COVID-19 vaccine immunogenicity among chronic liver disease patients and liver transplant recipients: A meta-analysis

Immunogenicity of COVID-19 vaccines in patients with cirrhosis: A meta-analysis

The immunogenicity of COVID-19 vaccines in patients with liver cirrhosis remains largely unknown. The purpose of this meta-analysis was to investigate the immunogenicity of COVID-19 vaccines in patients with cirrhosis and compare the humoral and cellular immune responses following complete COVID-19 vaccination between cirrhosis patients and healthy controls. A systematic literature search was conducted in PubMed, EMBASE, and Web of Science from 1 January 2020 to 22 August 2023. Sixteen studies with 2127 cirrhosis patients were included. The pooled seroconversion rate in patients with cirrhosis following complete COVID-19 vaccination was 92.4% (95% CI, 86.2%-96%, I2 = 90%) with significant between-study heterogeneity. Moreover, COVID-19 vaccination elicited a higher humoral immune response in patients of compensated cirrhosis as compared with decompensated cirrhosis (RR = 1.069, 95% CI, 1.011-1.131, I2 = 17%, p = .019). Additionally, 10 studies were included for comparison analysis of seroconversion rate between cirrhosis patients and healthy controls. The results showed that the seroconversion rate in patients with cirrhosis was slightly lower compared with healthy controls (RR = 0.972, 95% CI, 0.955-0.989, I2 = 66%, p = .001). Meanwhile, the pooled RR of cellular immune response rate for cirrhosis patients vs. healthy controls was 0.678 (95% CI, 0.563-0.817, I2 = 0, p < .0001). Our meta-analysis demonstrated that COVID-19 vaccination elicited diminished humoral and cellular immune responses in patients of cirrhosis. Patients with cirrhosis particularly decompensated cirrhosis who have completed full-doses of COVID-19 vaccination should receive continuous attention and preemptive measures.

Clinical application of COVID-19 vaccine in liver transplant recipients

BACKGROUND

Solid organ transplant (SOT) activities, such as liver transplant, have been greatly influenced by the pandemic of coronavirus disease 2019 (COVID-19), a disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Immunosuppressed individuals of liver transplant recipients (LTRs) tend to have a high risk of COVID-19 infection and related complications. Therefore, COVID-19 vaccination has been recommended to be administered as early as possible in LTRs.

DATA SOURCES

The keywords "liver transplant", "SARS-CoV-2", and "vaccine" were used to retrieve articles published in PubMed.

RESULTS

The antibody response following the 1st and 2nd doses of vaccination was disappointingly low, and the immune responses among LTRs remarkably improved after the 3rd or 4th dose of vaccination. Although the 3rd or 4th dose of COVID-19 vaccine increased the antibody titer, a proportion of patients remained unresponsive. Furthermore, recent studies showed that SARS-CoV-2 vaccine could trigger adverse events in LTRs, including allograft rejection and liver injury.

CONCLUSIONS

This review provides the recently reported data on the antibody response of LTRs following various doses of vaccine, risk factors for poor serological response and adverse events after vaccination.

Proton pump inhibitors associated with severe COVID-19 among two-dose but not three-dose vaccine recipients

BACKGROUND AND AIM

Proton pump inhibitors (PPIs) may increase the risk of COVID-19 among non-vaccinated subjects via various mechanisms, including gut dysbiosis. We aimed to investigate whether PPIs also affect the clinical outcomes of COVID-19 among vaccine recipients.

METHODS

This was a territory-wide cohort study of 3 272 286 vaccine recipients (aged ≥ 18 years) of ≥ 2 doses of either BNT162b2 or CoronaVac. Exclusion criteria included prior gastrointestinal surgery, immunocompromised status, and prior COVID-19. The primary outcome was COVID-19, and secondary outcomes included COVID-19-related hospitalization and severe infection (composite of intensive care unit admission, ventilatory support, and/or death). Covariates include age, sex, the Charlson Comorbidity Index, comorbidities, and concomitant medication use. Subjects were followed from index date (first dose of vaccination) until outcome occurrence, death, additional dose of vaccination, or March 31, 2022. Exposure was pre-vaccination PPI use (any prescription within 90 days before the index date). Propensity score (PS) matching and a Poisson regression model were used to estimate the adjusted incidence rate ratio (aIRR) of outcomes with PPI use.

RESULTS

Among 439 154 PS-matched two-dose vaccine recipients (mean age: 65.3 years; male: 45.7%) with a median follow-up of 6.8 months (interquartile range: 2.6-7.9), PPI exposure was associated with a higher risk of COVID-19 (aIRR: 1.08; 95% confidence interval [95% CI]: 1.05-1.10), hospitalization (aIRR: 1.20; 95% CI: 1.08-1.33), and severe infection (aIRR: 1.57; 95% CI: 1.24-1.98). Among 188 360 PS-matched three-dose vaccine recipients (mean age: 62.5 years; male: 49.0%; median follow-up: 9.1 months [interquartile range: 8.0-10.9]), PPIs were associated with higher infection risk (aIRR: 1.11; 95% CI: 1.08-1.15) but not other outcomes.

CONCLUSIONS

Although PPI use was associated with a higher COVID-19 risk, severe infection was limited to two-dose but not three-dose vaccine recipients.

