Some people with herpes take antiviral drugs for years, while others just use them periodically -- for example, when they're starting a new relationship or anticipating a high-pressure situation. (Stress can up the risk of a herpes outbreak.) "It really is a very personal decision for patients, " Johnston says.
The trick to managing risk is not just seeing the thunderheads gathering this week or month, but also anticipating any potential nasty weather one, three or even five years from now.