Effectiveness of COVID-19 Viral Vector Ad.26.COV2.S Vaccine and Comparison with mRNA Vaccines in Cirrhosis

COVID-19 Vaccination in Liver Cirrhosis: Safety and Immune and Clinical Responses

Introduction

Three years after the beginning of the SARS-CoV-2 pandemic, the safety and efficacy of COVID-19 vaccination in liver cirrhosis (LC) patients remain controversial. We aimed to study the safety, immunological, and clinical responses of LC patients to COVID-19 vaccination.

Methods

Prospective multicentric study in adults with LC eligible for COVID-19 vaccination, without prior known infection. Patients were followed up until the timing of a booster dose, SARS-CoV-2 infection, or death. Spike-protein immunoglobulin G antibody titers for SARS-CoV-2 at 2 weeks, 3 months, and 6 months postvaccination were assessed. Antibody titers <33.8 binding antibody units (BAU)/mL were considered seronegative and <200 BAU/mL suboptimal. Postvaccination infection and its severity were registered.

Results

We included 124 LC patients, 81% males, mean aged 61 ± 10 years, with a mean follow-up of 221 ± 26 days. Alcohol was the most common (61%) cause of cirrhosis, and 7% were under immunosuppressants for autoimmune hepatitis; 69% had portal hypertension, 42% had a previous decompensation, and 21% had a Child-Pugh-Turcotte score of B/C. The type of vaccine administrated was BNT162b2 (n = 59, 48%), ChAdOx1nCoV-19 (n = 45, 36%), mRNA-1273 (n = 14, 11%), and Ad26.COV2.S (n = 6, 5%). Eighteen percent of the patients reported adverse events after vaccination, none serious. Median [Q1; Q3] antibody titers were 1,185 [280; 2,080] BAU/mL at 2 weeks, 301 [72; 1,175] BAU/mL at 3 months, and 192 [49; 656] BAU/mL at 6 months. There were seronegative and suboptimal antibody responses in 8% and 23% of the patients at 2 weeks, 16% and 38% at 3 months, and 22% and 48% at 6 months. Older age and adenovirus vector vaccines were the only factors associated with seronegative and suboptimal responses at 2 weeks and 3 months (p < 0.05) in a multivariable logistic regression analysis. Eleven patients (9%) were infected with SARS-CoV-2 during follow-up (3.8-6.6 months postvaccination), all with mild disease. There were no differences regarding the type of vaccine, and 73% had antibody titers >200 BAU/mL at 3 months.

Conclusion

COVID-19 vaccines in patients with LC were safe, without serious adverse events. The humoral and clinical responses were similar to the reported for the general population. Humoral response was adversely impacted by older age and adenovirus vector vaccines and unrelated to the liver disease severity.

Methodology of comparative studies on the relative effectiveness of COVID-19 vaccines: a systematic review

BACKGROUND

This study aimed to comprehensively outline the methodological approaches used in published research comparing the vaccine effectiveness (VE) of coronavirus disease 2019 (COVID-19) vaccines.

METHODS

A systematic search was conducted on June 13, 2024, to identify comparative studies evaluating the effectiveness of mRNA versus non-mRNA and monovalent versus bivalent COVID-19 vaccines. We screened titles, abstracts, and full texts, collecting data on publication year, country, sample size, study population composition, study design, VE estimates, outcomes, and covariates. Studies that reported relative VE (rVE) were analyzed separately from those that did not.

RESULTS

We identified 25 articles comparing rVE between mRNA and non-mRNA COVID-19 vaccines, as well as between monovalent and bivalent formulations. Among the studies assessing VE by vaccine type, 126 did not provide rVE estimates. Comparative VE studies frequently employed retrospective cohort designs. Among the definitions of rVE used, the most common were hazard ratio and absolute VE, calculated as (1-odds ratio)×100. Studies were most frequently conducted in the United Kingdom and the United States, and the most common outcome was infection. Most targeted the general population and assessed the VE of mRNA vaccines using the AstraZeneca vaccine as a reference. A small proportion, 7.3% (n=11), did not adjust for any variables. Only 3 studies (2.0%) adjusted for all core confounding variables recommended by the World Health Organization.