Third vaccine boosters and anti-S-IgG levels: A comparison of homologous and heterologous responses and poor immunogenicity in hepatocellular carcinoma

The immune response of patients with chronic liver disease tends to be lower after receiving their second coronavirus disease 2019 (COVID-19) vaccine dose, but the effect of a third vaccine dose on their immune response is currently unknown. We recruited 722 patients without previous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection from three hospitals. The patients received homologous (MMM) and heterologous (AZAZBNT, AZAZM) boosters, where AZ, BNT, and M denoted the AZD1222, BNT162b2, and mRNA-1273 vaccines, respectively. Serum IgG spike antibody levels were measured at a mean 1.5 ± 0.7 (visit 1) and 5.0 ± 0.5 (visit 2) months after the third vaccine booster. A threshold of 4160 AU/mL was considered significant antibody activity. In both visits, the patients who received the MMM booster had higher anti-S-IgG levels than those who received the AZAZBNT and AZAZM boosters. Patients with active hepatocellular carcinoma (HCC) had lower anti-S-IgG levels than the control group (761.6 vs. 1498.2 BAU/mL; p = 0.019) at visit 1. The anti-S-IgG levels decreased significantly at visit 2. The patients with significant antibody activity had a lower rate of liver cirrhosis with decompensation (0.7% decompensation vs. 8.0% non-decompensation and 91.3% non-liver cirrhosis, p = 0.015), and active HCC (1.5% active HCC vs. 3.7% non-active HCC and 94.7% non-HCC, p < 0.001). Receiving the MMM booster regimen (OR = 10.67, 95% CI 5.20-21.91, p < 0.001) increased the odds of having significant antibody activity compared with the AZAZBNT booster regimen. Patients with active HCC had a reduced immune response to the third COVID-19 vaccine booster. These findings underscore the importance of booster vaccinations, especially in immunocompromised patients, with superior efficacy observed with the homologous mRNA-1273 regimen.

Clinical characteristics and outcomes of liver transplant recipients infected by Omicron during the opening up of the dynamic zero-coronavirus disease policy in China: A prospective, observational study

We analyzed the characteristics, risk factors, outcomes, and post-coronavirus disease 2019 (COVID-19) symptoms in liver transplant recipients in China's late 2022 COVID-19 wave. Recipients with COVID-19 were enrolled from December 1, 2022, to January 31, 2023, and followed up until May 31, 2023. Baseline and characteristic data were collected. A total of 930 recipients were included, with a vaccination rate (non-mRNA) of 40.0%. Among 726 (78.1%) recipients with COVID-19, 641 (88.3%) patients were treated at home, 81 (11.2%) patients required hospitalization in general wards, 4 (0.6%) patients required intensive care, and 1 (0.1%) patient died because of COVID-19. Severe acute respiratory syndrome coronavirus 2 infection was related to close contact with confirmed cases (P < .001) and the condition of end-stage kidney disease (P < .046). Older age, male sex, less vaccination, and hypertension were independent risk factors for hospitalization. Fatigue (36.9%) was the most common symptom post-COVID-19, followed by memory loss (35.7%) and sleep disturbance (23.9%). Two doses of vaccines had a protective effect against these post-COVID-19 symptoms (P < .05). During this Omicron outbreak, liver transplant recipients were susceptible to COVID-19, with frequent hospitalization but low mortality. Two doses of non-mRNA COVID-19 vaccines could protect against liver transplant recipient hospitalization and post-COVID-19 symptoms.

Association between Gut Microbiota Composition and Long-Term Vaccine Immunogenicity following Three Doses of CoronaVac

BACKGROUND

Neutralizing antibody level wanes with time after COVID-19 vaccination. We aimed to study the relationship between baseline gut microbiota and immunogenicity after three doses of CoronaVac.

METHODS

This was a prospective cohort study recruiting three-dose CoronaVac recipients from two centers in Hong Kong. Blood samples were collected at baseline and one year post-first dose for virus microneutralization (vMN) assays to determine neutralization titers. The primary outcome was high immune response (defined as with vMN titer ≥ 40). Shotgun DNA metagenomic sequencing of baseline fecal samples identified potential bacterial species and metabolic pathways using Linear Discriminant Analysis Effect Size (LEfSe) analysis. Univariate and multivariable logistic regression models were used to identify high response predictors.

RESULTS

In total, 36 subjects were recruited (median age: 52.7 years [IQR: 47.9-56.4]; male: 14 [38.9%]), and 18 had low immune response at one year post-first dose vaccination. Eubacterium rectale (log10LDA score = 4.15, p = 0.001; relative abundance of 1.4% vs. 0, p = 0.002), Collinsella aerofaciens (log10LDA score = 3.31, p = 0.037; 0.39% vs. 0.18%, p = 0.038), and Streptococcus salivarius (log10LDA score = 2.79, p = 0.021; 0.05% vs. 0.02%, p = 0.022) were enriched in low responders. The aOR of high immune response with E. rectale, C. aerofaciens, and S. salivarius was 0.03 (95% CI: 9.56 × 10-4-0.32), 0.03 (95% CI: 4.47 × 10-4-0.59), and 10.19 (95% CI: 0.81-323.88), respectively. S. salivarius had a positive correlation with pathways enriched in high responders like incomplete reductive TCA cycle (log10LDA score = 2.23). C. aerofaciens similarly correlated with amino acid biosynthesis-related pathways. These pathways all showed anti-inflammation functions.

