Vaccine Info

HSV529 Genital Herpes (HSV2) Vaccine


HSV529 is a vaccine candidate that is classified as a replication-defective virus, where the virus possesses all the components of the wild-type HSV virus with the exception of two proteins UL5 and UL29 that are involved in viral DNA replication. This replication-defective HSV2 vaccine can infect cells and should result in a broader immune response.


HSV529 is indicated to treat herpes simplex virus (HSV).


The vaccine candidate was delivered by intramuscular injections.


August 2019: HSV529 vaccine was safe and elicited neutralizing antibody and modest CD4+T-cell responses in HSV-seronegative vaccinees.

  • 89 percent of vaccinees experienced mild to moderate solicited injection site reactions compared with 47 percent of placebo recipients
  • 64 percent of vaccinees experienced systemic reactions compared with 53 percent of placebo recipients
  • 78 percent of HSV1 /HSV2 vaccine recipients had a greater than 4-fold rises in neutralizing antibody titer after 3 doses of vaccine, whereas none of the participants in the other serogroups had such responses
  • HSV2-specific CD4+ T-cell responses were detected in 36% 46%, and 27%, of HSV1 /HSV2 , HSV1 /HSV2 , and HSV1 /HSV2 participants, respectively, 1 month after the 3rd dose of vaccine
  • CD8+ T-cell responses were detected in 14%, 8%, and 18% of participants in each group, respectively

Clinical Trial NCT01915212:  Study of the Safety of a Particular Herpes Vaccine in Adults With or Without Herpes Infection (Completed)

The goals of the study are to determine:

  • the safety of HSV529 vaccine in persons with or without HSV infection
  • the ability of the vaccine to elicit immune responses to HSV-2 
  • including virus-specific antibodies and T cell responses to the virus

Three groups of 20 subjects each will be randomized and will receive 3 doses of HSV529 (15 subjects per group) or saline placebo injection (5 subjects per group).

Each subject will be followed for 6 months after the last dose of vaccine.

The 3 groups will be (a) subjects who were infected with HSV-2 in the past but may or may not have been infected with HSV-1 (HSV-1+/-/HSV-2+), (b) subjects who have been infected only with HSV-1 (HSV-1+/HSV-2-), and (c) subjects who have not been infected with HSV-1 or HSV-2 (HSV-1-/HSV-2-).

Vaccine or placebo will be administered on Day 0 and approximately 1 month and 6 months after enrollment.

September 30th, 2019