A patient who has herpes genitalis receives a prescription for acyclovir (Zovirax). Which criterion should the nurse use to determine whether the antiviral therapy is effective?

Acyclovir (Zovirax) is an antiviral medication that works by inhibiting viral DNA polymerase, thereby suppressing herpes simplex virus replication. Because herpes genitalis is a lifelong latent infection, acyclovir does not eradicate the virus from the body and will not render the patient seronegative — herpes antibodies remain detectable in blood throughout life. The therapeutic goals of acyclovir are to decrease the frequency, severity, and duration of outbreaks. Therefore, the appropriate criterion for evaluating effectiveness is a lower incidence of herpetic lesions, whether the patient is using suppressive therapy or episodic treatment. Seronegativity is not an achievable or appropriate outcome because the virus persists in sensory ganglia and antibody production continues; this rules out the first option. Shortening of latent periods implies that outbreaks would occur more often, which is the opposite of the desired outcome and therefore incorrect. Appearance of secondary infections would indicate reduced immune function or treatment failure, making it an adverse rather than a therapeutic indicator. Monitoring for reduced frequency and severity of genital lesions is the clinically correct measure of antiviral efficacy.