CONCLUSION

E. rectale,C. aerofaciens, and S. salivarius correlated with poorer long-term immunogenicity following three doses of CoronaVac.

[Clinical courses and costs for hospitalizations of potentially immunocompromised COVID-19 patients in Germany]

BACKGROUND

 Patients at increased risk of inadequate immune response to COVID-19 vaccinations due to their underlying disease or therapy are potentially vulnerable to severe COVID-19 courses. The aim is to assess the population size, clinical courses and hospitalization costs of these patients in Germany.

METHODS

 This retrospective cohort study is based on extrapolations of a representative sample of statutory health insurance (SHI) claims data from 2020. Clinical COVID-19 courses, hospitalization costs and durations are compared between the insured group at increased risk for inadequate immune response to COVID-19 vaccinations (risk group) and the insured group without this risk.

RESULTS

 There are approximately 1.82 million SHI-insured individuals in the risk group, of whom an estimated 240 000 insured individuals do not develop a humoral immune response after 3 COVID-19 vaccinations. The risk group shows higher proportions with COVID-19 (relative risk [RR] 1.21; 95 % confidence interval [95 % CI] 1.20-1.23), hospitalizations for COVID-19 (RR 3.40; 95 % CI 3.33-3.48), hospitalizations for COVID-19 with intensive care treatment (RR 1.36; 95 % CI 1.30-1.42), and mortality (RR 5.14; 95 % CI 4.97-5.33) compared with the group without risk. In addition, hospitalizations in the risk group are on average 18 % longer (15.36 days vs. 13.00 days) and 19 % more expensive (12 371 € vs. 10 410 €). Expected hospitalization costs in the risk group are four times greater than in the group without risk (4115 € vs. 1017 €).

CONCLUSIONS

 The risk group is vulnerable to COVID-19 and requires additional resources in the German hospital sector. This results in a need for further protective measures. Further studies are needed to evaluate the impact of different viral variants, active and passive immunizations, and therapies on clinical COVID-19 courses and their costs.

Advancements in Vaccine Strategies for Chronic Liver Disease Patients: Navigating Post-COVID Challenges and Opportunities

This review addresses the vital role of vaccinations in managing patients with chronic liver disease (CLD), especially in the context of the post-COVID-19 landscape. The pandemic has highlighted the unique vulnerabilities of CLD patients, including those awaiting liver transplantation and post-transplant individuals, who face heightened risks of infection due to compromised immune responses. Recent advancements in vaccine technology, such as mRNA platforms, novel adjuvants, and advanced delivery systems, have significantly accelerated vaccine development, enhancing both speed and efficacy. Moreover, the emergence of personalized vaccines, tailored to everyone's unique immunological profile, presents new opportunities, particularly for those with chronic conditions. This review synthesizes the current state of evidence regarding vaccine recommendations for CLD patients, focusing on their response to vaccinations and proposing effective strategies to protect this vulnerable group from vaccine-preventable diseases. It also explores the challenges in implementing these strategies and considers the impact of emerging vaccine delivery systems on improving outcomes for CLD patients. The paper aims to provide nuanced guidance on vaccination in the rapidly evolving healthcare landscape, addressing both technological innovations and comprehensive patient care strategies.

Ursodeoxycholic acid does not affect the clinical outcome of SARS-CoV-2 infection: A retrospective study of propensity score-matched cohorts

BACKGROUND

Ursodeoxycholic acid (UDCA) has been recently proposed as a modulator of angiotensin-converting enzyme 2 (ACE2) receptor expression, with potential effects on COVID-19.

AIM AND STUDY DESIGN

We retrospectively evaluated the clinical course and outcome of subjects taking UDCA admitted to the hospital for COVID-19 compared with matched infected subjects. Differences regarding the severity and outcome of the disease between treated and non-treated subjects were assessed. The Kaplan-Meier survival analysis and log-rank test were used to evaluate the effect of UDCA on all-cause intra-hospital mortality.

RESULTS

Among 6444 subjects with confirmed COVID-19 admitted to the emergency department (ED) from 1 March 2020 to 31 December 2022, 109 subjects were taking UDCA. After matching 629 subjects were included in the study: 521 in the no UDCA group and 108 in the UDCA group. In our matched cohort, 144 subjects (22.9%) died, 118 (22.6%) in the no-UDCA group and 26 (24.1%) in the UDCA group. The Kaplan-Meier analysis showed no significant difference in survival between groups. In univariate regression analysis, the presence of pneumonia, National Early Warning Score (NEWS) score, and Charlson Comorbidity Index (CCI) were significant independent predictors of death. At multivariate Cox regression analysis, age, NEWS, pneumonia and CCI index were confirmed significant independent predictors of death. UDCA treatment was not a predictor of survival both in univariate and multivariate regressions.

CONCLUSIONS

UDCA treatment does not appear to have significant effects on the outcome of COVID-19. Specially designed prospective studies are needed to evaluate efficacy in preventing infection and severe disease.

