What does serology typically indicate for a previous Hepatitis A infection or immunity from vaccination?

The presence of positive HAV IgG in combination with a negative HAV IgM indicates either a past infection with Hepatitis A or immunity resulting from vaccination. Specifically, HAV IgG antibodies develop in response to an infection or vaccination and persist in the body, providing long-term immunity. On the other hand, HAV IgM antibodies are present during an active, acute infection. Therefore, having negative HAV IgM confirms that there is no current infection, while the positive HAV IgG signifies that the individual has either recovered from a previous infection or has been vaccinated, hence showing immunity.

This interpretation aligns with standard serological testing practices for Hepatitis A, where the detection of IgM and IgG antibodies helps to delineate between acute and past infection or vaccination status.