LAUSR

Background: Information about effects of vaccination against SARS-CoV2 in patients with preexisting chronic liver disease is insufficient. The present study aims to describe the prevalence of adverse effects associated with vaccination against SARS-CoV2 in patients with chronic liver diseases. Methods: cross-sectional, analytic, prospective, observational study carried out during May 2021, through the application of a survey designed for the purposes of this research with the aim to determine the prevalence of the diverse adverse effects related to the various SARS-CoV2 vaccines in realworld patients with preexisting liver disease. Prevalence was compared with that described worldwide. Results: 310 digital surveys were applied. 53.2% (N=165) from Mexico, 8% (N=25) from United States and 38.7% (N=120) from other countries. The age group with the highest participation was that between 51 to 55 years old (18.3%, N=57). The predominant liver disease was Autoimmune Hepatitis 25.4% (N=79), followed by MAFLD in 20.3% (N= 63). Predominant stage of cirrhosis according to Child-Pugh score was A in 21.9% (N=67). 89.9% (N=279) received at least one dose of anti-COVID19 vaccine. The predominant vaccine applied was Pfizer Bion-Tech in 34.8% (N= 108), followed by Sinovac in 19.9% (N=62) and Sputnik V in 11.6% (N=36). 86.4% (N=268) presented at least one adverse effect after any of the vaccine doses applied. The predominant adverse effect reported was pain in application site in 66% (N=204). 18.8% (N=58) presented liver decompensation after application of any dose. The predominant decompensation was ascites in 4.5% (N=14), followed by hepatic encephalopathy in 3.5% (N=11). 1.26% (N=4) presented serious adverse effects: 0.3% (N=1) anaphylaxis, and 0.96% (N=3) ascending paralysis compatible with Guillain-Barre syndrome. No vaccine-related deaths were reported. When compared with worldwide data, we found no difference in prevalence of general adverse effects (p 0.84), nor in severe adverse effects (p 0.2). Conclusion: We found no difference in prevalence of SARSCoV2 vaccine-related adverse effects among chronic liver disease patients as compared to worldwide reported data. These vaccines appear to be safe in this particular group. To our knowledge, this is the first study to report the effects of these vaccines in real world liver patients.