CONCLUSION

Few comparative studies of COVID-19 vaccines have incorporated rVE methodologies. Reporting rVE and employing a consistent set of covariates can broaden our understanding of COVID-19 vaccines.

Evaluating the protective effectiveness and risk factors of ursodeoxycholic acid on COVID-19 among outpatients

Objective: This study aimed to assess the chemopreventive effect of ursodeoxycholic acid (UDCA) against COVID-19 and to analyze infection risk factors, symptoms, and recovery in outpatients with UDCA exposure. Methods: The study enrolled outpatients prescribed UDCA from the Second Affiliated Hospital of Chongqing Medical University, China, between 01 July 2022, and 31 December 2022. Data on demographics, comorbidities, and drug combinations were collected using electronic medical records. COVID-19 infection, symptoms, severity, prognosis, vaccinations, and UDCA administration were surveyed by telephone interviews. UDCA non-users served as controls and were matched in a 1:2 ratio with UDCA users using propensity score matching with the nearest neighbor algorithm. Infection rates, symptomatology, severity, and prognosis were compared between matched and control cohorts, and risk factors and infection and recovery symptoms were analyzed in UDCA-exposed outpatients. Results: UDCA-exposed outpatients (n = 778, 74.8%) and matched UDCA users (n = 95, 74.2%) showed significantly lower SARS-CoV-2 infection rates than control patients (n = 59, 92.2%) (p < 0.05). The matched UDCA group exhibited substantially lower fever, cough, sore throat, and fatigue rates than controls (p < 0.05). Participants with UDCA exposure generally experienced mild symptoms, while those without UDCA had moderate symptoms. The matched UDCA group also had significantly shorter durations of fever and cough (p < 0.05). Risk factors such as age over 60, less than 1 month of UDCA administration, diabetes mellitus, and coronary artery disease significantly increased SARS-CoV-2 infection rates (p < 0.05), while smoking led to a decrease (p < 0.05). Hypertension was associated with a prolonged COVID-19 recovery (p < 0.05), while smoking, vaccination, and fatty liver disease were associated with shorter recovery periods (p < 0.05). The main symptoms in the full UDCA cohort were fever, cough, and sore throat, with fatigue, cough, and hyposthenia being the most persistent. Conclusion: UDCA demonstrated chemopreventive effect against SARS-CoV-2 in outpatients by significantly reducing infection incidence and mitigating COVID-19 symptoms, severity, and recovery duration. Old age, short UDCA course, and comorbidities such as diabetes mellitus and CAD increased infection rates, while hypertension prolonged recovery. Smoking, vaccination, and fatty liver disease reduced infection rates and shortened recovery. UDCA had minimal impact on symptom types. Larger and longer-term clinical studies are needed further to assess UDCA's effectiveness in COVID-19 prevention or treatment.

Ursodeoxycholic acid is associated with a reduction in SARS-CoV-2 infection and reduced severity of COVID-19 in patients with cirrhosis

BACKGROUND AND AIMS

Studies have demonstrated that reducing farnesoid X receptor activity with ursodeoxycholic acid (UDCA) downregulates angiotensin-converting enzyme in human lung, intestinal and cholangiocytes organoids in vitro, in human lungs and livers perfused ex situ, reducing internalization of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) into the host cell. This offers a potential novel target against coronavirus disease 2019 (COVID-19). The objective of our study was to compare the association between UDCA exposure and SARS-CoV-2 infection, as well as varying severities of COVID-19, in a large national cohort of participants with cirrhosis.

METHODS

In this retrospective cohort study among participants with cirrhosis in the Veterans Outcomes and Costs Associated with Liver cohort, we compared participants with exposure to UDCA, with a propensity score (PS) matched group of participants without UDCA exposure, matched for clinical characteristics, and vaccination status. The outcomes included SARS-CoV-2 infection, symptomatic, at least moderate, severe, or critical COVID-19, and COVID-19-related death.

