During the pandemic, COVID-19 was largely understood through its respiratory symptoms. As clinical data accumulated, it became clear that the virus also affect other organs, including the liver. Changes in liver function tests were observed in a proportion of patients, including those without prior liver disease.
In most cases, these changes are mild and resolve over time. However, they raise a more relevant question: what happens after the infection has resolved, particularly once daily routines have resumed and are these effects always recognised? The liver plays a role in this phase of recovery, not as a primary site of disease, but as an organ involved in how the body responds to and stabilises after infection. While lasting complications are uncommon, these findings suggest that recovery may not always be captured by symptoms alone.
What clinicians started noticing
Clinicians observed consistent patterns in liver-related blood tests during COVID-19 infection, most commonly a rise in liver enzymes. Detected through routine blood tests, these changes indicate that the liver is under stress or temporarily not functioning at its usual level. This is one of the most common signs of temporary liver dysfunction during illness. In mild cases, they typically settle as patients recover, while in more severe illness or in those with underlying conditions, they may be more pronounced and require closer monitoring.
The broader implication is straightforward. The liver is often involved when the body is under physiological stress, and COVID-19 is no exception. In most cases, this doesn’t lead to long-term damage, but it reflects how the body responds to infection.
While COVID-19 is widely known as a respiratory illness, its effects aren’t limited to the lungs. As Dr Ng, Internal Medicine & Infectious Diseases Physician, explains, the virus can also affect the liver, even in individuals with no prior liver disease, raising the question of how the virus can affect the liver in people with no prior liver disease.
In our local study of 1,246 COVID-19 patients at Universiti Malaya Medical Centre (UMMC), liver dysfunction was observed in 58.7% of patients1.
SARS-CoV-2 can affect the liver through multiple mechanisms. The virus binds to ACE2 receptors highly expressed in cholangiocytes (bile duct cells)2. Injury can occur through direct viral infection, with viral RNA detected in liver specimens3, as well as indirect mechanisms. These include the body’s inflammatory response, often referred to as cytokine storm with elevated IL-6 and TNF-α4, reduced oxygen supply to the liver (hypoxic injury), drug-induced liver injury (DILI), and thrombosis5.
Even previously healthy individuals can develop hepatocyte damage (liver cell) from the intense inflammatory response.
Why the liver is involved
The liver plays a central role in maintaining internal balance. It processes nutrients, filters toxins, and helps regulate inflammation, functions that become especially important during illness when multiple systems are under strain. When the body responds to infection, the liver supports these processes continuously, even as symptoms begin to improve.
COVID-19 can influence the liver through several pathways. The immune response can drive inflammation that temporarily affects liver function. The virus may also affect cells in the liver and bile ducts. In more severe cases, medications and reduced oxygen levels can add further strain. Even in people without prior liver disease, these combined factors can affect how the liver functions during infection, although these effects are usually temporary and resolve over time.
The most frequently observed liver abnormalities during or after COVID-19 infection are mild to moderate elevations in aminotransferases, which are enzymes that reflect liver cell injury, and these are typically identified through routine liver function tests in clinical practice.
In our Malaysian cohort, a mixed-pattern liver injury, involving both hepatocellular and cholestatic features, was most common (67.8%), with elevated GGT (82.8%, a marker linked to bile duct function), AST (75.5%, an enzyme released when liver cells are under stress or injured), and ALT (67.7%, an enzyme more specific to liver cell injury) being the predominant abnormalities6.
Globally, an estimated 15–65% of COVID-19 patients experience some degree of liver dysfunction7. Notably, AST elevation often precedes ALT and has been associated with higher mortality in severe cases8. We also observed that severe COVID-19 and the Delta variant were linked to higher rates of liver injury1.
These abnormalities are typically identified through routine liver function tests during hospitalisation, allowing clinicians to monitor enzyme levels and assess the extent of liver involvement.
After recovery: What often goes unnoticed
What happens after infection is often less clearly defined. For many, recovery appears straightforward, particularly when symptoms resolve and daily activities return to normal. However, different parts of the body recover at different rates.
Persistent fatigue is one of the most commonly reported experiences after infection. It’s often part of post-viral recovery, but it can also reflect how the body continues adjusting, particularly in how it manages inflammation and energy. The liver supports many of these processes, but it can be under strain without producing obvious symptoms.
Liver-related symptoms tend to be non-specific. They may include fatigue that doesn’t improve with rest, reduced appetite, mild discomfort in the upper right abdomen, nausea, or bloating. In less common cases, darker urine or pale stools may occur. These symptoms are common during recovery from many infections, which makes them easy to dismiss once daily life resumes, whether that is returning to work, exercise, or regular routines.
If you’ve returned to your usual routine but still feel different from your usual baseline, particularly when energy levels don’t quite return as expected, it may not be something you would immediately connect to the infection. That gap between feeling recovered and fully recovered is where these changes are often missed, particularly when symptoms are mild.
Liver enzyme abnormalities can occur even in mild cases of COVID-19, as Dr Ng notes, raising the question of how common these changes are in individuals who recover at home and when follow-up testing should be considered.
