Researchers at the University of Pennsylvania recently reported that they are close to developing a herpes simplex virus 2 (HSV-2) vaccine for humans. HSV-2 primarily causes genital herpes and is contracted through forms of sexual contact with a person who has HSV-2. An estimated 14 percent of Americans between the ages of 15 and 49 are infected with HSV-2. According to Forbes, the goal of is to make the vaccine work in a similar manner to the current human papillomavirus (HPV) vaccine on the market.1 2 3
Previous attempts to develop a herpes vaccine have failed. However, according to a new study published in Science Immunology, an new experimental HSV-2 vaccine has prevented genital lesions in mice and guinea pigs. According to a report in New Scientist, the vaccine prevented low-level “hidden” infections. Other experimental vaccines initially thought to be promising enough to test in humans have failed to prevent these hidden infections in animals.4
Harvey Friedman, MD, who is a coauthor of the study and an immunologist at the University of Pennsylvania, is quoted as saying that, “This degree of protection is better than any other vaccine candidates have achieved in mice. We also had excellent protection in guinea pigs, which is another animal model used to evaluate genital herpes vaccine candidates.” He adds, “but we won’t know if this vaccine will work until it is tested in humans.”4
Dr. Friedman states that the new HSV-2 vaccine takes a genetics-based approach to preventing herpes transmission. It combines the messenger RNA (mRNA) coding for three proteins found in the virus.4
No mRNA-based vaccine has yet been approved for use in the United States. According to PHG Foundation at University of Cambridge, while RNA vaccines are non-infectious and RNA does not integrate itself into the host genome, the mRNA strand in an RNA vaccine “may elicit an unintended immune reaction.”4 5
Amesh Adalja, MD, a senior scholar at Johns Hopkins Center for Health Security, says, “the technology has the potential to totally change the face of vaccine development in terms of speed, ease of manufacture and pursuit of novel targets. The promising results seen with this mRNA vaccine in mouse and guinea pig model will hopefully move into human clinical studies and also further the rise of mRNA vaccine technology.”3
Dr. Friedman and his team are in negotiations with a biotechnology company to begin the first stage of human clinical trials in the next year with 50 to 100 people to first test the vaccine’s safety and its ability to produce an immune response.3
If the vaccine is successful in all stages of the human trials, Dr. Friedman said researchers envision it being recommended for children to the onset of sexual activity similar to recommendations for HPV vaccine routinely administered to pre-adolescents.3
1 Dovey D. . Forbes Sept. 24, 2019.
2 Dock E. Herpes Simplex. Healthline Feb. 27, 2019.
3 Thompson D. Experimental Genital Herpes Vaccine Shows Promise in Mice. US & W0rld Report Sept. 26, 2019.
4 Le Page M. Herpes vaccine to be tested in humans after best result yet in animals. NewScientist.com Sept. 20, 2019.
5 PHG Foundation. RNA vaccines: an introduction. University of Cambridge 2019.