Herpes vaccine fails clinical trial

Simplirix , an experimental vaccine to stop genital herpes recently failed its clinical trial, and the vaccine’s manufacturer, GlaxoSmithKline, has announced it will abandon any further plans to develop the vaccine.

The vaccine was designed to protect against the two major herpes simplex viruses - HSV-1 and HSV-2, the Los Angeles Times reports. HSV-1 is the leading cause of cold sores, while HSV-2 is the primary cause of genital herpes.

The viruses can be transmitted through sexual or skin-to-skin contact, even when no lesions are apparent. Once a person is infected, the virus migrates to nerve cells, where it can remain permanently.

Researchers told the Los Angeles Times that in an initial trial in men and women whose partners were infected with the virus, the vaccine reduced genital herpes by 70 percent in women, but provided little benefit to men.

In the latest trial, called Herpevac, 8,323 women between the ages of 18 and 30 received either Simplirix or Havrix, a vaccine that protects against hepatitis A, the Los Angeles Times reports. Results showed that the vaccine provided no more than 20 percent protection against infection.

Researchers told the Los Angeles Times that they do not yet know why the vaccine failed.

Officials said participants who received Simplirix will be offered the opportunity to receive Havrix.