RESULTS

We compared 1607 participants with cirrhosis who were on UDCA, with 1607 PS-matched controls. On multivariable logistic regression, UDCA exposure was associated with reduced odds of developing SARS-CoV-2 infection (adjusted odds ratio [aOR] 0.54, 95% confidence interval [CI] 0.41-0.71, p < 0.0001). Among patients who developed COVID-19, UDCA use was associated with reduced disease severity, including symptomatic COVID-19 (aOR 0.54, 95% CI 0.39-0.73, p < 0.0001), at least moderate COVID-19 (aOR 0.51, 95% CI 0.32-0.81, p = 0.005), and severe or critical COVID-19 (aOR 0.48, 95% CI 0.25-0.94, p = 0.03).

CONCLUSIONS

In participants with cirrhosis, UDCA exposure was associated with both a decrease in SARS-CoV-2 infection, and reduction in symptomatic, at least moderate, and severe/critical COVID-19.

FXR inhibition may protect from SARS-CoV-2 infection by reducing ACE2

Preventing SARS-CoV-2 infection by modulating viral host receptors, such as angiotensin-converting enzyme 2 (ACE2)1, could represent a new chemoprophylactic approach for COVID-19 that complements vaccination2,3. However, the mechanisms that control the expression of ACE2 remain unclear. Here we show that the farnesoid X receptor (FXR) is a direct regulator of ACE2 transcription in several tissues affected by COVID-19, including the gastrointestinal and respiratory systems. We then use the over-the-counter compound z-guggulsterone and the off-patent drug ursodeoxycholic acid (UDCA) to reduce FXR signalling and downregulate ACE2 in human lung, cholangiocyte and intestinal organoids and in the corresponding tissues in mice and hamsters. We show that the UDCA-mediated downregulation of ACE2 reduces susceptibility to SARS-CoV-2 infection in vitro, in vivo and in human lungs and livers perfused ex situ. Furthermore, we reveal that UDCA reduces the expression of ACE2 in the nasal epithelium in humans. Finally, we identify a correlation between UDCA treatment and positive clinical outcomes after SARS-CoV-2 infection using retrospective registry data, and confirm these findings in an independent validation cohort of recipients of liver transplants. In conclusion, we show that FXR has a role in controlling ACE2 expression and provide evidence that modulation of this pathway could be beneficial for reducing SARS-CoV-2 infection, paving the way for future clinical trials.

Efficacy, Safety and Immunogenicity of Anti-SARS-CoV-2 Vaccines in Patients with Cirrhosis: A Narrative Review

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing coronavirus disease 2019 (COVID-19), has led to a pandemic with more than 6.5 million deaths worldwide. Patients with liver cirrhosis (PWLC) are regarded as prone to severe COVID-19. Vaccination against SARS-CoV-2 has been proven to be the most effective measure against COVID-19 and a variety of different vaccines have been approved for use; namely mRNA and vector-based, inactivated, whole virion, and protein subunit vaccines. Unfortunately, only a small number of PWLC were included in phase I-III vaccine trials, raising concerns regarding their efficacy and safety in this population. The authors, in this review, present available data regarding safety and efficacy of anti-SARS-CoV-2 vaccination in PWLC and discuss post-vaccination antibody responses. Overall, all vaccines seem to be extremely safe, with only a few and insignificant adverse events, and efficient, leading to lower rates of hospitalization and COVID-19-related mortality. T- and B-cell responses, on the other hand, remain an enigma, especially in patients with decompensated disease, since these patients show lower titers of anti-SARS-CoV-2 antibodies in some studies, with a more rapid waning. However, this finding is not consistent, and its clinical impact is still undetermined.

SARS-CoV-2 Infection and Liver Disease: A Review of Pathogenesis and Outcomes

The impact of the coronavirus disease 2019 (COVID-19) pandemic has been immense, and it continues to have lasting repercussions. While the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus primarily infects the respiratory system, other organ systems are affected, including the liver. Scientific knowledge on the role of SARS-CoV-2 infection and liver injury has evolved rapidly, with recent data suggesting specific hepatotropism of SARS-CoV-2. Moreover, additional concerns have been raised in regard to long-term liver damage, related to emerging cases of post-COVID-19 cholangiopathy and chronic cholestasis. Great effort has also been focused on studying how specific subpopulations with chronic medical conditions might be disproportionately impacted by COVID-19. One such population includes individuals with chronic liver disease (CLD) and cirrhosis, with an expanding body of research indicating these patients being particularly susceptible to adverse outcomes. In this review, we provide an updated summary on the current pathogenesis and mechanism of liver injury in the setting of SARS-CoV-2 infection, the association between health outcomes and SARS-CoV-2 infection in patients with CLD, and the unique consequences of the COVID-19 pandemic on the routine care of patients with CLD.

