admitted for pneumonia or hypoxia and treated with COVID-19 directed therapies (4 received remdesivir, 2 received dexamethasone, 3 received casirivimab/imdevimab). 2 patients were monitored as outpatient where they received casirivimab/imdevimab. There was no severe illness or deaths observed in vaccinated patients. CONCLUSION: We present 41 HT recipients at UCSD infected with COVID-19. By using outpatient isolation, monoclonal antibody infusions, and admission for treatment of hypoxic patients with remdesivir and steroid, we have demonstrated a lower mortality from COVID-19 compared to other studies on HT recipients. No mortality was observed in the breakthrough cases.