Impact of SARS-CoV-2 Infection on Humoral and Cellular Immunity in a Cohort of Vaccinated Solid Organ Transplant Recipients

The aim of the present study was to determine humoral and T-cell responses after four doses of mRNA-1273 vaccine in solid organ transplant (SOT) recipients, and to study predictors of immunogenicity, including the role of previous SARS-CoV-2 infection in immunity. Secondarily, safety was also assessed. Liver, heart, and kidney transplant recipients eligible for SARS-CoV-2 vaccination from three different institutions in Barcelona, Spain were included. IgM/IgG antibodies and T cell ELISpot against the S protein four weeks after receiving four consecutive booster doses of the vaccine were analyzed. One hundred and forty-three SOT recipients were included (41% liver, 38% heart, and 21% kidney). The median time from transplantation to vaccination was 6.6 years (SD 7.4). In total, 93% of the patients developed SARS-CoV-2 IgM/IgG antibodies and 94% S-ELISpot positivity. In total, 97% of recipients developed either humoral or cellular response (100% of liver recipients, 95% of heart recipients, and 88% of kidney recipients). Hypogammaglobulinemia was associated with the absence of SARS-CoV-2 IgG/IgM antibodies and S-ELISpot reactivity after vaccination, whereas past symptomatic SARS-CoV-2 infection was associated with SARS-CoV-2 IgG/IgM antibodies and S-ELISpot reactivity. Local and systemic side effects were generally mild or moderate, and no recipients experienced the development of de novo DSA or graft dysfunction following vaccination.

Carvedilol Versus Other Nonselective Beta Blockers for Variceal Bleeding Prophylaxis and Death: A Network Meta-analysis

Background and Aims

We aimed to perform a network meta-analysis (NWM) to examine comparative effectiveness of non-selective beta blockers (NSBBs) on prophylaxis of gastroesophageal variceal bleeding (GVB) and mortality benefit.

Methods

MEDLINE (OVID) and EMBASE databases were searched for eligible randomized clinical trials (RCTs) from inception to July 3, 2021. Outcomes of interest included primary/secondary prophylaxis of GVB, failure to achieve hepatic venous pressure gradient (HVPG) decremental response, liver-related and all-cause mortality. A Bayesian NWM was performed to derive relative risk (RR) with 95% credible intervals (CrIs). The ranking probability of each NSBB was assessed by surface under cumulative ranking curve (SUCRA).

Results

Thirty-three RCTs including 3,188 cirrhosis patients with gastroesophageal varices were included. Compared with placebo, nadolol ranked first for reducing variceal bleeding [RR:0.25, (95% CrI:0.11-0.51); SUCRA:0.898], followed by carvedilol [RR:0.33, (95% CrI: 0.11-0.88); SUCRA:0.692] and propranolol [RR:0.52, (95% CrI:0.37-0.75); SUCRA:0.405]. Carvedilol was more effective than propranolol in achieving HVPG decremental response [RR:0.43, (95% CrI: 0.26-0.69)]. Carvedilol ranked first for reducing all-cause mortality [RR: 0.32, (95% CrI:0.17-0.57); SUCRA:0.963), followed by nadolol [RR:0.48, (95% CI:0.29-0.77); SUCRA:0.688], and propranolol [RR:0.77, (95% CI:0.58-1.02); SUCRA: 0.337]. Similar findings were observed for liver-related mortality. Carvedilol ranked the safest. The RR of adverse events was 4.38, (95% CrI:0.33-161.4); SUCRA:0.530, followed by propranolol [RR: 7.54, (95% CrI:1.90-47.89); SUCRA:0.360], and nadolol [RR: 18.24, (95% CrI:91.51-390.90); SUCRA:0.158].

Conclusions

Carvedilol is the preferred NSBB with better survival benefit and lower occurrence of adverse events among patients with gastroesophageal varices.

Factors influencing immunogenicity and safety of SARS-CoV-2 vaccine in liver transplantation recipients: a systematic review and meta-analysis

Background

This review summarizes the factors influencing the efficacy and safety of the COVID-19 vaccine in LTR through meta-analysis, hoping to provide strategies for vaccine use.

Methods

Electronic databases were screened for studies on mRNA vaccines in LTR. The primary outcome was the pooled seroconversion rate, and the secondary outcome was the incidence of adverse events+breakthrough infections. Subgroup analyses were made based on BMI, associated comorbidities, presence of baseline leukopenia, time since transplant, and drugs used.

Result

In total, 31 articles got included. The pooled seroconversion rate after at least two doses of SARS-CoV-2 vaccination was 72% (95% CI [0.52-0.91). With significant heterogeneity among studies I2 = 99.9%, the seroconversion rate was about 72% (95%CI [0.66-0.75]), from the studies reporting two doses of vaccine slightly higher around 75%(95%CI [0.29-1.22]) from studies reporting three doses. The pooled seroconversion rate within the lower to normal BMI group was 74% (95% CI [0.22-1.27], Pi=0.005) against 67% (95% CI [0.52-0.81], Pi=0.000) in the high BMI group. The pooled seroconversion rate in the ''positive leukopenia'' group was the lowest, 59%. Leukopenia could influence the vaccine seroconversion rate in LTR. From the time since transplant analysis after setting seven years as cut off point, the pooled seroconversion rate after at least two doses of COVID-19 vaccination was 53% (95% CI [0.18-0.83], P=0.003, I2 = 99.6%) in <7years group and 83% (95% CI [0.76-0.90], P=0.000 I2 = 95.7%) in > 7years group. The only time since transplantation had reached statistical significance to be considered a risk factor predictor of poor serological response (OR=1.27 95%CI [1.03-1.55], P=0.024). The breakthrough infection rate after vaccination was very low2% (95% CI 0.01-0.03, I2 = 63.0%), and the overall incidence of adverse events, which included mainly pain at the injection site and fatigue, was 18% (95%CI [0.11-0.25], I2 = 98.6%, Pi=0.000).

