[1][2] Herpes simplex virus 2 can be divided into two clades: one is globally distributed and the other is mostly limited to sub Saharan Africa.

In one study, daily genital swab samples found Herpes simplex virus 2 at a median of 12–28% of days among those who have had an outbreak, and 10% of days among those suffering from asymptomatic infection, with many of these episodes occurring without visible outbreak ("subclinical shedding").

[7] In another study, 73 subjects were randomized to receive valaciclovir 1 g daily or placebo for 60 days each in a two-way crossover design.

A daily swab of the genital area was self-collected for Herpes simplex virus 2 detection by polymerase chain reaction, to compare the effect of valaciclovir versus placebo on asymptomatic viral shedding in immunocompetent, seropositive subjects without a history of symptomatic genital herpes infection.

[7] Studies on discordant partners (one infected, one not) show that the transmission rate is approximately 5 per 10,000 sexual contacts.