Transmission

Transmitting the infection

People with herpes can be infectious either at the time of symptoms or sometimes when there are no symptoms present. People who experience an episode of herpes, either facial or genital, should consider themselves infectious from the first symptoms to the healing of the last lesion. Facial herpes lesions (cold sores) are also an important source of infection through oral sex and this should be avoided if one partner has a facial cold sore. People worry a great deal about transmitting genital infection, but are less concerned about facial herpes (cold sores).

People with no obvious lesions can still have infectious virus present at certain times through a process known as 'asymptomatic viral shedding'. This is inclusive of facial herpes and genital herpes. 

Occasionally one partner in a long-term relationship may develop symptoms of herpes for the first time. Often this is due to one or both of the partners being carriers of HSV and not knowing it. It does not necessarily imply recent transmission from someone outside the relationship.

By avoiding sex when the signs of herpes are present, and by using condoms with sexual partners between outbreaks, the change of passing on herpes is reduced. Taking daily oral antivirals, known as suppressive treatment, as well as using condoms, makes the chances of passing on herpes extremely low. 

It is highly unlikely that HSV will be passed on to other people by the sharing of towels or toilet seats. Outside the body the virus cannot survive for more than a few seconds. The virus is killed by the use of soap and water (please do not put soap on your genitals).

Viral shedding

When the HSV reactivates in the ganglion and travels down the nerve fibres to the skin surface, particles of virus may be ‘shed’ on the surface of the skin, with or without any signs or symptoms of infection present. This is called viral shedding. Viral shedding also occurs when blistering and/or sores are present. During these times, HSV may be transmitted to sexual partners.

There is no way to tell when the virus is being asymptomatically shed on the skin surface and therefore no way to predict when you may be infectious and at risk of transmitting the virus to a sexual partner. However, viral shedding is most prevalent just before, during and immediately after the presence of symptoms (sores); therefore sexual contact should be avoided during these times. Between outbreaks, viral shedding may still occur a very small percentage (approximately 1-5% of days per year) of the time (this is called asymptomatic viral shedding). Using condoms reduces the chance of transmission to sexual partners.

How genital herpes is spread

You can get genital herpes by having sexual contact (vaginal, oral or anal sex) with someone who carries HSV. It used to be believed that transmission (passing it on) only occurred if herpes blisters or sores were present. However, it is now known that transmission can occur when herpes blisters or sores are not present. This can occur in three situations:

• People who have recurrent genital herpes (repeated episodes) can transmit the virus between recurrences, through asymptomatic shedding. (Remember it is quite possible your partner/s may already carry one or both of the herpes simplex viruses. Once an individual has the virus they cannot be re-infected - however, for example, if they have HSV-1 facially they can still get HSV-1 genitally.)
• There are many people who are exposed to and infected by the virus but never develop any signs or symptoms of the infection. These people carry and may ‘shed’ the virus from time to time without showing symptoms and in doing so may transmit the infection to their sexual partner/s if they have sex at that time. Up to 75% of people get HSV from partners who have no signs and symptoms of HSV and are unaware they have the infection.
• People who know they have the virus but have only experienced one episode may still shed the virus asymptomatically on the skin.