COVID-19 vaccination and liver disease

Various vaccines against severe acute respiratory syndrome coronavirus 2 have been developed in response to the coronavirus disease 2019 (COVID-19) global pandemic, several of which are highly effective in preventing COVID-19 in the general population. Patients with chronic liver diseases (CLDs), particularly those with liver cirrhosis, are considered to be at a high risk for severe COVID-19 and death. Given the increased rates of disease severity and mortality in patients with liver disease, there is an urgent need to understand the efficacy of vaccination in this population. However, the data regarding efficacy and safety of COVID-19 vaccination in patients with CLDs is limited. Indeed, several organ-specific or systemic immune-mediated side effects following COVID-19 vaccination, including liver injury similar to autoimmune hepatitis, have been recently reported. Although the number of cases of vaccine-related liver injury is increasing, its frequency, clinical course, and mechanism remain unclear. Here, we review the current findings on COVID-19 vaccination and liver disease, focusing on: (1) The impact of COVID-19 in patients with CLD; (2) The efficacy, safety, and risk-benefit profiles of COVID-19 vaccines in patients with CLD; and (3) Liver injury following COVID-19 vaccination.

Third dose of COVID-19 mRNA vaccine appears to overcome vaccine hyporesponsiveness in patients with cirrhosis

BACKGROUND & AIMS

Cirrhosis is associated with immune dysregulation and hyporesponsiveness to several vaccines including those against COVID-19. Our aim was to compare outcomes between patients with cirrhosis who received 3 doses of either the Pfizer BNT162b2 mRNA or Moderna mRNA-1273 vaccines to a propensity-matched control group of patients at similar risk of infection who received 2 doses.

METHODS

This was a retrospective cohort study of patients with cirrhosis who received 2 or 3 doses of a COVID-19 mRNA vaccine at the Veterans Health Administration. Participants who received 3 doses of the vaccine (n = 13,041) were propensity score matched with 13,041 controls who received 2 doses, and studied between July 18, 2021 and February 11, 2022, when B.1.617.2 (delta) and B.1.1.529 (omicron) were the predominant variants. Outcomes were aggregated as all cases with COVID-19, symptomatic COVD-19, with at least moderate COVID-19, or severe or critical COVID-19.

RESULTS

Receipt of the third dose of a COVID-19 mRNA vaccine was associated with an 80.7% reduction in COVID-19 (95% CI 39.2-89.1, p <0.001), an 80.4% reduction in symptomatic COVID-19, an 80% reduction in moderate, severe or critical COVID-19, (95% CI 34.5-87.6%, p = 0.005), a 100% reduction in severe or critical COVID-19 (95% CI 99.2-100.0, p = 0.01), and a 100% reduction in COVID-19-related death (95% CI 99.8-100.0, p = 0.007). The magnitude of reduction in COVID-19 was greater with the third dose of BNT 162b2 than mRNA-1273 and among participants with compensated rather than decompensated cirrhosis.

CONCLUSIONS

Administration of a third dose of a COVID-19 mRNA vaccine was associated with a more significant reduction in COVID-19 in patients with cirrhosis than in the general population, suggesting that the third dose can overcome vaccine hyporesponsiveness in this population.

LAY SUMMARY

Cirrhosis is associated with decreased responsiveness to several vaccines, including those against COVID-19. In this study of 26,082 participants with cirrhosis during the delta and omicron surge, receipt of the third dose of the vaccine was associated with an 80% reduction in COVID-19, a 100% reduction in severe/critical COVID-19, and a 100% reduction in COVID-19-related death. These findings support the importance of a third dose of mRNA vaccine among patients with cirrhosis.