Herpes Simplex

Description

Alternative Names

Risk Factors

Everyone is at risk for herpes simplex virus. In fact, HSV-1 infects more than 85% of the world's population, although the risk varies by region. Still, a national survey that analyzed data from 1988 to 1994 found that 73% of Americans over 12 years old have evidence of infection with either form of the herpes virus. Just over half were infected only with HSV-1, 5% only with HSV-2, and almost 17% with both. Infection is lifelong, so once a person is infected he or she remains infected. Studies are mixed on whether being infected with HSV-1 protects against subsequent infection with HSV-2, although evidence indicates that prior infection with HSV-1 may result in milder initial outbreaks of HSV-2.

Individuals at Risk for Oral Herpes

Oral herpes is usually caused by HSV-1, which is easily transmitted and is the most common form of the herpes simplex virus. Most people with HSV-1 infection were first infected during childhood, with the highest incidence of first infection occurring between six months and three years of age. The incidence in children varies among regions and countries, with the highest rates occurring in crowded and unsanitary regions. Studies suggest that by age five more than a third of children in low-income areas are infected compared to 20% of children in middle-income areas. However, by the time this more privileged group reaches their thirties, about 60% have become infected with HSV-1. After age 40, socioeconomic differences in infection rates become even less pronounced.

Individuals at Risk for Genital Herpes

Some experts estimate there are about 60 million cases of genital herpes in the US. In one study of sexually active adults, 5.1% developed herpes each year, although the incidence varies widely depending on the degree of sexual activity. Among monogamous heterosexual couples, for example, when one partner is infected with HSV-2, the risk to the other is about 10% per year, with a noninfected woman having a higher risk than a noninfected male. Less than 1% of American children younger than 15 have genital herpes. In such cases, sexual abuse should be considered.

It should be noted that HSV-1 is becoming a major cause of genital herpes as well, and in some studies it is now an even more common cause than HSV-2. Using only statistics on HSV-2 infection, then, may underestimate the actual prevalence of genital herpes.

Gender. Anyone who is sexually active is at risk for genital herpes, and it is on the rise. Studies indicate that around 22% of Americans are infected with HSV-2, with the risk higher in women (26%) than in men (18%). Men, however, have twice as many recurrent infections as women.

Women have an 80% to 90% chance of contracting HSV-2 after unprotected sexual activity with an infected partner and are four times more likely to be infected than men. In one study of sexually active American adolescents, 15% of the females had evidence of being infected with HSV-2, compared to none of the males. Having a drinking problem greatly increased the likelihood of infection in these young women.

Ethnicity. Although African Americans are more likely to test positively for HSV-2, Caucasians have a higher risk for active genital symptoms, and over the past few years the greatest increase in HSV-2 has been observed in white adolescents.

Compromised Immune Systems. People with compromised immune systems, notably patients with HIV, the virus that causes AIDS, are at very high risk for HSV-2. Between 68% and 81% of patients with HIV are infected with HSV-2. Such patients are also at risk for more severe complications from herpes. Other immunocompromised patients include those taking drugs that suppress the immune system and transplant patients.

Individuals at Risk for Specific Forms of Herpes

The following are examples of groups that are at particularly risk for specific forms of herpes:

• Healthcare professionals, including physicians, nurses, and dentists. This group is at higher than average risk for herpetic whitlow, which is herpes that occurs in the fingers.
• Wrestlers, rugby players, and other athletes who participate in direct contact sports without protective clothing. These individuals are at risk for herpes gladiatorum, an unusual form of HSV-1 that is spread by skin contact with exposed herpes sores and usually affects the head or eyes.