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 present as oral herpes (a.k.a. cold sores or fever blisters) or genital herpes (commonly referred to as herpes).

HSV is most readily transmitted by direct contact with an exposed sore or the body fluid of an infected individual, although infection can occur 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. However, in recent decades, genital infections with HSV-1 have become common, likely 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.

Most individuals infected with HSV have either no symptoms or mild symptoms that 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 presents 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.

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 (and as a result of any number of potential triggers), although the frequency and severity of outbreaks tend to subside over time. 

Diagnosis is generally made by clinical examination of the patient, although genital herpes is often difficult to diagnose as symptoms can be mild and easily confused with other conditions (such as urethritis or a 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, but cannot detect new infections, as antibodies to the virus have not yet been made.

The Link Between HSV and HIV

In immune-compromised people, as in those with HIV, the frequency and symptoms of HSV outbreaks can sometimes 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 lasting longer than a month or presenting in 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, persons 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 persons with active HSV-2 infection are at increased risk of acquiring HIV. This is not only because open sores provide easier access for HIV, but because HIV actively binds to macrophages found in concentration at sites of active infection. In doing so, 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. The drugs may be administered intermittently (upon initial infection or during flare-ups) or as on-going, suppressive therapy for those with more frequent outbreaks.

The three antivirals predominantly used to treat HSV are Zovirax (acyclovir), Valtrex (valacyclovir), and Famvir (famciclovir). These are administered in oral pill form, although severe cases may be treated with intravenous acyclovir. Most drug side effects are considered mild, with a headache, diarrhea, nausea, and body aches being among the most commonly noted.

Suppressive HSV therapy may reduce the risk of HSV transmission by some 50%, particularly with consistent condom use. While suppressive 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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