There are two types of Herpes Simplex Virus, termed HSV-1 and HSV-2. These two viruses are widespread, have distinctly different DNA, and both can cause oral and genital lesions.

HSV-1 causes about 80% of all oral lesions and only about 20% of genital lesions, while HSV-2 causes the reverse (80% genital and 20% oral). Studies also suggest that in adolescents, up to 40% of genital herpes is caused by HSV-1 because of transmission by oral sex.

Oral herpes (HSV-1)

Oral herpes causes painful sores on the lips, gums, tongue, roof of the mouth, inside the cheeks, and sometimes on the face and neck. It can also cause symptoms such as fever and muscle aches.

Oral herpes is common. About 65% of the population has detectable antibodies to HSV-1 by the age of 40. People commonly refer to the infection as herpes labialis or "cold sores."

Genital herpes (HSV-2)

Genital herpes is a sexually transmitted disease. It causes recurrent painful genital sores in many adults, can be severe in people with suppressed immune systems and in most people who know they are infected frequently causes psychological distress and it becomes a "social" disease. Signs of the infection, when visible, are one or more blisters on or around the genitals or rectum. The blisters then break and turn in tender ulcers (sores) that take up to four weeks to heal.

Genital herpes can cause fatal infections in babies and, hence if acquired during pregnancy, imposes a cesarean delivery. Genital herpes has been also implicated in the spread of HIV, the virus that causes AIDS, since it has been suggested that Herpes can make people more susceptible to HIV infection, and it can make HIV-infected individuals more infectious.

Results of epidemiological studies show that genital herpes infection is common and affects one out of six people (16%) of 14 to 49 years of age. Genital HSV-2 infection is more common in women (approximately one out of five women of 14 to 49 years of age) than in men (about one out of nine men of 14 to 49 years of age).

VAXXIT has IPR rights to a promising live recombinant HSV vaccine that in challenge studies in mice, injected with lethal doses of wild-type HSV-1, provided 100% protection; conversely all mice in the control group, vaccinated with a similar recombinant HSV vector and injected with lethal doses of wild-type HSV-1, died.