The experimental vaccine known as Simplirix which was designed to block the transmissions of herpes from men to women has failed a major clinical trial that would prevent manufacturing approval. As a result, pharmaceutical giant GlaxoSmithKline has announced they will not pursue any further attempts to develop the vaccine.
The vaccine, Simplirix, was designed to protect against the two major herpes simplex viruses, HSV-1 and HSV-2.
The National Institute of Allergy and Infectious Diseases, which co-sponsored the trial with GlaxoSmithKline, announced Thursday that the vaccine provided no more than 20% protection against infection, a level that was not statistically different from zero. Researchers do not yet know why the vaccine failed.
They are 2 different serotypes that infect humans. HSV type 1 most commonly infects the mouth and lips, causing sores known as fever blisters (95%). It is also an important cause of genital infection.
HSV type 2 is the usual cause of genital herpes, but can also infect the mouth.
Estimates of up to 90% of adults possess antibody against HSV-1. Initial infection with HSV-1 usually occurs before 5 years of age.As far as HSV-2; in the U.S., there are 45-50 million people over 12 years of age infected. HSV-2 antibody occurs in 20-30% of American adults. According to the Centers for Disease Control and Prevention (CDC), HSV-2 is more common in women (about 1 out of 4 women) than men (about one out of eight).
With HSV-1 contact with the virus in saliva of carriers is probably the most important mode of spread.
Most people get HSV-2 by sexual contact with someone who is shedding the virus either during an outbreak or during a period with no symptoms. People who do not know they have herpes play an important role in transmission of the virus.
Both types 1 and 2 may be transmitted to various sites by oral-genital, oral-anal or anal-genital contact. It can also be transmitted by close skin to skin contact.
There is no cure or vaccine available for herpes. There are antivirals that can prevent or shorten outbreaks.