Clinical Manifestations and Sequelae
Types of Infection
In genital herpes infection, the severity and frequency of clinical manifestations and the recurrence rate are influenced by viral and host factors. These factors include viral type, prior immunity to autologous or heterologous virus, gender, and immune status of the host.
There are several types of infection:
- First clinical episode refers to the initial symptomatic occurrence. The first clinical episode can be the result of a primary or non-primary infection with HSV-1 or HSV-2, or it can occur following an asymptomatic primary HSV-2 infection.
- Primary infection is defined as
the first infection ever with either HSV-1 or HSV-2.
No serum antibody is present when symptoms appear.
The disease is more severe than in recurrent
disease. Serum antibody may take several weeks to a
few months to appear.
- Non-primary infection is defined as newly acquired infection with HSV-1 or HSV-2 in an individual previously seropositive to the other viral type. Manifestations tend to be milder than those of primary infection.
Type-specific antibody to the prior infection is
present initially. Antibody to new infection may
take several weeks to a few months to appear.
- First episode, recurrence
Twenty-five percent of patients with first clinical
episode of HSV-2 have had a prior unrecognized
primary or non-primary first infection. Type-specific
antibody is present when the patient presents and
the severity of the episode is comparable to a
- Recurrent symptomatic infection is defined as infection in which the antibody is present when symptoms appear, although the patient may not be aware of previous episodes. Disease is usually mild and short in duration.
- Asymptomatic infection is defined as infection in which serum antibody is present, but there is no known history of clinical outbreaks. However, up to two thirds of patients with identified asymptomatic HSV-2 infection
may actually have unrecognized symptomatic infection. Patients should be informed about clinical signs and symptoms of genital herpes, as this may help them recognize symptomatic infection.
The following table compares the infection types.
(Click on image for larger view)
Page last modified: June 3, 2009
Page last reviewed: June 3, 2009
Division of STD Prevention,
National Center for HIV/AIDS,
Viral Hepatitis, STD, and TB Prevention