When a genital herpes outbreak occurs, the virus can be cultured for about 11 days with an initial outbreak and for about 4 days with a recurrence. However, the virus can be found on the skin even in between outbreaks.
As it turns out, the herpes virus becomes active and can be “shed” from the skin on days when patients who have recurrences of genital HSV-2 feel perfectly well and in people who have only a positive blood test for HSV-2 and have never had an outbreak. In a pivotal study, women with symptomatic genital herpes Type 2 collected cultures from the cervix, vulva, and the rectum every day for over 3 months. They kept track of their symptoms with a daily diary, as well.
Shedding occurred without symptoms on 2% of the days in women with HSV-2 genital herpes. They shed more frequently in the 7 days prior to or following an outbreak. Shedding lasted fewer days when they were free of an outbreak but still accounted for one-third of all the days they shed the virus.
What about the 80% of people who are HSV-2 positive who are not aware they are infected? Samples from patients who had herpes type 2 but who had never had symptoms were compared to patients with genital HSV-2 who had symptoms in terms of shedding the herpes virus. The patients who had a history of symptoms shed the virus when they had no symptoms on 13% of days while those who only had HSV-2 by blood testing shed on 9% of days. What is interesting is that the amount of virus shed during when no symptoms were present was essentially the same in both groups.
The precise rate of genital HSV-1 shedding in between outbreaks is not known but it is suspected it is far less than genital HSV-2 herpes. One small study using cultures, and not the much more sensitive PCR test, found shedding on only 1 out of every 200 days. Unfortunately, we know that HSV-1 also sheds asymptomatically from the mouth and in developed countries like the US, it is responsible for most of the new infections of genital herpes.
Some things are associated with a risk for shedding and some things are not. With genital herpes, time of the month in relation to menstruation, sexual orientation, and sex were not. Having a history of prior outbreaks, especially a history of more than 8 outbreaks/year, and being Caucasian, are a risk for an increase in asymptomatic genital shedding, as well as an increase in overall shedding (Symptomatic and Asymptomatic shedding combined).
The bottom line is that people can shed the virus between outbreaks when they are feeling well and people who never get symptoms can also shed the virus.