Seroconversion After Coronavirus Disease 2019 Vaccination.

TO THE EDITOR:

We would like to comment on the article titled “Seroconversion After Coronavirus Disease 2019 Vaccination in Patients Awaiting Liver Transplantation: Fact or Fancy?” Calleri et al. concluded that “Our data from 89 patients awaiting LT suggest a high rate of immunization (94.4%) after a median time of 23 days from safe mRNA … monitored over time. ” Regarding patients waiting for liver transplantation (LT), the main underlying pathological condition is abnormal liver function. The degree of impaired liver function might be associated with immunogenicity after a vaccination. However, there are no data for coronavirus disease 2019 vaccination. The present report by Calleri et al. can confirm the usefulness of vaccination for patients waiting for LT. Indeed, the immunogenicity process related to messenger RNA is directly related to cellular immune responses, not the humoral immune response, which might be affected by impaired liver function. In addition, it is interesting to discuss the diagnostic accuracy of the Liaison (DiaSorin, Saluggia, Italy) SARS‐CoV‐2 TrimericS IgG assay. The lack of agreement between this assay and other widely used assays has been reported. Discordant results with a neutralization assay are also reported, and they might imply that the identified level of antibody by the LIAISON SARS‐CoV‐2 TrimericS IgG assay does not directly imply effective immunization or protection against disease.