An effective vaccine against herpes viral infections caused by either HSV-1or HSV-2 remains elusive. Genital herpes (primarily caused by HSV-2) is notorious for promoting HIV infection. It contributes more to the HIV epidemic than any other biological factor. Mathematical models suggest that vaccinating against HSV-2 could have a major effect on HIV transmission. An ideal vaccine would not only protect against both HSV-1 and HSV-2 but would also protect people already infected with HSV-1, which is more commonly associated with oral disease and is highly prevalent worldwide.

In a study published online on May 7 in npj Vaccines, Betsy Herold, M.D., and colleagues showed that their experimental HSV-2 vaccine, called ΔgD-2, protects against HSV-2 infection in mice already infected with HSV-1. When the researchers vaccinated mice that were infected with HSV-1 using a different vaccine candidate called rgD-2, it provided no significant protection against HSV-2 superinfection—consistent with earlier failed clinical trials with that vaccine. By contrast, the ΔgD-2 vaccine completely protected the HSV-1-infected mice from HSV-2 superinfection.

Dr. Herold is professor of pediatrics, of microbiology & immunology, and of obstetrics & gynecology and women’s health at Einstein. Dr. Herold also holds the Harold and Muriel Block Chair in Pediatrics at Einstein and is chief of the division of pediatric infectious diseases and vice chair for research at both Children’s Hospital at Montefiore and Einstein.