Conclusion

The seroconversion rate in LTR vaccinated with at least two doses of mRNA COVID-19 vaccine could be significantly affected by the vaccine type, immunosuppressant used, BMI, leukopenia, associated comorbidities, and time since transplantation. Nevertheless, booster doses are still recommended for LTR.

Metabolic Associated Fatty Liver Disease (MAFLD) and COVID-19 Infection: An Independent Predictor of Poor Disease Outcome?

Background and Objectives: Early reports on COVID-19 infection suggested that the SARS-CoV-2 virus solely attacks respiratory tract cells. As the pandemic spread, it became clear that the infection is multiorganic. Metabolic associated fatty liver disease (MAFLD) is a chronic liver disease strongly associated with insulin resistance and diabetes. The aim of this study was to assess a possible interplay between MAFLD and COVID-19 infection and its implication in COVID-19 outcome. Materials and Methods: A retrospective observational study, including 130 COVID-19 positive patients was conducted. MAFLD diagnosis was made based on the International Consensus criteria. Patients were divided into two groups, group A (MAFLD) and group B (nonMAFLD). Anthropometric and laboratory analysis were obtained. COVID-19 severity was assessed using the NEWS2 score. Disease outcome was threefold and regarded as discharged, patients who required mechanical ventilation (MV), and deceased patients. Results: MAFLD prevalence was 42%, 67% of patients were discharged, and 19% needed MV. Mortality rate was 14%. MAFLD patients were significantly younger (p < 0.001), and had higher body mass index (p < 0.05), respiratory rate (p < 0.05) and systolic blood pressure (p < 0.05) than nonMAFLD patients. Regarding metabolic syndrome and inflammatory markers: group A had significantly higher glycemia at admission (p = 0.008), lower HDL-c (p < 0.01), higher triglycerides (p < 0.01), CRP (p < 0.001), IL-6 (p < 0.05) and ferritin (p < 0.05) than group B. MAFLD was associated with more prevalent type 2 diabetes (p = 0.035) and hypertension (p < 0.05). MAFLD patients had a more severe disease course (NEWS2 score, 6.5 ± 0.5 vs. 3 ± 1.0, p < 0.05). MAFLD presence was associated with lower patient discharge (p < 0.01) and increased need for MV (p = 0.024). Multiple regression analysis showed that BMI (p = 0.045), IL-6 (p = 0.03), and MAFLD (p < 0.05) are significant independent risk factors for a poor COVID-19 outcome. Conclusions: The prevalence of MAFLD is relatively high. MAFLD patients had a more severe COVID-19 clinical course and worse disease outcome. Our results imply that early patient stratification and risk assessment are mandatory in order to avoid poor outcomes.

Antibiotic Use Prior to COVID-19 Vaccine Is Associated with Higher Risk of COVID-19 and Adverse Outcomes: A Propensity-Scored Matched Territory-Wide Cohort

Background: Antibiotics may increase the risk of COVID-19 among non-vaccinated subjects via probable gut dysbiosis. We aimed to investigate whether antibiotics also affect the clinical outcomes of COVID-19 vaccine recipients. Methods: This was a territory-wide cohort study of 3,821,302 COVID-19 vaccine recipients (aged ≥ 18 years) with ≥2 doses of either BNT162b2 or CoronaVac. Exclusion criteria included prior COVID-19, prior gastrointestinal surgery, and immunocompromised status. The primary outcome was COVID-19 infection and secondary outcomes included COVID-19-related hospitalization and severe infection (composite of intensive care unit admission, ventilatory support, and/or death). Exposure was pre-vaccination antibiotic use (within 180 days of first vaccine dose). Covariates included age, sex, Charlson Comorbidity Index, and concomitant medication use. Subjects were followed from the index date (first dose vaccination) until outcome occurrence, death, an additional dose of vaccination, or 15 November 2022. Propensity score (PS) matching and a Poisson regression model were used to estimate the adjusted incidence rate ratio (aIRR) of outcomes with antibiotic use. Results: Among 342,338 PS matched three-dose vaccine recipients (mean age: 57.4 years; male: 45.1%) with a median follow-up of 13.6 months (IQR: 9.2-16.3), antibiotics were associated with a higher risk of COVID-19 infection (aIRR: 1.16;95% CI: 1.14-1.19), hospitalization (aIRR: 1.75;95% CI: 1.65-1.86), and severe infection (aIRR: 1.60; 95% CI: 1.21-2.11). Notably, antibiotic use was associated with a higher risk of severe infection and death among CoronaVac recipients (aIRR: 1.62 95% CI: 1.18-2.22 and aIRR: 2.70, 95% CI: 1.54-4.73 for the two secondary outcomes, respectively), but not BNT162b2 recipients. Conclusions: Pre-vaccination use of antibiotics was associated with a higher risk of COVID-19 infection, hospitalization, and severe disease outcomes.

