28 Humoral response to SARS-CoV-2 vaccination among heart transplant recipients aged 18–70 years of age administered two doses of an adenoviral vector (ChAdOx1 nCoV-19) vaccine and a messenger RNA (BNT162b2) booster

28 Figure 1a) Frequency of a detectable antibody response after each vaccination for 80 heart transplant recipients, b) Interval change in anti-spike antibody titres between the 2nd ChAdOx1 nCoV-19 vaccine and the 3rd dose mRNA (BNT162b2) booster vaccine.[Figure omitted. See PDF]Conclusions/ImplicationsHeart transplant recipients who received 2 doses of the ChAdOx1 nCoV-19 viral vector vaccine and a mRNA booster vaccine failed to develop a detectable antibody response in 44% of cases. These findings highlight the importance of maintaining protective measures for transplant recipients, particularly those on more intensive immunosuppressive regimens, both at a personal and public health level, as well as investigating additional strategies to protect this vulnerable patient cohort.