Korean J Transplant.  2022 Nov;36(Supple 1):S220. 10.4285/ATW2022.F-3568.

Antibody production after SARS-CoV2 vaccination and COVID-19 incidence in liver transplant recipients

• Masano Y
• Ito T
• Aoki H
• Hirata M
• Okumura S
• Anazawa T
• Nagai K
• Hata K
• Hatano E

• KMID: 2535285
• DOI: http://doi.org/10.4285/ATW2022.F-3568

Abstract

Background
Organ transplant recipients are immunocompromised and at high risk for COVID-19. In the present study, we investigated the antibody production after SARS-CoV2 vaccination and COVID-19 incidence in liver transplant recipients.
Methods
Thirty patients who were vaccinated at least 6 months after liver transplantation were included. IgG antibodies against nucleocapsid protein and spike protein (N-IgG, S-IgG) were quantified. We also investigated immunosuppressive ther-apy, number of vaccinations, severity of COVID-19, and outcome of PCR test-positive liver transplant recipients after January 2020.
Results
One patient had a subclinical infection with positive N-IgG and S-IgG titers before vaccination. Three patients were infected after their vaccination started; S-IgG antibody titers were positive in 45% before the second vaccination, and in 80%, 90%, and 90% after 1, 3, and 6 months the second vaccination, respectively. Median antibody titers were 227, 381, and 208 U/mL at 1, 3, and 6 months after the second vaccination, respectively, and decreased after 6 months. 78,800, 12,000, and 14,800 U/ mL S-IgG in COVID-19 patients after twice vaccinations were significantly higher than vaccination, and the severity of COVID-19 was mild. Three patients were negative for S-IgG antibodies after vaccination and were treated with three immunosuppressive drugs. Of the 1,370 post-liver transplant patients under follow-up at our department, 12 had COVID-19 by the end of December 2021, all seven patients over the age of 60 had moderate or severe disease, and two of seven died.
Conclusions
Although the acquisition rate of antibody titers tended to decrease when three immunosuppressive drugs were used in combination, antibody titers could be maintained by twice vaccinations even in post-liver transplant recipients. Appropriate dose reduction of immunosuppressive agents and patient management are important in the treatment of COVID-19.