Jump to content
World's Largest Herpes Support Group

HSV529 Genital Herpes Vaccine Update

Recommended Posts


HSV529 Genital Herpes Vaccine

Fact checked by Robert Carlson, MD


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.

This Sanofi Pasteur vaccine candidate is derived from HSV2 strain 186, was produced in Vero cells expressing HSV2 UL5 and UL29 and is manufactured by Sanofi Pasteur. 

In October 2014, Sanofi Pasteur and Immune Design announced a collaboration: Sanofi Pasteur will contribute HSV-529, a clinical-stage replication-defective HSV vaccine product candidate, and Immune Design will contribute G103, its preclinical trivalent vaccine product candidate


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

Worldwide, about 400 million people are infected with herpes simplex virus type 2 (HSV2), the predominant cause of genital herpes. HSV2 can also cause encephalitis or disseminated infection in neonates and severe disease in immunocompromised patients.

Genital herpes is an STD caused by two types of viruses. The viruses are called herpes simplex virus type 1 (HSV-1) and HSV-2.

Genital herpes infection is common in the United States. The CDC estimates that, annually, 776,000 people in the United States get new genital herpes infections. Nationwide, 11.9 % of persons aged 14 to 49 years have HSV-2 infection. However, the prevalence of genital herpes infection is higher than that because an increasing number of genital herpes infections are caused by HSV-1.

Of the more than 100 known herpesviruses, 8 routinely infect only humans: herpes simplex virus types 1 and 2, varicella-zoster virus, cytomegalovirus, Epstein-Barr virus, human herpesvirus 6, human herpesvirus 7, and Kaposi's sarcoma virus or human herpesvirus 8. A simian virus, called B virus, occasionally infects humans. All herpesviruses can establish latent infection within specific tissues, which are characteristic of each virus.

Vaccine-elicited protection against HSV is challenging to achieve due to the ability of herpesviruses to evade many aspects of the mammalian immune response. 

Subunit vaccines, which consist of individual or small groups of viral antigens, remove the risk of complications resulting from the production of vaccine-associated infectious viral particles but are limited in the degree and scope of immunity that can be produced in vaccinated individuals. 

The challenge of achieving vaccines that are both safe and effective has led to two opposing approaches in HSV vaccine development: increasing the efficacy of subunit vaccines and increasing the safety of live-attenuated vaccines.


The vaccine candidate was delivered by intramuscular injections. Each dose in the last clinical trial was a 0.5-mL solution containing 1 × 107 plaque-forming units of HSV529.


August 2019: This first-in-human study of the replication-defective HSV vaccine HSV529 showed that it was safe and well-tolerated, with evidence of immunogenicity in HSV-naive and previously infected subjects, 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

Prior studies to prevent HSV infection have focused on subunit vaccines with a goal to induce neutralizing antibodies. HSV2 dl5-29 is a replication-defective HSV2 vaccine that can infect cells and should result in a broader immune response. Based on animal studies demonstrating that HSV2 dl5-29 was superior to an HSV2 glycoprotein D (gD2) subunit vaccine.

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.

Share this post

Link to post
Share on other sites

The Phase II trial has already started.  It's discussed in this thread:


Share this post

Link to post
Share on other sites

do you think this HSV529 is more hopeful or the Monoclonal Antibody Therapy?

Share this post

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Donate

    If Honeycomb has helped you, please help us by making a donation so we can provide you with even better features and services.

  • The Hive is Thriving!

    • Total Topics
    • Total Posts
  • 0_unsure-if-it-is-herpes.png

    Nervous about dating with herpes? Skip "the talk" and browse profiles here.

  • Posts

    • Cas9
      Regarding Excision BioTherapeutics, apparently in animals. Here's their pipeline. https://excisionbio.com/pipeline/ Note that they are expecting to go to human trials second quarter of this year. We'll see if it happens since these pipeline dates often change. By the way, there are also other companies making progress for an HIV cure.
    • veagle
      no way.. there's cure for HIV? 
    • DrumLoop8
      I'm glad I did the WB and can move forward. Thank you @WilsoInAus for being helpful with my many questions too. And also to @Tone123 who without his help, it would have been very difficult to Get the ball rolling! Thank you so much man. I owe you big time.
    • WilsoInAus
      Hey @DrumLoop8 terrific that you have a firm answer and are able to move forward with confidence. Thanks for reporting back on the outcomes, really great insights for others that may have similar concerns and unsure of how to proceed!
    • WilsoInAus
      There is no evidence that is the case, it was a belief but has never been shown in vivo. And even in vitro, a lab, the results are inconclusive as to whether arginine has any impact, beneficial or adverse.
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.