Can COVID-19 Cause Liver Damage and Long-Term Effects?

COVID-19 can damage the liver, and it does so far more often than most people realize. During acute infection, roughly a quarter to over a third of hospitalized patients show abnormal liver blood tests, and those with severe disease fare considerably worse. The damage comes from multiple directions at once: the virus itself, the body’s inflammatory response, oxygen deprivation, blood clotting problems, and even some of the medications used to treat the infection. For most people, liver function returns to normal within weeks or months. But a subset of patients, particularly those who were critically ill, develop lasting liver problems that can persist for a year or longer.

How Often Acute COVID-19 Affects the Liver

The liver involvement in COVID-19 became clear early in the pandemic when doctors noticed that a striking number of hospitalized patients had elevated liver enzymes on routine blood work. A systematic review and meta-analysis pooling data from multiple studies found that about 27% of patients had abnormal liver tests at admission, and that number climbed to 36% during the course of hospitalization.¹ A separate meta-analysis of global data placed the overall rate of elevated AST (a key liver enzyme) at about 23% across all patients, but that rate jumped to roughly 46% in those with severe illness, compared to 15% in milder cases.²

A large U.S. cohort study of over 2,200 COVID-positive patients broke the injury down further: 45% had mild liver enzyme elevations, 21% had moderate elevations, and about 6% had severe liver injury.³ That severe category matters because it was linked to worse clinical outcomes. The pattern of injury also had a distinctive signature: AST levels tended to run higher than ALT levels, a pattern that can hint at muscle involvement or ischemia rather than primary liver-cell damage alone.²

How COVID-19 Damages the Liver

The liver injury seen in COVID-19 is not one thing. It comes from several overlapping mechanisms, and teasing them apart in any given patient can be difficult. The virus itself may directly infect liver cells. SARS-CoV-2 enters cells through the ACE2 receptor, which is present on bile duct cells (cholangiocytes) and, to a lesser extent, on hepatocytes. This gives the virus a direct route into liver tissue.⁴

But direct viral attack is probably not the whole story, and may not even be the main driver. The three factors most consistently identified as major contributors are the cytokine storm (the body’s own exaggerated immune response), ischemia (reduced blood flow), and hypoxia (low oxygen).⁵ When the immune system floods the bloodstream with inflammatory molecules, the liver takes a hit because it filters all that blood. Add in the oxygen deprivation that severe lung disease causes, and liver cells can be starved of what they need to function.⁶

The Role of Blood Clots

COVID-19 is well known for causing abnormal blood clotting throughout the body, and the liver is no exception. Post-mortem examinations have supported the idea that tiny blood clots forming in the liver’s portal veins and sinusoids (the small vessels inside the liver) can choke off blood supply and cause damage.⁷ One study found that higher D-dimer levels (a blood marker of clotting activity) and elevated white blood cell counts were independently linked to liver enzyme elevations, pointing to microvascular thrombosis as a contributor alongside systemic inflammation.⁸

This vascular inflammation and clotting pathway represents a distinct mechanism from the cytokine storm, even though the two often travel together. The inflamed blood vessel lining (endothelium) activates platelets and triggers clot formation, creating a feedback loop that compounds liver injury.⁹

When the Treatment Itself Hurts the Liver

Some of the medications used to fight COVID-19 can cause their own liver problems, making it hard to distinguish drug-related injury from the disease itself. Remdesivir, one of the most widely used antiviral treatments during the pandemic, drew particular attention. A review of five randomized controlled trials, two case reports, and one case series covering about 2,375 patients found enough concern about liver toxicity that the authors recommended checking baseline liver function before starting the drug, avoiding other liver-stressing medications at the same time, and monitoring liver enzymes closely throughout treatment.¹⁰

Corticosteroids like dexamethasone, while life-saving in severe COVID-19, can also stress the liver and, as we will see later, create a specific risk for people carrying dormant hepatitis B. Other drugs used in hospitalized patients, from antibiotics to antipyretics, layer on additional hepatotoxic potential. For clinicians, disentangling what is “COVID liver” from what is “drug liver” remains a real challenge.