Susceptibility to SARS-CoV-2 Infection and Immune Responses to COVID-19 Vaccination Among Recipients of Solid Organ Transplants

Solid organ transplant recipients (SOTRs) are at high risk for infections including SARS-CoV-2, primarily due to use of immunosuppressive therapies that prevent organ rejection. Furthermore, these immunosuppressants are typically associated with suboptimal responses to vaccination. While COVID-19 vaccines have reduced the risk of COVID-19-related morbidity and mortality in SOTRs, breakthrough infection rates and death remain higher in this population compared with immunocompetent individuals. Approaches to enhancing response in SOTRs, such as through administration of additional doses and heterologous vaccination, have resulted in increased seroresponse and antibody levels. In this article, safety and immunogenicity of mRNA COVID-19 vaccines in SOTRs are explored by dose. Key considerations for clinical practice and the current vaccine recommendations for SOTRs are discussed within the context of the dynamic COVID-19 vaccination guideline landscape. A thorough understanding of these topics is essential for determining public health and vaccination strategies to help protect immunocompromised populations, including SOTRs.

COVID-19 and Liver Disease: An Evolving Landscape

The COVID-19 pandemic has resulted in significant worldwide morbidity and mortality. In this review, we examine the intricate relationships between COVID-19 and liver diseases. While respiratory manifestations of COVID-19 are well known, its impact and consequences in patients with liver diseases remain an area of ongoing investigation. COVID-19 can induce liver injury through various mechanisms and is associated with higher mortality in individuals with preexisting chronic liver disease. Mortality increases with the severity of chronic liver disease and the level of care required. The outcomes in patients with autoimmune hepatitis remain unclear, whereas liver transplant recipients are more likely to experience symptomatic COVID-19 but have comparable outcomes to the general population. Despite suboptimal immunological response, COVID-19 vaccinations are safe and effective in liver disease, although cases of autoimmune hepatitis-like syndrome have been reported. In conclusion, COVID-19 has significant implications in liver diseases; early recognition and treatments are important for improving patient outcomes.

Research landscape on COVID-19 and liver dysfunction: A bibliometric analysis

BACKGROUND

The global spread of severe acute respiratory syndrome coronavirus 2, responsible for coronavirus disease 2019 (COVID-19), poses a significant risk to public health. Beyond the respiratory issues initially associated with the condition, severe cases of COVID-19 can also lead to complications in other organs, including the liver. Patients with severe COVID-19 may exhibit various clinical signs of liver dysfunction, ranging from minor elevations in liver enzymes without symptoms to more serious cases of impaired liver function. Liver damage is more commonly observed in patients with severe or critical forms of the disease.

AIM

To present the research landscape on COVID-19 and liver dysfunction while also offering valuable insights into the prominent areas of interest within this particular domain.

METHODS

On 18 February 2023, Scopus was utilised to conduct a comprehensive exploration of the relationship between COVID-19 and the liver dysfunction. The investigation encompassed the period from 1 January 2020 to 31 December 2022. Primary sources were meticulously examined and organised in a Microsoft Excel 2013 spreadsheet, categorised by journal, institution, funding agency, country and citation type. VOSviewer version 1.6.18 was employed to explore the prominent topics and knowledge network related to the subject.

RESULTS

There were 2336 publications on COVID-19 and liver dysfunction analysed in this study, of which 558 were published in 2020, 891 in 2021 and 887 in 2022. Researchers from 111 different countries participated in the retrieved documents. The United States contributed the most studies, with 497 documents, representing 21.28% of the total, followed by China with 393 documents (16.82%) and Italy with 255 documents (10.92%). In the context of research related to COVID-19 and the liver, co-occurrence analysis identified three distinct clusters of topics: (1) ‘COVID-19 vaccines in liver transplant recipients’; (2) ‘liver function tests as a predictor of the severity and clinical outcomes in hospitalised patients’; and (3) ‘care of patients with liver disease during the COVID-19 pandemic’.

CONCLUSION

This bibliometric study provides a comprehensive overview of liver-related publications in COVID-19 research over the past 3 years. This study highlights the significant contributions of high-income nations, particularly the United States, China, and Italy, to the production of liver-related scholarly literature in this field. Most of the articles focused on liver dysfunction in patients with COVID-19 and the implications of the virus for gastroenterologists and hepatologists.

Mycophenolate Interruption Restores Anti-SARS-CoV-2 Vaccine Immunogenicity in Unresponsive Liver Transplant Recipients

BACKGROUND & AIMS

The fourth dose of anti-SARS-CoV-2 vaccine slightly improved the humoral response among previously seronegative liver transplant (LT) recipients. Mycophenolate (MMF) treatment worsens the vaccination response. This study aimed to evaluate whether temporary MMF interruption might improve the immunogenicity of the fourth anti-SARS-CoV-2 BNT16b2 vaccine dose in nonresponsive LT recipients.

METHODS

LT recipients negative for anti-spike glycoprotein-specific immunoglobulin G receptor-binding domain (s-RBD) antibodies after the third vaccine dose were enrolled. Anti-SARS-CoV-2 spike-specific T-cell responses were measured before and 2 months following the fourth vaccine dose, and anti-SARS-CoV-2 s-RBD antibodies also 6 months thereafter. MMF was suspended two weeks before and after vaccination.

