Herpes vaccine candidate
BNT163
phase 1 BioNTech SE
Last updated:
BNT163 is a prophylactic (preventive) mRNA vaccine candidate for HSV-2, developed by BioNTech. Development phase: phase 1. Phase 1 first-in-human safety trial, active but no longer recruiting. Only a conference abstract on early safety and immune response; no efficacy data.
Page last updated . ClinicalTrials.gov data as of .
| Developer | BioNTech SE |
|---|---|
| Platform | mRNA |
| HSV target | HSV-2 |
| Approach | prophylactic |
| Phase | phase 1 |
| Status | First-in-human Phase 1 trial ongoing (active, not recruiting). Started December 2022; registry lists estimated primary completion October 2026 (record last updated October 2025). Only an early safety and immune-response conference abstract has been published; no efficacy data. |
| Trials | NCT05432583 |
BioNTech's mRNA prophylactic (preventive) vaccine candidate aimed at preventing genital lesions caused by HSV-2, and potentially HSV-1. Its first-in-human Phase 1 trial began in December 2022 and is ongoing but no longer recruiting, with an estimated primary completion of October 2026 on the registry. As of October 2026 it is an early-stage safety and immune-response study; no efficacy results have been published.
What BNT163 is
BNT163 is BioNTech’s prophylactic herpes vaccine candidate — one designed to prevent infection rather than treat an existing one. Its stated goal is to prevent the genital lesions caused by HSV-2, and potentially HSV-1.
It is an mRNA vaccine: it delivers genetic instructions that prompt the body’s cells to make selected viral proteins so the immune system learns to recognize them (for a fuller explanation of the technology, see how mRNA herpes vaccines work). It is a trivalent vaccine, encoding three HSV-2 glycoproteins (gC2, gD2, and gE2), with the aim of blocking the virus from entering and spreading between cells and of countering some of the ways the virus evades immune responses. BNT163 is the clinical form of the trivalent mRNA approach developed at the University of Pennsylvania and licensed to BioNTech — see Trivalent gC2/gD2/gE2 mRNA (UPenn), the BioNTech-linked preclinical program, for the underlying animal science.
Where BNT163 stands
BNT163 is in a first-in-human Phase 1 trial (NCT05432583) evaluating safety, tolerability, and immune responses (including neutralizing antibodies) in adults aged 18–55. The registry describes three parts: a dose-escalation part (A), an expanded safety and dose-evaluation part (B), and a placebo-controlled part (C) in people with a history of recurrent HSV-2 genital herpes. The registry lists 318 participants enrolled. The trial began in December 2022. Its status on ClinicalTrials.gov is Active, not recruiting. The registry gives an estimated primary completion of October 2026; the record was last updated on 2025-10-20, so that estimate has not been revised in the past year and may not reflect the current timeline. We could not check BioNTech’s own trial page.
A Phase 1 study of this kind is designed to answer whether the vaccine is safe and whether it triggers an immune response — not whether it prevents herpes. No efficacy data have been published.
For context within this tracker only: the other tracked programs from BioNTech, GSK, Sanofi and Moderna have registry records listed as Completed or Terminated, so NCT05432583 is the only one of those whose status is still active. This reflects the registry snapshot dated September 28, 2026 and covers only the programs we track. It is not a survey of the whole field.
Registry snapshot
- Registry status
- Active, not recruiting
- Phase
- phase 1
- Enrollment
- 318 (actual)
- Lead sponsor
- BioNTech SE
- Started
- Dec 8, 2022
- Primary completion
- Oct 2026
Registry record last updated Oct 22, 2026.
Background
- How mRNA herpes vaccines work
Several of the most-watched herpes vaccine candidates use mRNA — the same technology behind the COVID-19 vaccines. This explainer covers how an mRNA vaccine delivers instructions for a cell to make selected viral proteins, why several HSV programs chose the approach, and why a platform that works for one disease is not proof it will work for another.
- HSV-1 vs HSV-2: what's the difference?
Herpes simplex virus comes in two types. HSV-1 has traditionally caused oral herpes and HSV-2 genital herpes, but that line has blurred, and either type can infect either site. The distinction still matters for vaccines: a vaccine can protect against one type and not the other, as the Phase 3 Herpevac trial showed. Neither type has an approved vaccine as of 2026.
- Prophylactic vs therapeutic: two very different herpes vaccines
"A herpes vaccine" can mean two different things. A prophylactic (preventive) vaccine is given to people who are not infected, to stop them getting herpes simplex virus (HSV) at all. A therapeutic vaccine is given to people who are already infected, to reduce outbreaks and viral shedding. The two use different trials, endpoints, and populations — so the first question to ask of any candidate is which goal it targets. Neither type is approved.
- What each clinical trial phase does and doesn't prove
A plain-language guide to reading herpes (HSV) vaccine news by trial phase. Each phase answers a different question, and early-phase results say nothing about whether a vaccine prevents disease. A trial existing or finishing is not the same as a vaccine working — the Phase 3 Herpevac trial ran to completion but missed its main goal, and as of 2026 no HSV vaccine has cleared Phase 3 to approval.
- Why gC2, gD2, and gE2? The trivalent vaccine rationale
Several leading HSV-2 vaccine candidates combine three viral surface proteins — gC2, gD2, and gE2 — to do two jobs at once: block the virus from entering cells and disable two of the tricks it uses to evade the immune system. The rationale is well supported by animal data; whether it protects people is still being tested in an early-stage (Phase 1) human trial of the candidate BNT163.
- Why is HSV so hard to vaccinate against?
Herpes simplex virus establishes a lifelong dormant infection in nerve cells and carries genes that actively blunt the immune response, so even natural infection does not stop reinfection or recurrences — a vaccine has to outperform what the body manages on its own. This explainer walks through the four obstacles researchers keep hitting: latency, active immune evasion, unknown correlates of protection, and animal models that do not fully mirror human disease. As of 2026, no HSV vaccine is approved.
Key literature
- A Decade of the Global STI Vaccine Roadmap: Progress, Gaps and Challenges
- Immunogenicity and Efficacy of a Trivalent HSV-2 gC2, gD2, gE2 Nucleoside-Modified mRNA-LNP Vaccine Against HSV-1 Eye Infection and Neuroinvasion in Mice
- Safety and Immunogenicity of BNT163, a Trivalent mRNA HSV Vaccine Candidate for Genital Herpes
Sources
- A Clinical Trial in Healthy Volunteers and Volunteers With Recurrent Genital Herpes to Study the Safety, Tolerability, and Immune Responses After Vaccination With an Investigational Vaccine Designed to Prevent Genital Herpes Lesions (NCT05432583)
- BioNTech Starts Phase 1 Clinical Trial for Prophylactic Herpes Simplex Virus-2 Vaccine Candidate BNT163
- Safety and Immunogenicity of BNT163, a Trivalent mRNA HSV Vaccine Candidate for Genital Herpes (abstract P-105)