What Autopsy Studies Show

The most direct look at how COVID-19 affects liver tissue comes from autopsy studies. A review of autopsy findings reported that the most common microscopic abnormalities were congestion (seen in about 43% of cases) and steatosis, or fatty infiltration (about 42%). Inflammation and cell death within the liver were present in roughly 19% of cases, and portal inflammation in 18%. Microthrombi inside the liver’s blood vessels were actually less common than expected, appearing in only about 12% of cases, a notable contrast to the lungs, where clots were found much more frequently.¹¹

A case-control autopsy study offered a more nuanced picture. When patients with a history of chronic alcohol use were excluded, those who had died with COVID-19 were significantly more likely to have fatty liver changes (about 81% versus 50% in controls) and lobular inflammation (about 46% versus 21%).¹² The steatosis finding is particularly interesting because it suggests COVID-19 may disrupt fat metabolism in the liver, not just injure cells through inflammation or oxygen deprivation.

How Long Liver Problems Last After Recovery

For the majority of people who develop abnormal liver tests during COVID-19, the numbers do come down after the infection resolves. A follow-up study found that liver enzymes that were elevated at discharge gradually returned toward normal, with the proportion of patients showing abnormally high ALT, AST, and GGT dropping below 10% by their fourth follow-up test.¹³

But “most recover” is not the same as “everyone recovers quickly.” A one-year follow-up study tracking 118 patients told a less reassuring story. The proportion with abnormal liver function fluctuated over time: about 32% at admission, rising to roughly 55% partway through, then settling at about 29% a full year after discharge. That lingering abnormality rate was enough for the researchers to conclude that long-term monitoring is necessary.¹⁴

A cross-sectional study of people with long COVID symptoms lasting up to 20 months after infection found ongoing changes in multiple liver markers, including ALT, AST, GGT, and ferritin.¹⁵ A recent narrative review confirmed that liver manifestations in long COVID can range from silently abnormal enzyme levels to cholangiopathy (bile duct disease) and even early fibrosis, and that these can persist or progress months after the initial infection is cleared.¹⁶

An emerging tool for tracking this is ultrasound-based liver stiffness measurement. One study found that people who had recovered from COVID-19 had higher liver stiffness compared to people tested during the same time period who had not been infected, with an average increase of about 1.5 kPa. Increased stiffness can signal ongoing inflammation or early scarring.¹⁷

Post-COVID Cholangiopathy in Critically Ill Patients

The most serious long-term liver complication linked to COVID-19 is a condition called secondary sclerosing cholangitis, sometimes referred to as post-COVID cholangiopathy. This involves progressive damage to the bile ducts that can lead to chronic liver disease and, in some cases, the need for a liver transplant.¹⁸

This complication appears almost exclusively in patients who were critically ill and required invasive mechanical ventilation. A study quantifying the risk found that roughly one in every 43 invasively ventilated COVID-19 patients developed this condition. Risk factors included signs of severely reduced blood oxygen supply, multi-organ failure at admission, high fibrinogen levels, and use of intravenous ketamine.¹⁹ That rate of about one in 43 represents a dramatic clustering among ICU patients, even though it is vanishingly rare in the overall COVID-19 population.

People with Pre-existing Liver Disease Face Higher Risks

If you already have liver disease when COVID-19 strikes, the combination can be especially dangerous. People with metabolic-associated fatty liver disease (the condition formerly called nonalcoholic fatty liver disease) had roughly three times the odds of developing severe COVID-19 symptoms and about a 46% higher chance of ICU admission compared to those without fatty liver, according to a meta-analysis.²⁰

For people with cirrhosis, the picture is grimmer. Data from two large international registries showed that mortality from COVID-19 increased sharply with worsening cirrhosis severity: the odds of dying roughly doubled for those with early-stage cirrhosis and climbed to about nine times higher for those with the most advanced disease.²¹ A propensity-matched study found that late mortality was significantly higher in cirrhosis patients who had COVID-19 compared to those who had other forms of sepsis, and that about a third of surviving cirrhosis patients went on to meet the criteria for post-COVID condition.²²

Hepatitis B Reactivation

An underappreciated danger for people carrying hepatitis B is that COVID-19 treatment can trigger reactivation of the virus. A systematic review identified six studies reporting that previously suppressed or undetectable hepatitis B DNA became detectable again during or after COVID-19 treatment, sometimes escalating to fulminant liver failure. The main culprit appears to be glucocorticoid and immunosuppressive therapy, which can tip the balance between the immune system’s control of hepatitis B and the virus’s ability to replicate.²³ Case reports have confirmed that both the infection itself and the immunosuppressive treatment used against it can serve as triggers.²⁴ For anyone with a known or suspected hepatitis B history, screening and prophylactic antiviral coverage before starting steroids is a practical consideration that doctors should not overlook.