In our 6-month follow-up study of 174 patients with initial liver dysfunction, approximately 52% had normalised liver tests by 6 months, while 48% had persistent abnormalities6. Persistent abnormalities were associated with higher BMI, elevated LDL, and the presence of metabolic-associated fatty liver disease (MAFLD).
For individuals who recovered at home, follow-up testing should be considered if there are persistent symptoms such as fatigue or abdominal discomfort, or if there are underlying metabolic risk factors including obesity or diabetes mellitus. In general, repeat testing at 4 to 6 weeks post-recovery is reasonable for those who had documented abnormalities during the acute phase of illness.
Who may be more vulnerable
Not everyone faces the same level of risk. Individuals with underlying liver conditions, such as non-alcoholic fatty liver disease (also referred to as metabolic-associated fatty liver disease, or MAFLD), chronic hepatitis B or hepatitis C, or cirrhosis, are more likely to experience more pronounced effects during infection. In these groups, the liver is already under strain, making it more susceptible to additional stress. In these groups, recovery may not always follow the same pattern, which is why changes after infection are more likely to go unnoticed.
People with metabolic risk factors, including obesity and type 2 diabetes, may also be more vulnerable. This is particularly relevant across parts of Asia, where fatty liver disease and hepatitis B are more prevalent and often develop without obvious symptoms. In many cases, underlying liver risk exists long before it’s recognised, which can influence how the body responds during infection and recovery.
Patients with pre-existing chronic liver disease (CLD) face higher risks when infected with COVID-19, particularly because the virus can interact with conditions such as fatty liver disease, hepatitis B or C, and cirrhosis, with some groups more vulnerable to complications.
In our study, 62.1% of patients with liver dysfunction had underlying CLD, most commonly metabolic-associated fatty liver disease (MAFLD) (56.9%)6. Patients with CLD also had higher liver stiffness on FibroScan, indicating more advanced underlying disease, and had higher rates of persistent liver abnormalities.
Those with cirrhosis face a markedly increased risk of mortality from COVID-199. MAFLD, particularly when accompanied by metabolic syndrome, is also associated with more severe outcomes. Our data further showed that patients with CLD were more likely to develop severe COVID-19 and took longer to achieve normalisation of liver tests1,6.
The groups at highest risk include individuals with advanced fibrosis, metabolic comorbidities such as obesity, diabetes mellitus, and hypertension, as well as those with active liver inflammation.
When it makes sense to check in
If fatigue continues for several weeks, if appetite or digestion feels noticeably different, or if there’s ongoing discomfort without a clear explanation, these are reasonable points to raise during a consultation. This is particularly relevant for those with existing metabolic or liver-related conditions, where baseline risk may already be present. In these situations, changes may be less obvious but still worth noticing.
In many cases, a simple liver function test is enough to provide reassurance. For some, results will be normal. For others, it may highlight the need for monitoring or small adjustments to support recovery, depending on the individual’s overall health profile. In some cases, this may also prompt a broader review of routine health checks, particularly for individuals with metabolic risk factors or known liver conditions, where periodic monitoring of liver function is already part of standard care.
With repeated COVID-19 infections now more common, there is growing concern about potential cumulative or longer-term effects on liver health, particularly among individuals with metabolic risk factors such as fatty liver disease, as Dr Ng highlights.
This is still an emerging area requiring further research. While most COVID-19-related liver injury is transient, our 6-month follow-up revealed that nearly half (47.7%) of patients had persistent liver abnormalities6. Those with persistent abnormalities had higher rates of metabolic-associated fatty liver disease (MAFLD) and underlying metabolic risk factors.
The Delta variant was also associated with significantly higher rates of liver injury compared to earlier strains (38.8% vs 17.1%)1, suggesting possible variant-specific effects.
With repeated infections, persistent inflammation, oxidative stress, and recurrent cytokine activation may theoretically contribute to accelerated fibrosis progression, particularly in metabolically vulnerable populations.
For individuals with metabolic risk factors, maintaining liver health becomes increasingly important. This includes weight management, diabetes mellitus control, vaccination, and periodic monitoring with liver function tests and potentially FibroScan.
Long-term studies are still needed to establish the extent and clinical significance of these risks.
What matters after recovery
The liver can be under strain without producing noticeable symptoms. COVID-19 has shown that recovery doesn’t always end when symptoms do, and that some effects can continue beyond the point where the illness seems to have passed. These observations reflect a growing understanding of how the body responds to infection, particularly in individuals with underlying liver conditions or metabolic risk factors.
For most people, feeling better is a reliable sign of recovery. But not always.
Dr Ng Rong Xiang
Medical Lecturer, Universiti Malaya (UM), Malaysia
Internal Medicine & Infectious Diseases Physician,
UM Specialist Centre , Malaysia
LinkedIn: @Kevin Ng Rong Xiang
This article was produced by Healthful For You. The views and opinions expressed throughout are those of the authors and do not necessarily reflect those of the Expert Contributor. The Expert Contributor has provided input solely for the EXPERT INSIGHT and TIP segments, based on their professional expertise. These comments are intended to offer general guidance and may not apply to all individuals. Any interpretations or conclusions beyond that section are those of Healthful For You. This article is not a substitute for personalised medical advice, diagnosis, or treatment. Please consult your doctor or a healthcare professional regarding your specific health needs.
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