There have been few predecessor viruses for this one, which share similarities in structure and in the way it inflicts damage to human body. Viruses self-mutate periodically, change its structure and form and take new avatars. The current avatar inducing COVID-19 spreads rapidly and has more death rate than previous generations. All previous coronaviruses were respiratory pathogens.
Liver impairment has been reported in up to 60% of patients with the preceding coronavirus — SARS-CoV. Given the fact that this novel corona (SARS-CoV-2) has 80% genetic similarity to the preceding strain of the virus (SARS-CoV), does it act similarly with reference to the liver?
Let us look at information from China. Liver damage in mild cases of COVID-19 is often temporary and the organ can return to normal without any special treatment. This could be due to the state of direct infection of liver cells or could as well be due to liver cells getting caught up in the immune war between body’s immune system and the virus with chemicals produced by our body, namely cytokines. More patients with severe disease had abnormal liver function tests than did non-severe patients with COVID. Those who tested positive for the virus (sub-clinical phase, identified by contact tracing), but did not develop symptoms had much less involvement of the liver. In short, liver injury depends on severity of COVID-19.
Cases of acute liver failure have not been reported yet from China or from other countries.
What about people who already have liver disease? People with non-alcoholic fatty liver disease (NAFLD) or its more severe form, non-alcoholic steatohepatitis (NASH), often have cardiovascular risk factors, including metabolic syndrome, obesity and diabetes, raising the risk for severe COVID-19 complications.
Although hepatitis B virus (HBV) is common in China and other Asian countries, studies so far have not reported whether HBV-related liver disease influences COVID-19 outcomes. All these liver diseases without advanced scarring or cirrhosis would not have more chance to get the virus infection though.
That is not the case with cirrhosis of liver — cirrhosis per se may be considered an immune dysfunctional state; those under medical management and those in whom a liver transplant is planned and waiting for organ allocation should also be considered at more risk.
Pre-existing disease
Those who have pre-existing liver disease, should they undergo check-up and LFTs to see if coronavirus has entered the liver? The answer is an emphatic NO. What has been mentioned here is abnormality of LFT in those patients who already developed COVID-19. COVID is a respiratory illness and will have symptoms pertaining to lung. Severe cases who are hospitalised alone may develop jaundice. Liver injury will not occur in the absence of respiratory illness and hence no screening tests/ LFT are indicated in patients with liver disease.
Are liver transplant recipients at higher risk for COVID-19?
Certainly. Those who have undergone liver transplant and are on immunosuppression medicines (anti-rejection medicines) are certainly at higher risk of getting this infection and logically, can end up with severe disease.
People with a weakened immune system may be unable to fight off the virus. So transplant patients have more chance of getting the virus, but paradoxically transplant recipients may not exhibit symptoms — fever, breathlessness — to begin with. Apart from the routine measures of frequent hand washing, hand sanitising, cough etiquette and avoiding putting hands to mouth, they should try to avoid crowds and non-essential travel.