Liver Transplant Recipients

People who have received a liver transplant take immunosuppressive drugs for life, which raises an obvious concern about how they handle COVID-19. The data from multiple reviews paint a consistent picture: about 65% of transplant recipients with COVID-19 required hospitalization, roughly 23% ended up in intensive care, and around 17-22% died, though these numbers come predominantly from the earlier pandemic waves before widespread vaccination and better treatments.²⁵ A systematic review of larger datasets found similar ranges, with one propensity-matched analysis showing that liver transplant status itself did not significantly increase the risk of death once baseline characteristics were accounted for.²⁶

The question of whether to reduce immunosuppression during COVID-19 infection remains nuanced. General guidance has been to continue standard immunosuppression for mild cases, consider reducing certain drugs if the patient develops fever, low lymphocyte counts, or worsening pneumonia, and more aggressively reduce doses in severe illness.²⁵

Autoimmune Hepatitis Triggered by COVID-19

There is growing evidence that SARS-CoV-2 infection can trigger autoimmune hepatitis in people who may have been genetically predisposed but had no prior liver problems. The proposed mechanism involves molecular mimicry: viral proteins resemble certain proteins in the liver closely enough that the immune system, once ramped up to fight the virus, begins attacking liver tissue too. The resulting flood of inflammatory molecules, including tumor necrosis factor alpha, interferon gamma, and several interleukins, can activate self-reactive immune cells that specifically target the liver.²⁷

This phenomenon has also been reported, rarely, after COVID-19 vaccination. A systematic review identified 23 cases of immune-mediated liver injury following vaccination across all major vaccine platforms. Jaundice was the most common symptom, and most patients responded well to steroid treatment, with complete resolution in about 57% and ongoing recovery in another 39%.²⁸ A larger case series identified 87 patients with liver injury after vaccination, with the majority showing a hepatocellular pattern and about 57% meeting criteria for immune-mediated hepatitis. Nearly all recovered, with only one patient requiring a liver transplant.²⁹ To put these numbers in context, hundreds of millions of vaccine doses were administered globally; these cases are extremely rare and the prognosis when identified is generally excellent.

Children and Multisystem Inflammatory Syndrome

Children generally weather acute COVID-19 better than adults, but a subset develop multisystem inflammatory syndrome in children (MIS-C), an intense delayed inflammatory reaction that can affect multiple organs including the liver. In one observational study of children with MIS-C, about 52% had elevated liver enzymes, and abdominal symptoms were prominent: roughly 58% had abdominal pain, 42% developed fluid accumulation in the abdomen, and some had enlargement of the liver and spleen.³⁰

A single-center report found hepatitis in 43% of children with MIS-C, and those children had significantly more severe disease overall: higher rates of shock, greater need for respiratory support, and longer hospital stays. Inflammatory markers like ferritin and interleukin-6 were significantly higher in the hepatitis group. All patients in the study were ultimately discharged, but more than half still had persistent hepatitis at one-month follow-up.³¹

The Gut-Liver Connection

The liver receives most of its blood supply from the gut through the portal vein, which means anything that disrupts intestinal health has a direct pipeline to the liver. SARS-CoV-2 infects gut cells, causes dysbiosis (an imbalance of the normal microbial community), and increases intestinal permeability, sometimes called “leaky gut.”³² When the gut barrier breaks down, bacteria and bacterial products that normally stay confined to the intestine can translocate into the portal bloodstream and reach the liver, driving inflammation there.³³

This gut-liver axis disruption has broader consequences too. Emerging evidence suggests the communication breakdown extends bidirectionally across multiple organ systems, with gut dysbiosis influencing the severity of disease in the lungs, heart, brain, and liver simultaneously.³⁴ For the liver specifically, this means the injury is not just coming from the bloodstream’s inflammatory cargo or from the virus directly; it is also being fueled from below, through the gut.

Sex Differences in COVID-19 Liver Injury

Men appear to be significantly more susceptible to liver damage from COVID-19 than women. A cross-sectional study found that about 68% of infected males had abnormal liver function compared to roughly 38% of females, with AST and ALT levels differing significantly between the sexes.³⁵ The same study found that age was not a significant independent predictor once other factors were considered. The sex difference aligns with the broader pattern seen throughout COVID-19 research: men tend to have more severe disease and worse outcomes across most organ systems. Why exactly this happens remains debated, but differences in ACE2 expression, baseline inflammatory profiles, and hormonal factors have all been proposed as contributors.