RESULTS

Five LT recipients were enrolled. After a mean of 78 days after vaccination, all patients tested positive for anti-SARS-CoV-2 s-RBD antibodies. The mean antibody titer was 8944 UI/mL. The positive antibody response was maintained during a mean of 193 days of follow-up. Three patients developed a positive T-cell response. Two patients (one positive for T-cell response) developed a self-limited SARS-CoV-2 infection.

CONCLUSIONS

Suspending MMF prior to the fourth dose of the anti-SARS-CoV-2 mRNA vaccine seems feasible and safe. This procedure could restore vaccine-induced immunogenicity in a large portion of previously nonresponsive LT recipients.

COVID‑19 vaccination in liver transplant recipients (Review)

Severe acute respiratory syndrome coronavirus 2 (Sars-CoV-2) infection has significantly affected immunocompromised individuals and subsequently, liver transplant recipients (LTRs). Early in the course of pandemic, this vulnerable population was prioritized for vaccination, after obtaining encouraging data about the vaccination benefits on disease severity and mortality. As the published knowledge was mainly supported from studies which were limited to the healthy population, the present review summarizes the data from the literature on coronavirus disease 2019 (COVID-19) vaccination in LTRs and the available vaccination guidelines of international societies. The COVID-19 vaccination of LTRs is strongly recommended as a safe and effective measure in order to prevent severe disease and mortality.

Humoral Immune Response after COVID-19 mRNA Vaccination in Patients with Liver Cirrhosis: A Prospective Real-Life Single Center Study

Coronavirus-disease-2019 (COVID-19) mRNA vaccination effectively reduces mortality and morbidity in cirrhotic patients, but the immunogenicity and safety of vaccination have been partially characterized. The study aimed to evaluate humoral response, predictive factors, and safety of mRNA-COVID-19 vaccination in cirrhotic patients compared to healthy subjects. A prospective, single-center, observational study enrolled consecutive cirrhotic patients who underwent mRNA-COVID-19 vaccination from April to May 2021. Anti-spike-protein (anti-S) and nucleocapsid-protein (anti-N) antibodies were evaluated before the first (T0) and the second (T1) doses and 15 days after completing the vaccination. An age and sex-matched healthy reference group was included. The incidence of adverse events (AEs) was assessed. In total, 162 cirrhotic patients were enrolled, 13 were excluded due to previous SARS-CoV-2 infection; therefore, 149 patients and 149 Health Care Workers (HCWs) were included in the analysis. The seroconversion rate was similar in cirrhotic patients and HCWs at T1 (92.5% vs. 95.3%, p = 0.44) and T2 (100% in both groups). At T2, anti-S-titres were significantly higher in cirrhotic patients compared to HCWs (2776.6 vs. 1756 BAU/mL, p < 0.001]. Male sex (β = -0.32 [-0.64, -0.04], p = 0.027) and past-HCV-infection (β = -0.31 [-0.59, -0.04], p = 0.029) were independent predictors of lower anti-S-titres on multiple-gamma-regression-analysis. No severe AEs occurred. The COVID-19-mRNA vaccination induces a high immunization rate and anti-S-titres in cirrhotic patients. Male sex and past-HCV infection are associated with lower anti-S-titres. The COVID-19-mRNA vaccination is safe.

Analysis of Antibody Responses After COVID-19 Vaccination in Liver Transplant Recipients: A Single-Center Study

BACKGROUND

Liver transplant (LT) recipients were considered a vulnerable population during the coronavirus disease 2019 (COVID-19) pandemic. The clinical efficacy of the COVID-19 vaccine is unknown in immunocompromised patients. The purpose of this study was to provide evidence of antibody responses after COVID-19 vaccination in LT recipients.

METHODS

This study enrolled 46 patients who underwent LT at Samsung Medical Center (Seoul, Korea) before implementation of the one-dose vaccine in Korea. Those who completed the two-dose COVID-19 vaccine between August 2021 and September 2021 were included and followed through December 2021. Semiquantitative anti-spike serologic testing was performed using the Roche Elecsys anti-SARS-CoV-2 S enzyme immunoassay (Roche Diagnostics, Rotkereuz, Switzerland) with a positive cutoff of at least 0.8 U/mL.

RESULTS

Among all 46 participants, 40 (87%) demonstrated an antibody response after the second dose of a COVID-19 vaccine, while six (13%) had no antibody response after the second dose. Upon univariate analysis, patients with higher antibody titer had longer years since LT (2.3 ± 2.8 vs. 9.4 ± 5.0, P < 0.001). A lower median tacrolimus (TAC) level before vaccination and after the second dose of COVID-19 vaccine indicated a significantly higher antibody response (2.3 [1.6-3.2] vs. 7.0 [3.7-7.8], P = 0.006, 2.5 [1.6-3.3] vs. 5.7 [4.2-7.2], P = 0.003). Period between 2nd vaccination and serologic testing was significantly higher in the antibody-response group compared to the no-antibody-response group (30.2 ± 24.0 vs. 65.9 ± 35.0, P = 0.012). A multivariate analysis of antibody responses revealed TAC level before vaccination as a statistically significant factor.

CONCLUSION

A higher TAC level before vaccination resulted in less effective vaccination in LT patients. Booster vaccinations are required, especially for patients in the early stage after LT who have compromised immune function.

