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

The COVID-19 pandemic has been associated with a disruption of care and worsening outcomes of patients with liver disease.1 Fortunately, receipt of 2 doses of mRNA vaccine was associated with a 78.6% reduction in COVID-19 infection in cirrhosis.2 Although mRNA vaccines have been more widely administered in the United States, viral vector vaccines that use replication-deficient viral vectors, such as adenovirus to induce transient expression of the SARS-CoV-2 spike protein, have been the mainstay of COVID-19 vaccination worldwide.