Patients who had liver transplants or those with advanced liver fibrosis may not be adequately protected against COVID-19 after two doses of the Pfizer-BioNTech vaccine, in light of the findings of a new study presented Wednesday on the opening day of the International Liver Congress(ILC) 2021.

Presenting abstracts from the soon-to-be-released study on Wednesday, Dr Rifaat Safadi, director of the Liver Unit at Hadassah Hebrew University Medical Center, in Jerusalem, Israel, said the study suggests that such patients with low levels of antibodies to the SARS-CoV-2 virus should get a third booster Pfizer shot to increase their chances of protection against the virus.

The global virtual conference, convened by the European Association for the Study of the Liver (EASL), is taking place Wednesday – Saturday.  This year’s conference brings together leading liver disease researchers from around the world to explore new science around the prevention and treatment of liver disease caused by Hepatitis C, alcohol abuse and other risk factors, as well as the  impact of the COVID-19 pandemic on people living with liver diseases and on liver disease medications.

This year’s conference proceedings are highlighting the extreme vulnerability of people with liver disease to COVID – with one new study finding the chronic liver disease increased the odds of COVID-19 death by  80%.

On the more positive side, another study however, found that the antiretroviral drug, tenofovir, prevented serious COVID-19 illness amongst people living with chronic Hepatitis B.

Research on the impact of COVID-19 on alcohol-related liver disease is also being showcased at this year’s conference session, along with new or improved treatments for people suffering from HCV. 

“We are beginning to understand  more clearly just how disproportionately COVID-19 is impacting on people living with liver-related diseases and the studies presented at  ILC 2021 advance  our knowledge on multiple fronts, knowledge that can potentially help inform policy responses to the  pandemic going forward,” said Philip Newsome, General  Secretary of EASL and Director of the Centre for Liver Research at the University of Birmingham in the UK, at Wednesday’s opening session. 

Pfizer-BioNTech Vaccine Offers Low Immunity for People with Advanced Liver Disease

With regards to the Pfizer vaccine on patients with liver disease, Safadi, who will present the full results of the Israeli study on Saturday, explained that “older age”, advanced fibrosis and decreased steatosis appear to be risk factors for lower vaccine response among people with related forms of liver disease.

The study analysed data from 88 patients living with hepatic fibrosis who had tested positive for COVID-19  and who had received both doses of Pfizer’s-BioNTech vaccine.

It found that elderly patients with advanced liver fibrosis had a lower response to Pfizer’s vaccine, with Safadi suggesting that those patients may need a third booster shot.

“Therefore, we have to think about the booster vaccination… we are thinking now about boosting the third shot, especially those with high risk for non responsiveness or lower response,” said Safadi.

The study’s recommendation, however, goes beyond current US Food and Drug Administration (FDA) recommendations.  The FDA has so far not recommended the use of  antibody tests to check the effectiveness of vaccination against the virus, nor has it  approved a three-dose regimen or booster of any SARS-CoV-2 vaccine.

Tenofovir Reduces Severity of COVID-19 in Patients with Chronic Hepatitis B  

Encouraging data from another new study found that antiretroviral drug, tenofovir, prevented serious COVID-19 illness amongst people living with chronic Hepatitis B.

Beatriz Mateos Muñoz, PhD Specialist in Gastroenterology and Hepatology at the Hospital Universitario Ramón in Spain, said the study analysed data from 4736 patients from 28 Spanish hospitals. 

Of the 117 COVID-19 positive patients who were identified, 67  were taking  tenofovir  and 50 were on entecavir, an antiviral drug in the treatment of hepatitis B virus infection.  Muñoz said the incidence of COVID-19 in patients on tenofovir or entecavir were similar, but that patients on entecavir “more often had severe COVID-19, required ICU, ventilatory support, had longer hospitalization or died”.

The study found that tenofovir seemed to offer some protection in patients with chronic  hepatitis B infected by COVID-19.

“In multivariate logistic regression adjusted by age, sex, obesity, comorbidities and fibrosis stage, tenofovir reduced by 6-fold the risk of severe COVID-19. Patients with chronic  hepatitis B on tenofovir have a lower risk of severe COVID-19 infection than those on entecavir.”

COVID-19 Related Alcohol Sales May Have Increased Alcohol-related Liver Disease

Abdel-Aziz Shaheen, assistant professor at the Gastroenterology and Hepatology at the University of Calgary in Canada, said a large population-based study found a significant increase in the number of patients with alcoholic hepatitis who were hospitalised last year in Alberta, Canada  last year, with the highest admission rate recorded in April 2020.

Shaheen said a significant increase in alcohol sales across Europe and North America during the early months of the pandemic had alarming consequences for patients with alcoholic hepatitis. He said most of the newer patients with alcoholic hepatitis were younger and mainly from rural areas.

“There was a significant 9% increase in alcoholic hepatitis admissions per month between March and September and the average rate of alcoholic hepatitis hospitalizations compared to overall hospitalizations rate doubled from 11.6/ 10,000 general hospitalizations to 22.1/ 10,000 general hospitalizations for the same period,” said Shaheen.

More worrying, said Shaheen was that: “Our results show that the increase in alcohol sales post pandemic will significantly impact the natural history of alcoholic liver disease in Canada”. 

Chronic Liver Disease Increased the Odds of Covid-19 Death by 80%

Another study that used the French National Hospital Discharge database for patients who were hospitalised for COVID-19 found that chronic liver disease increased the odds of COVID-19 death by  80%.

Vincent Mallet, Managing Senior Physician and Professor, Hepatology Unit, Cochin University said the hospital records showed that  3, 943 of the 16,338 patients diagnosed with chronic liver disease who were admitted for Covid-19 in France in 2020 died, including 2518 after liver-related complications.

He said liver complications and alcohol use disorders may have contributed to the COVID-19 deaths of patients with chronic liver disease.

People with Obesity & Diabetes Related Fatty Liver Disease Also at Higher Risk from COVID-19

Similarly, a small study in Mexico of 348 patients found that people living with Metabolic Associated  Fatty Liver Disease (MAFLD) were five times more likely to die during hospitalization for COVID-19 than people without these factors.  

The patients studied were admitted with the SARS-COV-2 infection to a number of  tertiary referral hospitals between 4 April and 24 June 2020, said Martin Uriel Vázquez Medina, Researcher at the Laboratory of Biomathematical and Biostatistical Modelling for Health Escuela Superior de Medicina, México. 

Major risk factors for the chronic conditions are obesity and type-2 diabetes, common conditions in many parts of Latin America, also closely associated with unhealthy diets, including high sugar consumption, and lack of physical activity. 

Medina added: “We also want to show with this result that [patients in] Latin American countries that have this overhead problem of obesity, diabetes, and pre-diabetes, could also be associated with increased risk from COVID-19”.

The ILC continues until Saturday.