Herpes transmission and safe sex
People with genital herpes or cold sores can pass these conditions on to their sexual partners. It’s possible to decrease the risk of passing it on, but unfortunately it’s not as straightforward to prevent transmission as it is for other sexually transmitted infections (STIs) like chlamydia or HIV.
Safe sex tips
Some of the strategies that work well to prevent other sexually transmitted infections don’t work as well for genital herpes, because:
- Most people with herpes don’t know they have it. That means they don’t even know that they might be passing it on to their partners.
- Even people who know they have herpes or cold sores can be infectious in between outbreaks. The risk is less, but on some days, most people with herpes or cold sores release the virus from the skin—even when there’s no sign of an outbreak. The herpes virus is released from the region where herpes sores appear. This is called asymptomatic shedding. It’s the most common way of transmitting herpes or cold sores because you can’t tell when it’s happening.
- Condoms or other barriers such as dental dams can help reduce the risk of passing on the herpes virus, but they aren’t 100 per cent effective.
How herpes is transmitted
It’s helpful to have some knowledge of how herpes simplex virus—which causes both genital herpes and cold sores—is transmitted. Once you know how it works, you can understand how to reduce the risk.
The herpes simplex virus (HSV) is passed on from one person to another by skin-to-skin contact. The virus rubs off the skin of one person and into the skin of another. This happens most easily if:
- The contact is very firm and/or for a long period of time
- The skin of the person “receiving” the HSV is very soft, tender or damaged in some way.
This explains why herpes simplex is transmitted fairly easily through intercourse, oral sex or kissing. During these activities, parts of the body that shed HSV get rubbed against the parts of the body that are most easily able to receive it. It also helps explain why people don’t usually get herpes on other parts of the body.
Can you give herpes to someone who already has it?
Remember that most people carrying HSV don’t know they have it. They may never have developed any symptoms or maybe they mistook the symptoms for something else, like thrush or a skin rash.
Recent research has shown us that:
- About 12 per cent of Australians are carrying HSV-2 (the commonest cause of genital herpes)
- About 76 per cent of Australians are carrying HSV-1 (which usually causes cold sores but also causes about 40 per cent of genital herpes)
If you have genital herpes and your partner has never had an outbreak, they could still be carrying one or both strains of HSV and be unaware of it. In this situation, it’s harder for you to pass on HSV to your partner, as their immune system will recognise it and stop it from entering their body again. Even if you have HSV-2 and they only have HSV-1, they will still get some protection from their immune system. They might get the virus from you, but the chances are they won’t ever get a serious outbreak. This is reassuring news, as most people already have HSV-1.
The herpes blood test: type-specific serology
Many couples where one partner has herpes choose to have a blood test (type-specific HSV serology) to learn whether the other partner is at risk. Reasons for having this test include:
- Long-term relationships where the couple is considering relaxing their safer sex activities
- Where a woman with no history of herpes is planning to fall pregnant. (If there’s no evidence of herpes, she will need to be very careful not to get the virus from her partner during the pregnancy as it can be dangerous for the baby.)
If both partners test positive for the same strain of HSV, it’s unlikely one partner could pass it to the other and they would normally not need to take any precautions to prevent transmission.
If one partner has HSV-1 and/or HSV-2 and the other doesn’t, the couple is said to be serodiscordant. The negative partner is potentially at risk of getting HSV from the positive partner and the couple may choose to reduce the risk of transmission in various ways.
Risk Behaviour - Rating the risks
With herpes transmission, it’s better to think of the risks along a scale, rather than simply “safe” or “not safe”. The following charts can help you decide which things you’d like to do to reduce the risk of transmitting HSV. This information is more relevant to couples who are serodiscordant or haven’t had type-specific serology.
Cold sores/Oral herpes
| Activity | Risks | Why |
|---|---|---|
|
Closed-mouth “dry” kissing |
High risk of passing on HSV-1 to children |
Young children who’ve never come into contact with HSV are at risk if they are kissed by relatives or friends—even those who’ve never had cold sores. Most Australians carrying HSV-1 were infected in this way as children. |
|
French kissing (“tongue kissing”) |
High risk of passing on HSV-1 |
Adults who’ve never come into contact with HSV-1 can easily contract it from French kissing. |
|
Oral sex |
Very low risk of contracting cold sores |
If your partner has genital herpes and you give them oral sex (ie “go down” on them) there is very little chance of contracting cold sores. This seems to be because HSV-2 survives much better on or near the genitals than the lips. |
Genital herpes
| Activity | Risks | Why | ||
|---|---|---|---|---|
|
Non-genital massage |
Virtually no risk |
Massaging your partner’s body with your hands will not transmit herpes from your genitals or lips |
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|
Mutual masturbation (“hand job, fingering” etc) |
Virtually no risk |
Masturbating your partner with your hands will not transmit the herpes virus from your genital or lips |
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|
Sharing sex toys (eg vibrators, dildos, etc) |
Moderate risk |
HSV might be able to survive briefly on a sex toy after it’s used. Also, the toy may carry blood or genital secretions which carry other STIs. It always safest to use your own. |
||
| Oral sex |
No cold sores or other symptoms |
Low risk |
If there are no symptoms, it’s safe most of the time. However, on some days, HSV-1 will be transmitted from the lips even when there are no symptoms. This is a very common way of transmitting HSV-1 to the genitals. |
|
|
Active outbreak of cold sores |
High risk |
If there are cold sores, then HSV-1 will be present (and also for a few days before the cold sores appear). It can easily rub into your partner’s skin during oral sex. |
||
| Vaginal or anal sex |
No sores or other symptoms |
Using a condom or barrier |
Very low risk |
If there are no symptoms, it’s safe most of the time. However, on some days, HSV-1 or 2 will come off the genitals even when there are no symptoms. Remember that the virus is passed on by skin-to-skin contact, so any areas of skin that aren’t separated by the condom or other barrier might be at risk. |
|
No condom or barrier |
Low risk |
Again, if there are no symptoms, it’s usually safe. But with no condom or other barrier, there’s no protection against asymptomatic shedding so the risk is a little higher than with a condom. |
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|
Active outbreak of genital herpes |
Using a condom or barrier |
High risk |
If a herpes outbreak is present, the virus is being released. A condom or other barrier will prevent the virus from being rubbed in to any area covered by the condom or barrier. There are male and female condoms, most condoms you buy are male condoms, i.e. they cover the shaft of the penis only. Unfortunately these condoms aren’t foolproof, as it’s very common for the virus to shed from more than one place without you being aware of it. |
|
|
No condom or barrier |
Very high risk |
There is a very high chance of HSV-1 or HSV-2 being rubbed into the partner’s skin during the friction of intercourse. |
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