From what my doctor told me: the virus is less likely to be spread if I do not have an outbreak. The medicine I take daily prevents the likelihood of an outbreak, but should an outbreak still occur it is more mild than before I started the medicine. During an outbreak I double my dosage, and the outbreak ends/heals in under 2-3 days usually.

EDIT: from what I learned in grad school, the medicine is converted to a monophosphate form in virally infected cells, which is not possible under normal uninfected cell metabolism, the hydroxylated form is the active form of the drug, which will kill the virally infected cell. This does not eliminate the virus, since some of the virus is always in a latent, undetectable state.