From the Guidelines
Approximately 87% of people infected with Herpes Simplex Virus (HSV) remain asymptomatic without any outbreaks, as evidenced by the fact that only 13% of HSV-2–seropositive persons had been diagnosed with genital herpes 1. This phenomenon, known as asymptomatic infection, is quite common with HSV. The virus establishes latency in nerve cells after initial infection, where it can remain dormant indefinitely. Many people acquire HSV-1 (oral herpes) during childhood through casual contact, while HSV-2 (genital herpes) is typically transmitted through sexual contact.
- Key points to consider:
- Even without symptoms, these individuals can still shed the virus and potentially transmit it to others, though transmission risk is lower than during active outbreaks.
- The immune system plays a crucial role in controlling viral replication, which explains why some people never develop symptoms while others experience recurrent outbreaks.
- Factors like stress, illness, hormonal changes, and immune suppression can trigger reactivation in those who do have symptoms.
- Blood tests can detect HSV antibodies in asymptomatic individuals, confirming infection despite the absence of clinical manifestations. According to the 2021 Centers for Disease Control and Prevention Sexually Transmitted Infections Treatment Guidelines, as reviewed in the article by Christine Johnston 1, genital herpes is a chronic sexually transmitted infection (STI) characterized by recurrent, self-limited genital ulcers, caused by herpes simplex virus type 1 (HSV-1) or type 2 (HSV-2).
- Important statistics:
- 47.8% and 12.1% of the United States (US) population aged 14–49 years are seropositive for HSV-1 and HSV-2, respectively, in 2015–2016.
- HSV-1 seroprevalence reflects oral and genital infection, but HSV-1 is an increasing cause of first-episode genital herpes, particularly in well-resourced settings. The fact that most people with genital herpes are unaware of their infection highlights the importance of accurate diagnosis and management, as well as patient education on the natural history of the infection 1.
From the Research
Prevalence of Herpes Simplex Virus (HSV)
- The statistics indicate that 50-90% of adults worldwide are seropositive for HSV, mainly HSV-1 and HSV-2 2.
- A study found that the overall age-adjusted HSV-2 seroprevalence was 17.0% in 1999-2004 and 21.0% in 1988-1994, a relative decrease of 19.0% between the two surveys 3.
- Another study reported that HSV-2 seroprevalence was 16.2% overall, with 81.1% of those infected not having received a diagnosis 4.
Asymptomatic HSV Infection
- The exact percentage of people with HSV in the blood who remain asymptomatic without any outbreaks is not directly stated in the provided studies.
- However, it is mentioned that among those infected with HSV-2,81.1% had not received a diagnosis, suggesting that many people with HSV-2 infection may not exhibit symptoms 4.
- Additionally, a study found that the proportion of newly diagnosed genital herpes infections resulting from HSV-1 increased from 31% in 1993 to 78% in 2001, but it does not provide information on the percentage of asymptomatic cases 5.
HSV-1 and HSV-2 Seroprevalence
- The seroprevalence of HSV-1 decreased from 62.0% in 1988-1994 to 57.7% in 1999-2004, a relative decrease of 6.9% between the two surveys 3.
- A study reported that HSV-1 accounted for 78% of all genital isolates in a population of college students by 2001, compared with 31% of isolates in 1993 5.
- The emergence of acyclovir-resistant HSV-1 has been recognized as an emerging clinical problem among patients undergoing hematopoietic stem cell transplantation (HSCT) 6.