BOSTON — Genital herpes is a recurrent, lifelong viral disease. This is the one thing that patients and providers don't like to say, but there's no way around it, Laura J. Mulcahy said at a conference on contraceptive technology sponsored by Contemporary Forums.
Other difficult truths about infection with herpes simplex virus (HSV) type 2? The overwhelming majority of people infected with the virus don't know that they have it, and people with asymptomatic or unrecognized disease shed the virus intermittently in the genital tract, said Ms. Mulcahy, a certified family nurse practitioner who is assistant medical director of the STD Center for Excellence at Montefiore Medical Center in New York.
“When we ask patients prior to screening for HSV-2 if they have a history of genital herpes … about 90% of those who ultimately test positive for HSV-2 antibodies reported having no history or symptoms of the infection,” she said. This underrecognition can be attributed to the fact that the leading cause of HSV-2 infection is asymptomatic shedding of the virus.
“There is a misperception and some clinicians are still telling patients that the infection is spread only through [HSV-2] sores. This is absolutely not true. The virus can shed even when the skin looks normal, and that's when most infections occur,” she said.
Patient education about asymptomatic disease is critical to an effective screening protocol. Ms. Mulcahy stressed that patients who come in for STD screening are told that, “from this day forward, the fact that you or your partner have no symptoms means nothing; the fact that you and your partner look fine means nothing; and the fact that you or your partner had a negative screen 6 months ago, if you've had partners in the interim, means nothing.”
Another factor contributing to the high rate of unrecognized disease is that many patients who have been screened for STDs believe they have been tested for genital herpes. “A complete STD screen does not include testing for herpes. Many patients believe they are being tested for everything. If their STD screen is negative, they assume that means they don't have herpes,” said Ms. Mulcahy.
“Clinicians who don't routinely screen for herpes [as part of an STD screening protocol] must inform patients that they are not being tested and chart that in the patient record so there is no confusion,” she said.
If a patient asks to be screened for HSV-2, then several points need to be addressed before testing, Ms. Mulcahy stressed:
▸ The absence of symptoms does not predict a negative screen.
▸ In patients with lesions, a herpes culture has low sensitivity, especially as lesions heal. As such, a negative culture does not rule out HSV-2.
▸ In the event of a positive HSV-2 test in an asymptomatic person, it is not possible to determine how long the virus has been present, when or whether they will have outbreaks, or whether they will ever have a problem with herpes.
▸ In the event of a positive HSV-2 test, patients in some states have a legal obligation to inform current and future sexual partners of their infection status before genital to skin contact.
Counseling patients on these points before testing is imperative. “If you wait until after a positive screen, patients will no longer be listening. They must know what to expect before they hear the word positive,” she said.
Among the tools used to screen for HSV-2, clinical examination and history are insensitive and nonspecific. “Symptoms are easily confused with other conditions or may present atypically, for example, as redness rather than sores,” Ms. Mulcahy said. Viral culture is the most valid test available, despite the high rate of false negatives.
Polymerase chain reaction assays are another diagnostic option. They have increased sensitivity but are not approved by the Food and Drug Administration, nor are they available in all laboratories. Cellular detection methods, including Tzanck test and Pap smear, are not recommended for HSV detection because of their low sensitivity, she said.
Many type-specific serology tests, such as the older enzyme-lined immunoabsorbent assay tests, can result in false-positive results because of problems with cross reactivity. The newer type-specific HSV glycoprotein G1 (HSV-1) and G2 (HSV-2) tests are more reliable, but their sensitivities vary, she said, noting that a positive test should be confirmed with another test to reduce the risk of false-positive diagnoses. The Western blot is the reference standard serology test, but it is not approved and is only available from one laboratory at the University of Washington, Seattle.