Effect of Moderate to Severe Hepatic Steatosis on Vaccine Immunogenicity against Wild-Type and Mutant Virus and COVID-19 Infection among BNT162b2 Recipients

Background: We aimed to investigate the effect of non-alcoholic fatty liver disease (NAFLD) on BNT162b2 immunogenicity against wild-type SARS-CoV-2 and variants and infection outcome, as data are lacking. Methods: Recipients of two doses of BNT162b2 were prospectively recruited. Outcomes of interest were seroconversion of neutralizing antibody by live virus microneutralization (vMN) to SARS-CoV-2 strains (wild-type, delta and omicron variants) at day 21, 56 and 180 after first dose. Exposure of interest was moderate-to-severe NAFLD (controlled attenuation parameter ≥ 268 dB/M on transient elastography). We calculated adjusted odds ratio (aOR) of infection with NAFLD by adjusting for age, sex, overweight/obesity, diabetes and antibiotic use. Results: Of 259 BNT162b2 recipients (90 (34.7%) male; median age: 50.8 years (IQR: 43.6–57.8)), 68 (26.3%) had NAFLD. For wild type, there was no difference in seroconversion rate between NAFLD and control groups at day 21 (72.1% vs. 77.0%; p = 0.42), day 56 (100% vs. 100%) and day 180 (100% and 97.2%; p = 0.22), respectively. For the delta variant, there was no difference also at day 21 (25.0% vs. 29.5%; p = 0.70), day 56 (100% vs. 98.4%; p = 0.57) and day 180 (89.5% vs. 93.3%; p = 0.58), respectively. For the omicron variant, none achieved seroconversion at day 21 and 180. At day 56, there was no difference in seroconversion rate (15.0% vs. 18.0%; p = 0.76). NAFLD was not an independent risk factor of infection (aOR: 1.50; 95% CI: 0.68–3.24). Conclusions: NAFLD patients receiving two doses of BNT162b2 had good immunogenicity to wild-type SARS-CoV-2 and the delta variant but not the omicron variant, and they were not at higher risk of infection compared with controls.

Association between Gut Microbiota and SARS-CoV-2 Infection and Vaccine Immunogenicity

Gut microbiota is increasingly recognized to play a pivotal role in various human physiological functions and diseases. Amidst the COVID-19 pandemic, research has suggested that dysbiosis of the gut microbiota is also involved in the development and severity of COVID-19 symptoms by regulating SARS-CoV-2 entry and modulating inflammation. Previous studies have also suggested that gut microbiota and their metabolites could have immunomodulatory effects on vaccine immunogenicity, including influenza vaccines and oral rotavirus vaccines. In light of these observations, it is possible that gut microbiota plays a role in influencing the immune responses to COVID-19 vaccinations via similar mechanisms including effects of lipopolysaccharides, flagellin, peptidoglycan, and short-chain fatty acids. In this review, we give an overview of the current understanding on the role of the gut microbiota in COVID-19 manifestations and vaccine immunogenicity. We then discuss the limitations of currently published studies on the associations between gut microbiota and COVID-19 vaccine outcomes. Future research directions shall be focused on the development of microbiota-based interventions on improving immune response to SARS-CoV-2 infection and vaccinations.

Impact of chronic liver disease on SARS-CoV-2 infection outcomes: Roles of stage, etiology and vaccination

Since the first identification in December of 2019 and the fast spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, it has represented a dramatic global public health concern. Though affecting mainly the respiratory system, SARS-CoV-2 disease, defined as coronavirus disease 2019 (COVID-19), may have a systemic involvement leading to multiple organ dysfunction. Experimental evidence about the SARS-CoV-2 tropism for the liver and the increasing of hepatic cytolysis enzymes during infection support the presence of a pathophysiological relationship between liver and SARS-CoV-2. On the other side, patients with chronic liver disease have been demonstrated to have a poor prognosis with COVID-19. In particular, patients with liver cirrhosis appear extremely vulnerable to infection. Moreover, the etiology of liver disease and the vaccination status could affect the COVID-19 outcomes. This review analyzes the impact of the disease stage and the related causes on morbidity and mortality, clinical outcomes during SARS-CoV-2 infection, as well as the efficacy of vaccination in patients with chronic liver disease.

COVID-19 Vaccination in Patients with Chronic Liver Disease

Vaccination against SARS-CoV-2 has become a central public health issue, primarily for vulnerable populations such as individuals with Chronic Liver Disease (CLD). Increased COVID-19-related mortality and disease severity has been noted in this subgroup of patients. Severe COVID-19 tends to further deregulate liver function in patients with chronic liver failure or cirrhosis and even reactivate hepatitis in people living with HBV or HCV. In addition, impaired hepatic function leads to several limitations in possible therapeutic interventions. Chronic hepatic dysregulation, along with the underlying cirrhosis-associated immune dysfunction (CAID), leads to a decreased immune response to vaccination that, in turn, may result in reduced efficacy rates and lowered lasting protection. According to current guidelines, timely vaccination and frequent booster shot administration are deemed necessary in this context. Vaccination-related adverse events are mostly mild in nature and similar to those reported in the general population, whereas the incidence of liver injury following vaccination is relatively rare. We aimed to review available evidence and recommendations associated with COVID-19 vaccination in patients with chronic liver disease, and provide insight to current issues and future directions.