Herpes spreads through direct skin-to-skin contact, most often during kissing, oral sex, or genital sex. The virus needs to reach a mucosal surface (like the lips, genitals, or inside of the mouth) or a tiny break in the skin to establish an infection. What makes herpes particularly easy to transmit is that the person passing it on frequently has no visible sores at the time.
How the Virus Enters Your Body
Herpes simplex virus exists in two types. HSV-1 typically causes oral herpes (cold sores), while HSV-2 is the more common cause of genital herpes, though either type can infect either location. Both types spread the same way: the virus in one person’s skin or saliva makes contact with a mucosal surface or microscopic abrasion on another person’s body. These tiny skin breaks are often invisible to the naked eye, which is why transmission can happen even when the skin looks perfectly healthy.
Once the virus reaches a new host, it replicates at the initial site of contact, then travels along nerve fibers to clusters of nerve cells near the spine called ganglia. There, it establishes a lifelong latent infection, periodically reactivating and traveling back to the skin surface. This cycle of dormancy and reactivation is what makes herpes a recurring infection and what enables ongoing transmission over months and years.
Asymptomatic Shedding: Spreading Without Symptoms
Most people picture herpes transmission as happening during an active outbreak, with visible blisters or sores present. In reality, the virus frequently reaches the skin surface without producing any noticeable symptoms. This is called asymptomatic or subclinical shedding, and it accounts for a significant share of new infections.
For HSV-2, shedding rates are highest in the first year after infection, occurring on roughly 26% of days. That rate drops to about 13% of days between years one and nine, and to around 9% of days after a decade. Even years after the initial infection, the virus periodically surfaces without warning. Shedding can occur across a wide area of the genitals, buttocks, thighs, and rectum, not just at the spot where sores typically appear. Detailed swabbing studies have shown that the virus can show up at a single small site or flash across the entire genital region at once.
This means a person who hasn’t had a visible outbreak in months or even years can still pass the virus to a partner on any given day.
Sexual Transmission Routes
Genital-to-genital contact during vaginal or anal sex is the most commonly recognized route for HSV-2 transmission. But oral sex is an increasingly important pathway, particularly for HSV-1. More than 85% of new genital HSV-1 infections result from oral-to-genital contact rather than genital-to-genital sex. Someone with a history of cold sores (or a recent, invisible oral shedding episode) can transmit HSV-1 to a partner’s genitals during oral sex.
This has reshaped the landscape of genital herpes. As fewer people acquire oral HSV-1 in childhood, more adults encounter the virus for the first time through sexual contact, making them susceptible to genital infection. HSV-1 now causes a substantial and growing proportion of genital herpes cases in many countries.
Transmission During Childbirth
A pregnant person with genital herpes can pass the virus to their baby during vaginal delivery. The risk depends heavily on timing. A first-ever genital herpes infection acquired near the time of delivery carries a transmission risk of about 57%, because the body hasn’t yet developed antibodies that can offer the baby partial protection. For someone who has had recurrent genital herpes before pregnancy, the risk drops dramatically to around 2%.
Neonatal herpes, while rare, is serious. This is why obstetric teams screen for active lesions near delivery and may recommend a cesarean section if sores are present.
Can You Catch Herpes From Objects or Surfaces?
Herpes is fragile outside the body, but not instantly destroyed. In laboratory conditions, the virus from active cold sores survived up to two hours on skin, three hours on cloth, and four hours on plastic surfaces. In practical terms, this means transmission from shared towels, razors, or lip balm is theoretically possible but far less efficient than direct contact. The virus needs a sufficient quantity and a vulnerable entry point, both of which are harder to achieve through objects.
Toilet seats, doorknobs, and swimming pools are not realistic transmission risks for adults. The concern is slightly higher for newborns, whose skin is more fragile and whose immune systems are immature. Adults with active cold sores should avoid sharing items that contact the mouth or face with infants.
Where on the Body Shedding Occurs
One common misconception is that herpes only sheds from the exact spot where sores appear. The virus actually lives in nerve ganglia that serve a broad area of skin. For genital herpes, that means shedding can occur anywhere in the zone served by the sacral nerves: the vulva, penis, perineum, perianal area, buttocks, and upper thighs. Recurrent outbreaks can appear at different sites within this region from one episode to the next.
For oral herpes, shedding occurs primarily on and around the lips and inside the mouth, including the gums and tongue. This is why kissing is the primary transmission route for oral HSV-1, even when no cold sore is visible.
How Condoms Reduce the Risk
Condoms lower the chance of transmission but don’t eliminate it, because herpes can shed from skin that a condom doesn’t cover. Their effectiveness also differs by direction. One large study found condoms reduced per-act HSV-2 transmission from men to women by 96%, but only by about 65% from women to men. The difference likely reflects the larger area of exposed genital skin in women, which a male condom doesn’t protect.
Daily antiviral medication taken by the infected partner further reduces transmission risk, and the two strategies combined offer the strongest protection outside of abstaining from contact during outbreaks. Avoiding sexual contact when sores, tingling, or burning sensations are present also helps, since viral load is highest during active outbreaks. Still, because asymptomatic shedding is common, no combination of precautions reduces the risk to zero.