To the editor:We appreciate the interest garnered by the article “Heterologous adenovirus‐vector/messenger RNA regimen is associated with improved severe acute respiratory syndrome coronavirus 2 humoral response in liver transplant recipients.” The comments by Dr. Sookaromdee and Dr. Wiwanitkit highlighted the importance of assessing prior severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection when testing antibody response to SARS‐CoV‐2 vaccination. This observation is relevant given that patients who recovered from corona virus disease 2019 (Covid‐19) present detectable prevaccination anti‐spike immunoglobulin G titers, even liver transplant recipients.[ 1 ] Moreover, after receiving a complete vaccination scheme, the antibody titer can significantly increase compared to patients naive for Covid‐19.[ 1 , 2 ] However, to avoid this bias and consequently misinterpret the effect of vaccination, in our study population, we excluded patients with prior infection confirmed by polymerase chain reaction. Likewise, as detailed in the methods section, before patients' inclusion, antibodies toward the nucleocapsid (N) protein were analyzed by chemiluminescence assay (ALINITY SARS‐COV‐2 IGG; Abbott) in a certified biochemistry testing laboratory to estimate past SARS‐CoV‐2 infection.
In summary, we are satisfied with these discussions and interactions, which enrich our study, and we trust that our results will be a key tool for both conventional clinical practices as well as future research.
CONFLICT OF INTEREST
Nothing to report.
Contributor Information
Manuel Mendizabal, Email: mmendiza@cas.austral.edu.ar.
Ezequiel Mauro, Email: ezequiel.mauro@icloud.com.
REFERENCES
- 1. Toniutto P, Falleti E, Cmet S, Cussigh A, Veneto L, Bitetto D, et al. Past COVID‐19 and immunosuppressive regimens affect the long‐term response to anti‐SARS‐CoV‐2 vaccination in liver transplant recipients. J Hepatol. 2022;77:152–62. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2. Schmidt T, Klemis V, Schub D, Schneitler S, Reichert MC, Wilkens H, et al. Cellular immunity predominates over humoral immunity after homologous and heterologous mRNA and vector‐based COVID‐19 vaccine regimens in solid organ transplant recipients. Am J Transplant. 2021;21:3990–4002. [DOI] [PMC free article] [PubMed] [Google Scholar]