Herpes spreads primarily through direct skin-to-skin contact with an infected person, and it can transmit even when no sores are visible. The virus passes through mucous membranes (the moist lining of the mouth, genitals, and rectum) and through breaks in the skin. There are two types: HSV-1, which typically causes oral herpes (cold sores), and HSV-2, which usually causes genital herpes. Both can infect either location, and both spread in similar ways.
Sexual Transmission
Vaginal, anal, and oral sex are the most common routes for genital herpes. You can get the virus through contact with a herpes sore, genital or oral fluids, saliva, or simply the skin in the genital or oral area of someone who is infected. One route that surprises many people: receiving oral sex from a partner with cold sores (HSV-1) can give you genital herpes. This has become an increasingly common cause of new genital herpes cases.
The per-act risk of transmission varies by direction. In one large study, for every 10,000 acts of vaginal or anal intercourse, about 8.9 women acquired HSV-2 from a male partner, while only 1.5 men acquired it from a female partner. That roughly sixfold difference likely reflects anatomical factors: mucous membrane exposure is greater in women during intercourse. The risk per individual encounter is low, but it accumulates over time in an ongoing sexual relationship.
Asymptomatic Shedding
This is the part that makes herpes so difficult to contain. The virus periodically reactivates and appears on the skin surface without causing any noticeable symptoms. A person shedding the virus asymptomatically looks and feels completely fine, yet can still transmit herpes to a partner. Most people with genital herpes are unaware they carry it, and most new infections come from partners who don’t know they’re shedding.
The frequency of this invisible shedding depends on the virus type. HSV-2 sheds on roughly 34% of days in the first year after infection and still about 17% of days a decade later. HSV-1 genital infections shed far less: around 12% of days at two months, dropping to 7% by eleven months, and falling further to about 1.3% of days by two years in people who initially shed frequently. In most instances, people shedding virus had no symptoms at all. This difference in shedding frequency is a major reason HSV-2 genital infections recur and transmit more often than HSV-1 genital infections.
Non-Sexual Skin Contact and Shared Objects
Oral herpes (cold sores) commonly spreads through kissing, including casual kissing between family members and children. This is how most people acquire HSV-1, often in childhood. Sharing utensils, washcloths, or lip balm with someone who has an active cold sore also poses a risk, though transmission through objects is less efficient than direct skin contact because the virus doesn’t survive long on surfaces. The practical advice: avoid sharing these items when cold sores are present.
Herpes does not spread through toilet seats, swimming pools, or casual contact like handshakes. The virus is fragile outside the body and needs direct contact with mucous membranes or broken skin to establish infection.
Spreading It to Other Parts of Your Own Body
It’s possible to transfer the virus from one area of your body to another, a process called autoinoculation. For example, touching an active cold sore and then rubbing your eye could potentially lead to a herpes eye infection, which can be serious. Touching a genital sore and then your face carries the same risk. However, once your immune system has built antibodies to the virus (which happens within the first few weeks to months of infection), this self-transfer becomes much less likely. Autoinoculation is mostly a concern during a first outbreak, before your body has mounted a full immune response. Washing your hands after touching a sore is a simple and effective precaution.
Transmission During Childbirth
A mother with genital herpes can pass the virus to her baby during vaginal delivery, and the risk depends heavily on timing. If a woman contracts herpes for the first time near the end of pregnancy, the transmission rate to the newborn can be as high as 60%. That’s because her body hasn’t yet produced antibodies that would partially protect the baby. For women who had herpes before pregnancy and experience a recurrence at delivery, the risk drops dramatically to less than 2%, thanks to lower viral loads and protective antibodies that cross the placenta.
Neonatal herpes is rare but serious. When doctors know a mother has active genital lesions at the time of delivery, a cesarean section is typically recommended to reduce the baby’s exposure to the virus.
Reducing the Risk of Transmission
Condoms lower the risk but don’t eliminate it. In one study, 8% of people who never used condoms acquired HSV-2 over the study period, compared with 4.6% of those who used condoms more than 75% of the time. That’s a meaningful reduction, but herpes sores and viral shedding can occur on skin that a condom doesn’t cover, like the thighs, buttocks, or the base of the genitals.
Daily suppressive antiviral therapy taken by the infected partner reduces HSV-2 transmission to an uninfected heterosexual partner. Combining daily antivirals with consistent condom use provides the greatest protection. Avoiding sexual contact during outbreaks, when viral shedding is highest, further reduces risk. None of these strategies makes transmission impossible, but layering them together brings the odds down substantially.
Knowing your status matters. Because most transmission happens from people who don’t realize they carry the virus, getting tested and having open conversations with partners gives both people the information they need to make decisions about risk.