A novel herpes vaccine, developed by scientists from the Perelman School of Medicine at the University of Pennsylvania, has achieved a nearly 100-percent success rate in animal testing. The novel vaccine takes a three-pronged approach to preventing viral infection with researchers hoping to soon move into human safety and efficacy trials.
Scientists have been trying to develop an effective herpes vaccine for almost a century, but most traditional vaccine strategies, such as deploying inactivated and replication-defective forms of the virus, have consistently failed at different stages. Recent advances in cellular and molecular immunology over the past decade have resulted in a number of new potential herpes vaccines moving through development.
This latest vaccine is targeted at producing immunity against herpes simplex virus type 2 (HSV-2), one of the world’s most common sexually transmitted diseases with anywhere from 10 to 20 percent of people infected. Most subjects infected with HSV-2 are asymptomatic and can remain undiagnosed for much of their life.
Many current herpes vaccines in development work by blocking the virus’ entry into human cells. This newly developed vaccine stimulates a trio of different antibodies, only one of which blocks the virus from entering cells. The other two molecules block the efficacy of immune-evading strategies deployed by the herpes virus.
In animal tests this trivalent vaccine demonstrated extraordinarily positive results. After one month, 63 of 64 mice tested displayed complete sterilizing immunity, meaning they had no trace of the disease after exposure. Eight of 10 guinea pigs tested also displayed complete immunity, while the remaining two animals only showed minor signs of infection.
“We’re extremely encouraged by the substantial immunizing effect our vaccine had in these animal models,” says Harvey Friedman, principal investigator on the study. “Based on these results, it is our hope that this vaccine could be translated into human studies to test both the safety and efficacy of our approach.”
Further work is necessary before the vaccine moves into human trials, but these early results offer the most promising animal results of any herpes vaccine produced to date.
The new research was published in the journal Science Immunology.
Source: Penn Medicine