What does a positive IgG for Hepatitis A indicate in a patient?

A positive IgG for Hepatitis A indicates that a patient has had a past infection with the Hepatitis A virus and has developed immunity as a result. This immune response is a hallmark of a previous exposure to the virus, whether from a natural infection or vaccination. IgG antibodies remain in the body long after the infection has resolved or after vaccination, providing long-term protection against future infections from the same virus.

In the context of Hepatitis A, this is particularly significant as the virus typically causes acute infections without leading to chronic disease. As such, the presence of IgG is indicative that the immune system has responded appropriately to the virus, equipping the individual with a level of immunity that can prevent reinfection. This is important for both public health and patient management, as those with a positive IgG status do not represent a current risk of transmission.

Understanding this concept helps clarify the meaning of serologic markers in infectious diseases and the immune response overall.