Get up to speed on genital herpes
Executive Summary
The Centers for Disease Control and Prevention has just issued updated resources for genital herpes clinical training. At least one in six adolescents and adults in the United States are infected with herpes simplex virus type 2 (HSV-2), with an estimated 776,000 new cases occurring each year. • Patients should be counseled that HSV can be transmitted when sores are not present, and most cases are transmitted during asymptomatic periods. Research indicates that disclosure of infection status to partners can reduce the transmission rate.
• Science is eyeing several therapeutic vaccines for genital herpes; three companies have vaccines in U.S. clinical trials.
It’s time to refresh your knowledge base on genital herpes. At least one in six adolescents and adults in the United States are infected with herpes simplex virus type 2 (HSV-2), with an estimated 776,000 new cases occurring each year.1 A chronic viral infection, most cases of recurrent genital herpes in the United States are caused by HSV-2. However, an increasing proportion of anogenital herpetic infection in some populations has been attributed to HSV-1 infection, according to the Centers for Disease Control and Prevention (CDC). There currently is no cure for the infection.
The CDC has just issued updated resources for genital herpes clinical training. (A self-study module for clinicians can be found at http://1.usa.gov/1fXcwvi. A ready-to-use curriculum, including a slide presentation, a student handout, case studies, and more are available at http://1.usa.gov/1uNDkm6.)
While there are no simple solutions for preventing herpes, there are steps everyone can take to reduce the spread of the disease, says Robyn Neblett Fanfair, MD, MPH, medical officer of the CDC’s Division of Sexually Transmitted Disease (STD) Prevention. It is critical to enhance awareness of possible prevention options, especially among youth before they are infected and among affected populations, notes Fanfair. Healthcare providers, specifically, play an important role in the prevention of genital herpes, she states.
Messages are critical
Fanfair says it is imperative that individuals with herpes be counseled about transmission and prevention of the disease. (Use a CDC brochure for patient education; go to http://1.usa.gov/QrICmC, and select "Genital Herpes." The brochure is available in English and Spanish.)
"There is not a cure for genital herpes; however, providers should speak with their patients about available and effective treatment options that help manage the disease and protect the health of sexual partners," states Fanfair. "In fact, daily therapy can reduce the risk of transmission by about 50%."
Patients should be counseled that HSV can be transmitted when sores are not present, and most cases are transmitted during asymptomatic periods, states Fanfair. Research also shows that disclosure to partners can reduce the transmission rate,2 so it is important that healthcare providers encourage patients to inform current and future sexual partners about their diagnosis, says Fanfair. Patients also should abstain from sexual activity during outbreaks (when sores begin to appear or are present), because of the likely increased risk of transmission, says Fanfair.
How to prevent herpes?
Prevention remains key for those who are not infected or who are unaware of their status. Providers should discuss STDs, including genital herpes, with their patients and ensure they understand what places them at risk and how to protect themselves, says Fanfair. It also is important that individuals talk openly with sexual partners, ask whether they have been diagnosed with genital herpes, and avoid sexual contact with individuals who have visible sores, she states.
"Regardless of infection status, general risk reduction strategies are important. Patients need to know that the surest ways to prevent infection are abstinence or mutual monogamy with a partner," Fanfair comments. "Reducing their number of sexual partners also can be helpful."
Be sure patients understand correct condom use. Because the HSV virus can be transmitted even when sores are not present, routine use of latex condoms consistently and correctly during oral, anal, or vaginal sex with partners of unknown infection status can reduce the chances of infection, states Fanfair.
Vaccines in view?
Science is eyeing several therapeutic vaccines for genital herpes, reports Anna Wald, MD, MPH professor of medicine at the University of Washington
Three companies have vaccines in United States clinical trials:
• Lexington, MA-based Agenus is developing its HerpV recombinant therapeutic vaccine for the treatment of genital herpes caused by HSV-2. In a Phase 2 study testing the biological efficacy of HerpV measuring genital viral shedding 45 days before and after three injections of HerpV, primary analysis, (which looked at viral shedding after the initial three injections) shows that subjects who received HerpV had a statistically significant reduction in viral shedding (P = 0.015; relative risk = 0.85). These results suggest a 15% reduction in viral shedding after the initial treatment period before the administration of the booster injection. The results also demonstrate a reduction in viral load of 34% (P = 0.08). Placebo patients showed no reduction compared to baseline in either parameter.3
• Genocea Biosciences of Cambridge, MA, is developing its first-in-class, investigational, protein subunit vaccine, GEN-003. In data presented at the 2013 Interscience Conference on Antimicrobial Agents and Chemotherapy, findings indicate that patients who received three doses of GEN-003 had reductions in the frequency of viral shedding of up to 51% (p < 0.001).4 Patients who received a placebo had no decline in viral shedding. Findings suggest T cell immune responses increased more than twentyfold to one vaccine antigen (ICP4) and more than tenfold to the other (gD2). In addition, GEN-003 increased neutralizing antibodies to the HSV-2 virus fivefold, on average, compared to baseline values.4
• Vical of San Diego is enrolling patients in its Phase 1/2 trial of its Vaxfectin HSV-2 vaccine. A total of 156 patients are scheduled to be enrolled in the randomized, double-blind, placebo-controlled trial to evaluate safety, tolerability, and efficacy in otherwise healthy HSV-2-infected patients ages 18-50 years at seven U.S. clinical sites.5
- Centers for Disease Control and Prevention. Genital herpes. CDC fact sheet. Accessed at http://www.cdc.gov/std/herpes/stdfact-herpes.htm.
- Wald A, Krantz E, Selke S, et al. Knowledge of partners’ genital herpes protects against herpes simplex virus type 2 acquisition. J Infect Dis 2006;194(1):42-52.
- Agenus Inc. Agenus’ HerpV therapeutic vaccine for genital herpes meets primary endpoint in randomized phase 2 trial. Press release. Accessed at http://bit.ly/1jsGd7l.
- A Wald, D Bernstein, K Fife. Novel therapeutic vaccine for genital herpes reduces genital HSV-2 shedding. 53rd Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC 2013). Denver, Sept. 10-13, 2013.
- Vical. Vical reports first quarter 2014 financial results and progress in key development programs. Press release. Accessed at http://bit.ly/QrRUPy.
