Genital Herpes Vaccine Going Into Trials

Herpes virus illustration via shutterstock

Sobering news: According to the CDC, one in every six Americans ages 14 to 49 has genital herpes. In fact, in NYC that number (for all age groups) is one in four. One in four. And that was 2008, so who knows how much that number has gone up since then. The good news is that a Harvard doc is working on a vaccine.

Dr. David Knipe, a Harvard Medical School professor of microbiology and molecular genetics has developed an experimental vaccine for genital herpes that’s now being tested in a clinical trial conducted by the National Institute of Health.

Currently, there is no cure for herpes (HSV 1 and HSV 2). Genital herpes is characterized by periodic outbreaks of painful sores and blisters, and alternating long periods of dormancy with no outward symptoms. HSV 1 is often associated with mouth and lip sores. Herpes can also threaten the lives of infants born to infected mothers, cause blindness in some cases, and can lead to encephalitis.

Previous attempts to develop a herpes vaccine resulted in vaccines that prompted the immune system to develop antibodies against the virus, but couldn’t induce a T cell response to kill the already existing virus cells. Knipe says both aspects are needed for a vaccine to be considered safe and effective.

In the 1990s, Knipe and his team of researchers took the first step toward developing this vaccine. They genetically altered the herpes virus so that it couldn’t replicate itself. This mutant version, when it enters the body, elicits both an immune system and a T cell response, but it cannot multiply. Since Knipe’s initial experiments 20 years ago, vaccines for smallpox and experimental HIV vaccines have employed this “replication-defective” type of virus.

In a Harvard Medical School report, Knipe says that herpes may increase the risk of HIV infection:

“There’s a medical need to prevent herpes disease, but the biggest issue is that genital herpes increases the risk of HIV infection,” Knipe says. “A genital herpes vaccine that prevented HSV-2 infection could reduce the risk of HIV infection.”

The current clinical trial hopes to test the effectiveness of this particular vaccine for herpes and by extension, examine the possibility that a similar method could be used to vaccinate against HIV virus.

The study will enroll 60 adults younger than 40 who will divided into three categories: those who have been previously diagnosed with both HSV 1 and HSV 2; either HSV 1 or HSV 2; and those who have never been infected. Participants will receive doses of either the vaccine or a placebo and blood tests will show that vaccine’s effectiveness in eliciting an immune system and T cell response. The study will continue through October 2016.