American Sexual
Health Association

The Search for a Herpes Vaccine

The need for a herpes vaccine is clear: about half a billion people worldwide between the ages of 15-49 have genital herpes infection caused by either HSV-1 or HSV-2, according to the World Health Organization (WHO). In the United States alone, an estimated 1 in 6 adults have genital herpes, with around 300,000 new infections diagnosed each year.

While HSV is typically a mild infection, there are potential health risks associated with it, including neonatal herpes, a serious and sometimes fatal condition that occurs when HSV is passed to an infant during delivery. Another concern is the increased risk of HIV infection. The risk of getting HIV (if exposed) is increased 2-3 fold for someone with genital HSV-2 infection.

Researchers have been working on developing herpes vaccines for decades. There have been a number of clinical trials aimed at testing both therapeutic (intended to reduce recurrences and viral shedding in people who are already infected with HSV) and preventive (designed to prevent infection) vaccine candidates.

How do clinical trials work?

Before a treatment regimen or vaccine can become standard, it must go through a clinical trial. Clinical trials test if a potential treatment or vaccine is safe and effective in humans. Clinical trials go through a series of phases, starting with a smaller group of patients and expanding to a much larger group.

Herpes Vaccine Clinical Trials

There are currently both preventive and therapeutic vaccines under development. While the primary focus is on HSV-2, the primary cause of genital infection, HSV-2 vaccines may also have benefits in preventing or treating HSV-1 infection. In addition to work being done in the preclinical stage, there are several vaccines in clinical trials.

More information on recent and ongoing clinical trials can be found at:

For more on herpes vaccine development, see this article.

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