In patients with COVID-19, preliminary data suggested that CLD of any etiology was associated with worse outcomes (
3,
4). The adverse effects related to COVID-19 vaccination are mostly mild and limited to injection site pain, fatigue, headache, myalgia, chills, and fever (
5,
6). However, there were insufficient data supporting the safety of vaccination. Rare patients of autoimmune hepatitis or autoimmune-like hepatitis were reported within days to weeks after receiving mRNA-based COVID-19 vaccines (
7,
8).
The safety of COVID-19 inactivated vaccine in patients with chronic HBV infection were also studied. The adverse effects were similar between patients with chronic HBV infection and healthy population (
9). No serious side effects were observed even in patients with compensated liver cirrhosis and the immune response was better in patients receiving antiviral therapy for chronic HBV infection (
10).
According to the AASLD 2018 guideline, patients with HBV infection receiving chemotherapy or immunosuppressive therapy should be administered antiviral therapy before and at least six to twelve months (at least twelve months for anti-CD20 therapy) after completing chemotherapy or immunosuppression (
11). Tenofovir alafenamide (vemlidy) was discontinued six months after completion of chemotherapy with bendamustine plus rituximab treatment with undetectable HBV viral load in Patient 3. We discontinued Tenofovir alafenamide (vemlidy) after six months but within twelve months after completing rituximab, which could be criticized. However, the HBV viral load was undetectable at that time, and the risk of reactivation of HBV infection should therefore be low.
COVID-19-related HBV reactivation has been reported in some previous studies (
12-
14). SARS-CoV-2-induced extreme inflammatory response is one of the explanations, and the immunosuppressive treatment for COVID-19 may also contribute to it. Furthermore, co-infection of SARS-CoV-2 and HBV poses risk of greater liver injury. The potential factors include direct liver injury by SARS-CoV-2, hepatotoxic antiviral drugs during COVID-19 therapy, and immune-mediated inflammatory response post SARS-CoV-2 co-infection (
14). Hepatitis C virus (HCV) reactivation following mRNA-based Pfizer-BioNTech COVID-19 vaccine has also been reported (
15). Reactivation of HBV after mRNA-based or chimpanzee adenovirus-vectored COVID-19 vaccines was not previously reported. To the best of our knowledge, this is the first reported episode of ACLF due to HBV reactivation after COVID-19 vaccination. The mechanism behind this issue is unclear. One possible explanation is that COVID-19 vaccination influences the normal immune response to HBV and causes subsequent reactivation.
New virus variants keep coming out and extra doses of COVID-19 vaccine is considered in this setting. According to our findings, prophylactic antiviral therapy prior to vaccination for individuals with HBV infection should be considered.
In summary, we presented three patients with ACLF suspected due to HBV reactivation after COVID-19 vaccination. Two of them received urgent living donor liver transplantation, and one was not qualified for her old age (73 years old). The cause-and-effect relationship between COVID-19 vaccination and HBV infection flare was not established, and the mechanism remained unknown. In this regard, further studies are needed. Moreover, during the COVID-19 pandemic, prophylactic antiviral therapy for individuals with HBV infection prior to vaccination deserves attention.