What type of virus does lamivudine primarily target?

Lamivudine is an antiviral medication that primarily targets both Hepatitis B virus (HBV) and Human Immunodeficiency Virus (HIV). It is a nucleoside analogue reverse transcriptase inhibitor, which means it works by inhibiting the reverse transcriptase enzyme necessary for viral replication. In the context of HIV treatment, lamivudine is used as part of a combination therapy to reduce the viral load in infected individuals, enhancing immune function and reducing the progression of the disease.

Similarly, in the case of Hepatitis B, lamivudine helps to lower the amount of virus in the body, thus preventing liver damage and complications associated with chronic Hepatitis B infection. Its effectiveness against both viruses is a significant aspect of its clinical use; therefore, it is classified primarily as targeting these two viruses.

This unique capability distinguishes lamivudine from other antiviral agents that may be specific to a particular virus in the other provided options.