Longevity of seropositivity after anti SARS-CoV-2 vaccination in patients awaiting liver transplant

ABSTRACT

Introduction: Anti-SARS-CoV-2 vaccines demonstrated a high rate of success in preventing severe COVID-19 and decreasing infection rate. Few data are available in pre-liver transplant (LT) patients. IgG anti-Spike reflect humoral response to vaccination. Aims: We aimed to evaluate longevity of humoral response to mRNA vaccine in our pre-LT patients. Methods: From 01/2021 to 10/2021 we enrolled all pre-LT patients who completed anti-SARS-CoV-2 mRNA vaccination. Patients with previous COVID-19 received 1 vaccine dose within 6 months after infection. All the others received 2 doses. Patients were tested for IgG (LIAISON® SARS-CoV-2 TrimericS, positivity≥33.8 BAU/mL) 1 month post-vaccination and then every 2 months until LT. Results: During study period, 91 pre-LT patients completed anti-SARS-CoV-2 vaccination 80 patients received 2 doses, 11 patients 1 dose, as per protocol (94% Pfizer-BioNTech, 6% Moderna-COVID-19). 69% male, median age 56 years, BMI 25kg/m2, eGFR 95ml/min, MELD 12;43% HCC;6 patients on steroids for autoimmune cirrhosis. 23 days post-vaccination (T1), 86/91 (95%) seroconverted (median titer 1970 BAU/mL). During follow-up none of retested patients became IgG negative, however their titer progressively dropped 72 days post-vaccination (T2), 61/64 (95%) tested again IgG positive (median titer 1480);at T3 (113 days post-vaccination) 42/43 (98%) patients remained positive and their titer significantly decreased (779);23 pts were retested at T4 (140 days post-vaccination) and all of them remained IgG positive (median titer 320). (T1vsT2, p=0.22;T2vsT3 p<0.001;T3vsT4, p=0.02;T1vsT4, p=0.008). At the end of a median follow-up of 190 days from vaccination, none of the patients developed COVID-19. No serious adverse events were registered. Conclusions: In our 91 pre-LT patients, mRNA anti-SARS-CoV-2 vaccination elicited a high rate of seroconversion (95%) within 1 month. We observed a progressive significant decrease in IgG titer during a median follow-up of 190 days after vaccination. Nevertheless, none of our pre-LT patients developed COVID-19. [Formula presented]