New research indicates that the effectiveness of COVID-19 vaccines is diminished in patients who are taking immunosuppressive drugs and antiviral medications for hepatitis B following living-donor liver transplantation (LDLT). The study suggests that additional vaccine doses may be beneficial to boost antibody levels in this vulnerable patient population.
The study, led by Ryunjin Lee from the Asan Medical Institute of Convergence Science and Technology in South Korea, highlights differences in immune response dynamics between immunocompromised individuals on immunosuppressants and those with hepatitis B receiving antiviral drugs post-liver transplant. The findings revealed that vaccine efficacy was reduced in patients taking immunosuppressants compared to healthy controls, but was significantly lower in those concurrently taking immunosuppressants and antiviral agents.
Study Details and Findings
The study involved 87 liver transplant recipients who were administered immunosuppressive drugs after transplantation. Of these, 50 (57.5%) patients were taking both immunosuppressant and HBV antiviral drugs, while 37 (42.5%) received only immunosuppressants. The participants were vaccinated with either the BNT162b2 (Pfizer-BioNTech), mRNA-1273 (Moderna), or ChAdOx1 nCoV-19 (AstraZeneca) vaccine. A control group of 134 healthy healthcare workers was also included for comparison.
Researchers measured SARS-CoV-2 S1-specific antibody levels in patients' blood at six intervals to assess the vaccination effect. The results indicated that antibody levels were significantly increased in the healthy control group compared to the immunocompromised patients (P < .0001). Furthermore, antibody levels were significantly lower in immunocompromised patients receiving anti-HBV treatment than in the healthy control group (P < .0001).
Impact on Liver Function
The study also assessed vaccine-related liver damage by monitoring alanine aminotransferase (ALT), aspartate aminotransferase (AST), and total bilirubin levels. The investigators found no significant difference in liver function following liver transplantation before and after vaccination (P > .05), suggesting that COVID-19 vaccination does not lead to liver function deterioration in this population.
Breakthrough Infections
Notably, 23 patients experienced breakthrough infections, defined as SARS-CoV-2 infections in fully or partially vaccinated individuals who had not previously been infected with SARS-CoV-2. These infections occurred in 11 immunocompromised patients taking immunosuppressive drugs and 12 patients with hepatitis B.
Limitations and Future Directions
The authors acknowledged several limitations, including the small sample size, variations in the number of patients receiving each vaccine, age group bias due to governmental vaccine policies, the absence of data on specific COVID-19 variants, the lack of measurement of various T cell cytokines, and the lack of consideration for the different antibody responses observed between vaccines.
"In recipients of LDLT that are taking immunosuppressants, the efficacy of the COVID-19 vaccine was found to be lower compared to the healthy control group. However, HBV-positive individuals exhibited suboptimal responses, and our understanding of the mRNA vaccine’s effectiveness remains limited," the investigators concluded. They emphasized the need for further research to understand the influence of antiviral drugs on vaccine responses.
