Hepatitis G: the virus that does not harm the liver

If you were told you have “hepatitis G” or that you tested positive for the GB-C virus, the short answer is reassuring: there is no evidence that this virus harms the liver. Despite its name, we now know it does not cause hepatitis or liver disease, which is why testing for it is not recommended as a routine.

The name is a leftover from a time when it was thought to be another cause of hepatitis transmitted through transfusions. Over the years, studies ruled that idea out. So much so that the scientific community stopped calling it a “hepatitis virus,” and today it is known as human pegivirus (HPgV).

A virus with a history and several names

In the 1990s, two research groups independently described two supposed new viruses: the GB-C virus (GBV-C) and the hepatitis G virus (HGV). It was soon shown they were the same agent. The initials “GB” come from a surgeon in whose serum the virus was first isolated.

It is an RNA virus of the flavivirus family, distantly related to the hepatitis C virus, though it behaves very differently. Because the label “hepatitis G” proved misleading, current nomenclature calls it human pegivirus type 1 (HPgV-1). There is also a second human pegivirus (HPgV-2), likewise unable to cause disease.

Why does it not cause hepatitis?

The key lies in where the virus lives. Unlike the hepatitis C virus, human pegivirus does not replicate in liver cells (hepatocytes), but in immune cells such as lymphocytes. Because it does not infect the liver, it does not produce the inflammation that defines a hepatitis.

That is why, when this virus is detected, it comes without liver damage:

• It does not cause acute hepatitis with consequences.
• It does not produce chronic hepatitis.
• It has not been shown to lead to cirrhosis or liver cancer.

Some very old reports, especially from Japan, suggested a link with severe hepatitis, but later studies explained this by the multiple transfusions those patients received, not by the virus itself.

How is it transmitted and how common is it?

It is transmitted by parenteral routes, in a way similar to the hepatitis B and C viruses: transfusions, exposure to blood, sexual contact, and from mother to child during pregnancy or delivery. It is found worldwide, including in Chile.

In fact it is surprisingly common. An estimated 1 to 5% of healthy people carry the virus circulating in their blood, and a much larger share have had contact with it at some point. In most healthy people the virus clears on its own within one or two years.

Should it be tested for or treated?

No. Because it does not cause disease, there is no reason to order testing for it in routine blood work, and there is no treatment aimed at it. If it was detected for some reason, it does not require liver follow-up.

If your liver blood tests are abnormal, the cause must be looked for elsewhere (for example, fatty liver, hepatitis B or C, alcohol use or medications), not in this virus.

A scientific curiosity: its link with HIV

The most interesting thing about human pegivirus has nothing to do with the liver, but with HIV. Several studies observed that people with HIV who also carried this virus tended to live longer and to progress more slowly toward AIDS than those who did not.

The virus is thought to interfere with HIV replication and to modulate the immune response, reducing immune activation. It is a striking effect that remains under investigation, and has even prompted the idea of harnessing the virus for therapeutic purposes. For now it is a scientific curiosity, not an available treatment.

In short

If you were told about “hepatitis G,” you can rest easy: it is a name inherited from another era. This is a virus that can infect people but does not harm the liver and needs no treatment. Its main interest today is historical and scientific.

See also

• What is hepatitis?
• Types of hepatitis
• Hepatitis C
• Liver enzymes (ALT and AST)