Antibody Responses to COVID-19 Vaccination in Left Ventricular Assist Devices

PURPOSE: Left ventricular assist device (LVAD) implantation is associated with immune dysregulation and common occurrence of major infections. Whether humoral responses to COVID-19 vaccination are protective and durable in LVAD patients is uncertain. METHODS: We conducted a prospective single-center cohort study in LVAD patients without prior COVID-19 infection, who received 2 doses of BNT162b2 (Pfizer) or mRNA-1273 (Moderna) or 1 dose of Ad26.COV2.S (J&J) COVID-19 vaccines. Serologic testing was performed at 3, 6, and 9 months after COVID-19 vaccination using the Roche Elecsys anti-SARS-CoV-2 spike enzyme immunoassay (range <0.4 to >2500 U/mL [positive ≥0.8]), which tests for antibodies against the spike protein's receptor-binding domain (RBD). RESULTS: In March 2021, 45 LVAD patients (80% HeartMate 3) were enrolled and 24 (53%) received Pfizer vaccines, 17 (38%) Moderna, and 4 (9%) J&J at a median duration of LVAD support of 34 months (1-114). Most were male (89%) and white non-Hispanic (71%) persons with median age 62 years (23-78); 26 (58%) had diabetes, 16 (36%) had chronic kidney disease (CKD), and 3 (7%) were on immunosuppressive medications. Median absolute lymphocyte count (ALC) at the time of their vaccine was 1.26 K/uL (0.54-3.41). All patients developed a detectable anti-RBD antibody after vaccination, which began to wane after 3 months. The median anti-RBD IgG titers were 1132 U/mL, 360 U/mL, and 286 U/mL at 3, 6, and 9 months, respectively, post-vaccination (Figure). Age > 60 years, ALC < 1.5 K/uL, and history of CKD were associated with lower median anti-RBD IgG titers at 3, 6, and 9 months. Moderna vaccine recipients had the highest and J&J the lowest anti-RBD IgG titers at 3-months. In the 9-month study period, there were no vaccine-related serious adverse events or breakthrough COVID-19 infections. CONCLUSION: LVAD patients exhibit a robust humoral response to COVID-19 vaccination without breakthrough infection. Further research to evaluate cellular responses to COVID-19 vaccination in LVAD patients is warranted.