Seroconversion in liver and intestine transplant patients after one, two or three doses of adenoviral vector vaccines against SARS-CoV-2. Single center experience in Argentina

SILVINA, YANTORNO; RENATA, CURCIARELLO; GASTÓN, RIZZO; COMPAGNUCCI MALENA, FERREYRA; LORENA, TAU; LAURA, DELAPLACE; VALERIA, DESCALZI; GABRIEL, GONDOLESI; GUILLERMO, DOCENA; MARTIN, RUMBO; VIRGINIA GENTILINI, MARÍA

HUMAN IMMUNOLOGY

ELSEVIER SCIENCE INC

Año: 2024 vol. 85

0198-8859

Background: The capacity of different anti‐SARS‐CoV‐2 vaccines to elicit immune response is not equivalent inthe healthy population compared to chronically immunosuppressed patients. Most of the reports available toassess the effects of anti‐SARS‐CoV‐2 vaccines on solid organ transplant recipients (SOTR) were performedusing mRNA‐based vaccines.Objective: This study aims to assess the seroconversion rate in a cohort of liver and liver‐ intestinal transplantpatients after vaccination with the non‐replicative vector‐based vaccines after transplantation used in our country,Argentina (rAd26‐rAd5 (Sputnik V) and ChAdOx11 nCoV‐19 (AZD1222) (Astra Zeneca‐Oxford).Methods: One hundred and three (103) liver and liver‐intestinal transplant recipients were enrolled. Patientswith previous PCR‐confirmed COVID19 were excluded, therefore 77 were finally included for analysis; 75 wereliver transplant recipients, 1 was a combined liver‐intestine and 1 a multivisceral transplant. All received theirfirst vaccine dose between March and June 2021; 66,2% males, and the mean age was 56,3 years. All patientshave a post‐transplant follow up longer than 1 year (mean 6.6 years, median 5 years, range 1–23 years).Immune response after first, second and third doses were determined using three different spike (S)‐S commercialELISA kits and an in‐house made anti nucleocapsid‐protein (N) ELISA.Results: Following the three doses, 57.1 % (44/77) of the patients seroconverted, while 33/77 (42.9 %) did notpresent anti‐SARS‐CoV‐2 antibodies. The seroconversion rate was different for each dose. We found that 5/27(18.5 %) of transplant patients seroconverted after a single dose; 18/29 pts (62.0 %) had anti‐SARS‐Cov‐2 antibodiesafter the second doses; and 18/21 pts (85.7 %) reached the seroconversion after the third doses. Theproportion of seroconversion was significantly increased in the second doses regardless the response observedafter the first doses (p = 0.012, Fisher’s exact test), particularly when two doses of ChAdOx11 vaccine wasadministrated (p = 0.040, Chi‐square). However, the comparisons of seroconversion rate between SputnikV and ChAdOx11 vaccines showed no differences after the different vaccination doses. No significant statisticaldifference in patient´s gender, age, comorbidities, type of vaccine, post‐transplant, or maintenance immunosuppressivetherapy was found between responders and non‐responders.Conclusion: Despite having a lower seroconversion rate compared to the general population, viral‐vector vaccinesbenefit SOTR patients increasing the seroconversion rate using at least two doses of vaccine. These results support the concept of developing tailor‐made vaccination guidelines for this specific population. This analysisprovides further support to safety and efficacy of viral‐vector vaccines in liver and liver‐intestine transplantpatients.