The Link Between Herpes Simplex Virus (HSV) and HIV

Herpes simplex virus (HSV) is a common cause of ulcerative skin disease in both immune-compromised and immune-competent individuals. Infection can be caused by either HSV type 1 (HSV-1) or HSV type 2 (HSV-2) and can present as either oral herpes (a.k.a. cold sores or fever blisters) or genital herpes (commonly referred to as herpes).

HSV is contagious and you can catch it by direct contact with an exposed sore or the body fluid of an infected individual. Sometimes a person can catch it even when there are no visible signs. Protective barriers in the form of condoms or dental dams can reduce the risk of transmission; however, the infection can occur on parts of the body not readily covered by a condom.

Today, genital herpes is one of the most common sexually transmitted diseases, with an estimated 775,000 new infections in the U.S. each year. Of these, 80% are fully unaware that they are infected.

Man's lip with herpes lesion
Mohd Akhir / EyeEm / Getty Images

HSV Infection and Symptoms

HSV-1 is usually acquired during childhood and had been traditionally associated with oral herpes, while HSV-2 is sexually transmitted and primarily affects the anogenital region between the anus and genitals.

Most individuals infected with HSV have either no symptoms or mild symptoms that initially go unnoticed. When symptoms do appear, they initially present with tingling and/or redness, followed by blister-like lesions that rapidly merge into open, weeping sores. The sores are often quite painful and can be accompanied by a fever and swollen lymph glands.

  • Oral herpes generally causes sores around the mouth and sometimes on the mucosal tissue of the gums.
  • Genital herpes is most commonly noted on the penis, inner thigh, buttocks, and anus of males, while lesions mostly appear on the clitoris, pubis, vulva, buttocks, and anus of females.

Genital infections with HSV-1 occur due to oral-genital sex practices. In fact, studies now indicate that anywhere from 32% to 47% of genital herpes is caused by HSV-1.

Symptom Patterns

Both oral and genital herpes cycle between periods of active disease, which can last from two days to three weeks, followed by a period of remission.

After the initial infection, the viruses attach themselves to sensory nerve cells, where they remain for a lifetime. HSV can reactivate at any time, sometimes due to triggers. The frequency and severity of outbreaks tend to subside over time. 


Diagnosis is generally made by clinical examination of the visible signs. Sometimes genital herpes is often difficult to diagnose because symptoms can be mild and easily confused with other conditions, such as urethritis or fungal infection.

Laboratory tests are sometimes used to make a definitive diagnosis, including newer generation HSV antibody tests which can identify HSV-1 or HSV-2 with greater than 98% specificity. These tests cannot detect new infections because it takes time for the body to make antibodies to the virus.

The Link Between HSV and HIV

People who have a compromised immune system, such as HIV infection, have a higher frequency of HSV outbreaks that can be severe, spreading from the mouth or genitals to deeper tissues in the lungs or brain. As such, HSV has been classified as an "AIDS-defining condition" in people with HIV if it lasts longer than a month or if it affects the lungs, bronchi, or esophagus. 

There is also increasing evidence that HIV transmission is substantially linked to HSV-2. Current research suggests that an active HSV-2 infection, whether symptomatic or asymptomatic, can increase the release of HIV from mucosal tissues in a process called "viral shedding." As a result of such shedding, people with an undetectable HIV viral load may, in fact, have detectable viral activity in genital secretions.

While the use of combination antiretroviral therapy (cART) is known to decrease the incidence of symptomatic HSV, it doesn’t necessarily reduce HIV shedding. As a result, HIV-positive individuals with active HSV-2 infection are three to four times more likely to transmit HIV to a sexual partner.

Similarly, HIV-negative people with active HSV-2 infection are at increased risk of acquiring HIV.

There are several reasons for this:

  • Open sores provide easier access for HIV
  • HIV actively binds to macrophages (a type of immune cell) found at sites of active infection

These factors mean that HIV can effectively carry through the mucosal barrier of the vagina or anus directly into the bloodstream.

Treatment and Prevention of Herpes

There is currently no cure for either HSV-1 or HSV-2. Antiviral drugs may be used to treat HSV, often requiring higher doses for people with HIV, but is only recommended for those who experience outbreaks.

The oral pill form antivirals predominantly used to treat HSV are:

The drugs may be administered intermittently (upon initial infection or during flare-ups) or as ongoing, suppressive therapy for those with more frequent outbreaks. Most drug side effects are considered mild and include headaches, diarrhea, nausea, and body aches being among the most commonly noted.

Severe cases may be treated with intravenous acyclovir.

Suppressive HSV therapy may reduce the risk of HSV transmission by approximately 50%, particularly with consistent condom use. While suppressive HSV therapy has not been shown to reduce the risk of HIV, one study showed that the daily use of oral acyclovir is associated with a lower HIV viral load and a lower appearance of genital ulcers.

In order to reduce the risk of acquiring or transmitting HIV if you have HSV:

  • Use condoms during vaginal, anal, and oral sex.
  • Reduce your number of sex partners.
  • Abstain from sex during herpes outbreaks.
  • Get tested regularly for HIV and other sexually transmitted infections.
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By James Myhre & Dennis Sifris, MD
Dennis Sifris, MD, is an HIV specialist and Medical Director of LifeSense Disease Management. James Myhre is an American journalist and HIV educator.