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Where each herpes vaccine candidate actually stands

A neutral, evidence-first tracker of herpes-simplex-virus (HSV) vaccine research. Every status claim is sourced and dated. We do not sell anything, promise timelines, or promote any candidate.

Registry data (ClinicalTrials.gov) as of · Tracker last changed

Candidates tested in people

Prophylactic means designed to prevent infection; therapeutic means designed to treat people who already have HSV. Programs are grouped by whether ClinicalTrials.gov lists a trial as ongoing, then listed A to Z. The order is not a ranking and says nothing about which program will work. A trial existing is not evidence that it will succeed.

No trial listed as ongoing · 6

G103 phase 1 Sanofi Pasteur HSV-2 · therapeutic · protein subunit No ongoing trial Three-protein therapeutic vaccine. A 2025 report covers 24 participants; the related Sanofi trial was terminated for business reasons. Last primary-sourced change: May 2021, Related Sanofi trial terminated (registry) GSK4108771A phase 1 GlaxoSmithKline HSV type unclear · aim unclear · other No ongoing trial Phase 1 dose-escalation trial terminated in 2021 to develop an enhanced version. No results posted. Last primary-sourced change: May 2021, Phase 1 trial terminated (registry) HerpV phase 2 Agenus HSV-2 · therapeutic · protein subunit No ongoing trial Phase 2a trial in 80 adults completed in 2015, with results posted. No record lists an ongoing trial. Last primary-sourced change: Jan 2015, Phase 2a trial completed (registry) HSV529 phase 1 Sanofi Pasteur HSV-2 · prophylactic and therapeutic · replication-defective live No ongoing trial Three phase 1 trials. Raised antibodies in people never infected, not in those already infected. No efficacy trial; none active. Last primary-sourced change: May 2021, Related Sanofi trial terminated (registry) pPJV7630 phase 1 PowderMed HSV-2 · therapeutic · DNA No ongoing trial Two phase 1 trials, completed in 2005 and 2006. No results posted on the registry. Last primary-sourced change: Dec 2006, Second phase 1 trial completed (registry) VCL-HB01 phase 2 Vical HSV-2 · therapeutic · DNA No ongoing trial Phase 1/2 and phase 2 trials (165 and 261 people) completed by 2018. No results posted on the registry. Last primary-sourced change: Dec 2018, Phase 2 trial completed (registry)

Discontinued · 3

GEN-003 discontinued Genocea HSV-2 · therapeutic · protein subunit Therapeutic vaccine that reduced viral shedding and lesion rates in phase 2. Genocea halted the program in 2017 and no one has revived it. Last primary-sourced change: Jun 2018, Last registered trial closed, terminated (registry) Herpevac (gD2 subunit, GSK) discontinued GlaxoSmithKline HSV-2 · prophylactic · protein subunit Phase 3 in about 8,300 women: did not prevent HSV-2 genital disease, but reduced HSV-1 genital disease by about 58%. Not advanced. Last primary-sourced change: Jan 2012, Phase 3 results published mRNA-1608 discontinued Moderna HSV-2 · therapeutic · mRNA Phase 1/2 completed April 2025 with interim safety and immune-response data reported. Trade press reported in November 2025 that Moderna ended the program. Last primary-sourced change: Nov 2025, Trade press reported Moderna ended the program

Cautionary history · 1

Theravax / Profavax (Rational Vaccines) cautionary Rational Vaccines HSV-1 and HSV-2 · prophylactic and therapeutic · live-attenuated Not a legitimate candidate: tested offshore in 2016 without ethics or FDA oversight. Kept as cautionary history.

Compare all 16 candidates in the tracker table →

Not yet tested in people

Preclinical means the work so far is in cell culture or animals, mostly mice. Animal results do not predict how a vaccine will perform in people, and none of these entries implies a date for a trial. All preclinical programs →

Show the 4 programs
gG-2 vaccine (EXCT4) preclinical University of Gothenburg HSV-2 · aim unclear · protein subunit Mouse studies only, reporting protection against lethal HSV-2 challenge. No human data and no registered trial. Last primary-sourced change: 2026, Latest mouse study published Prime/Pull/Keep therapeutic vaccines preclinical UC Irvine (BenMohamed lab) HSV-1 and HSV-2 · therapeutic · other Guinea-pig and rabbit studies only, in already-infected animals. The antigens vary between papers. No human data or registered trial. Last primary-sourced change: Apr 2025, Latest rabbit study (HSV-1) published Trivalent gC2/gD2/gE2 mRNA (UPenn) preclinical University of Pennsylvania HSV-2 · prophylactic · mRNA Mouse, guinea pig and primate studies only. Its clinical form is BioNTech's BNT163. Last primary-sourced change: Jun 2026, Latest mouse study published ΔgD-2 preclinical Albert Einstein College of Medicine HSV-1 and HSV-2 · prophylactic · replication-defective live Mouse studies only, reporting protection against HSV-1 and HSV-2 disease. No human data and no registered trial. Last primary-sourced change: 2023, Latest mouse study published

Research and background

Latest research

Each paper is labeled with its publication status.

See all research →

Common questions about herpes vaccines

Short, neutral answers to the questions people most often ask — each links to a page on this site where the claim is sourced and dated.

Is there a herpes vaccine?
No herpes (HSV) vaccine is approved anywhere as of 2026. Several candidates have entered or completed early-stage human trials, but none has been shown to prevent or treat herpes in the way needed for approval. See the candidate tracker →
Is a herpes vaccine coming in 2026?
There is no approved herpes vaccine and no announced approval date. The programs with trials still under way are in early-phase (Phase 1) testing, and a trial existing is not evidence that it will succeed. We do not predict timelines. See how far each candidate has reached → Why an early-phase trial is not an approval →
Which herpes vaccines are in development?
Programs with a trial currently listed as ongoing include BioNTech's BNT163, a preventive mRNA candidate in Phase 1, and an mRNA vaccine from Changchun BCHT in Phase 1. Earlier programs include therapeutic candidates that completed Phase 2 trials, such as Agenus's HerpV and Vical's VCL-HB01, as well as Moderna's mRNA-1608 (discontinued in November 2025), GSK's Herpevac and Genocea's GEN-003. Full tracker with sources → BNT163 → The BCHT mRNA vaccine →
What is the difference between HSV-1 and HSV-2?
HSV-1 has traditionally caused oral herpes and HSV-2 genital herpes, but either type can infect either site. The distinction matters for vaccines: a candidate can protect against one type and not the other. HSV-1 vs HSV-2 explainer →
What is the difference between a preventive and a therapeutic herpes vaccine?
A prophylactic (preventive) vaccine aims to stop an uninfected person from getting HSV. A therapeutic vaccine is for people already infected, to reduce outbreaks and shedding. They use different trials, endpoints, and populations, and a candidate can target one goal and not the other. Prophylactic vs therapeutic explainer →
Why isn't there a herpes vaccine yet?
HSV establishes lifelong latency in nerve cells and evades parts of the immune response, which makes it a hard vaccine target. Several approaches have reached human trials; none has yet cleared the bar for approval. Why HSV is hard to vaccinate against → What clearing each trial phase would take →
Can gene editing or CRISPR get rid of herpes?
Gene editing, often called CRISPR, is not a vaccine. It aims to damage the virus's own DNA inside the nerve cells where HSV lies dormant, instead of training the immune system. Every published result so far is against HSV-1, not the HSV-2 behind most genital herpes: large reductions of dormant virus in mice and rabbits, one study in three patients with severe eye disease, and one trial now enrolling. None of it has produced an approved treatment. Gene editing and herpes, and why it isn't a vaccine →