What Rational Vaccines does

Rational Vaccines, Inc. is a privately-held, investigational-stage biotechnology company founded in 2015 and headquartered in Woburn, Massachusetts, developing rationally engineered live-attenuated viral immunotherapeutic and prophylactic vaccine candidates targeting herpes simplex virus 1 (HSV-1) and herpes simplex virus 2 (HSV-2). The company's core technology is based on specifically designed mutations in the ICP0 (Infected Cell Protein 0) gene, which controls the balance of HSV latency and replication. The attenuation approach weakens the virus while retaining its ability to replicate at the site of injection and elicit broad humoral and cellular immune responses. The platform originated from research at Louisiana State University under Dr. Konstantin Kousoulas and is patent-protected (US patent on VC2 live-attenuated vaccine and uses as a vector for other diseases).

The product portfolio includes the lead candidate RVx-201, a therapeutic HSV-2 vaccine with UK ILAP designation that has completed a Phase 1 first-in-human study with five-year safety follow-up; RVx-2001 (prophylactic HSV-2); RVx-1001 (prophylactic HSV-1); and RVX10 for ocular herpes. The company states it has seven vaccine candidates in its pipeline. Beyond vaccines, Rational Vaccines developed the ABVIC serological assay platform, which tests for antibodies to most viral proteins and employs cross-reacting antibody subtraction to reduce false positives; the platform was originally built for HSV diagnostics and was adapted in 2020 into the ABVIC SARS-CoV-2 IgG Test. The HSV immunotherapeutic is also being adapted into a viral vector format for broader application including potential SARS-CoV-2 vaccine use.

The company is pre-revenue and currently sustained by non-dilutive NIH grant funding ($2.8 million in October 2023) alongside prior equity financings totaling approximately $28.6 million across disclosed rounds between 2015 and 2020, with investors including Presight Capital, Founders Fund, and Thiel Capital. Its go-to-market is centered on clinical trial site engagement, regulatory advancement, and scientific conference presence (BIO International Convention, Biotech Showcase, Jefferies London Healthcare Conference). Target patient populations include symptomatic HSV-1/HSV-2 patients, neonates at risk of neonatal herpes, immunocompromised individuals, and patients with ocular herpes. Scientific leadership is anchored by an advisory board including Dr. Stanley Plotkin, Dr. David Bernstein, Dr. Todd Margolis, and Dr. Kousoulas.

Name

Rational Vaccines

Legal name

Rational Vaccines, Inc.

Website

https://rationalvaccines.com

Company type

Private

Founded year

2015

Operating status

Operating

Headcount range

1–10 employees

Short description

Rational Vaccines is a privately-held, investigational-stage biotech developing rationally engineered live-attenuated HSV-1 and HSV-2 vaccine candidates and serological diagnostics based on proprietary ICP0 gene mutations, targeting patients with herpes infections and ocular disease.

Ownership category

akta.pro rank

NAICS

Biological Product (except Diagnostic) Manufacturing (325414), In-Vitro Diagnostic Substance Manufacturing (325413), Scientific Research and Development Services (5417)

SIC

Pharmaceutical Preparations (2834), Biological Products, (No Disgnostic Substances) (2836), In Vitro & In Vivo Diagnostic Substances (2835)

akta.pro primary industry

Therapeutic Vaccines (e.g., Cancer/Chronic Infection) (HLAIAEAG)

akta.pro secondary industries

Vaccine Technology Platforms (mRNA, viral vector, protein subunit, inactivated/live-attenuated, VLP, DNA) (HLAAAEAD), Vaccine Clinical Development & Regulatory Affairs (HLAIAEAM), Pandemic Preparedness & Rapid-Response Vaccines (HLAIAEAF)

Keywords

• Live-attenuated vaccines
• Herpes simplex virus
• Vaccine development
• Serological diagnostics
• Biopharmaceutical research

Headquarters

HQ city

Woburn

HQ country

United States

HQ region

North America

Offices2 records

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Revenue model

1. Vaccine Development & Commercialization: As an investigational-stage biotech company, Rational Vaccines' primary revenue model is not yet established. The company is developing live-attenuated vaccine candidates (RVx-201, RVx-2001, RVx-1001) targeting HSV-1 and HSV-2. Revenue will likely come from product sales upon regulatory approval. The company is also developing diagnostic assays (ABVIC platform). At present, the company is pre-revenue, sustained by NIH funding and potentially other grants/investments.
2. NIH Research Funding: The company received $2.8 million in NIH funding to support research on HSV diagnostics, treatments, and vaccines. This represents non-dilutive grant funding supporting the company's R&D activities.

Go-to-market motion1 record

Distribution channels1 record

Marketing channels6 records

Core offering

Rational Vaccines is an investigational-stage biotech company developing rationally engineered, live-attenuated viral immunotherapeutic and prophylactic vaccine candidates targeting herpes simplex virus 1 (HSV-1) and herpes simplex virus 2 (HSV-2). The company's pipeline includes lead candidate RVx-201 (therapeutic HSV-2), prophylactic candidates RVx-2001 and RVx-1001, ocular HSV candidate RVX10, and the ABVIC serological diagnostic platform adapted for both HSV and SARS-CoV-2 antibody testing.

Product overview

Rational Vaccines is an investigational-stage infectious disease company developing a portfolio of rationally engineered, live attenuated viral immunotherapeutic and prophylactic vaccine candidates focused on herpes simplex virus (HSV-1 and HSV-2). The core technology platform is based on proprietary mutations in the ICP0 viral gene. The lead product is RVx-201, a therapeutic HSV-2 vaccine with UK ILAP designation, alongside prophylactic candidates RVx-2001 (HSV-2) and RVx-1001 (HSV-1). The company also developed RVX10 for ocular herpes. Additionally, the ABVIC™ technology platform spans both HSV serological testing and has been adapted for SARS-CoV-2 antibody detection (ABVIC™ SARS-CoV-2 IgG Test). The HSV Viral Vector Platform enables the technology to be adapted for other disease targets beyond herpes.

Differentiator

Problem solved

Functional benefit

Quantifiable outcome

• RVx-201 predecessor mutant (HSV-2 0ΔNLS) showed 10 to 100 times greater protection against genital herpes than a glycoprotein D subunit vaccine in preclinical studies.
• +5 more outcomes

Segments4 records

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature7 records

Partnerships

Five partnerships are on record, tiered core.

• Louisiana State University (LSU)coreStrategic or Co-development PartnerRational Vaccines maintains a deep partnership with LSU, particularly through Dr. Konstantin Kousoulas who serves as Professor of Virology and Biotechnology at LSU School of Veterinary Medicine and Director of the Division of Biotechnology & Molecular Medicine (BioMMED). The VC2 vaccine technology and patent originated from LSU research. Dr. Kousoulas has constructed and patented herpes simplex viruses at LSU that form the basis of the company's vaccine candidates.
• University of Oklahoma Health Sciences CentercoreStrategic or Co-development PartnerDr. Daniel J.J. Carr, who holds the Stanton L. Young Chair in Ophthalmology at the University of Oklahoma Health Sciences Center, is a member of Rational Vaccines' Scientific Advisory Board and co-authored key publications on the RVX101 vaccine candidate. His research focuses on how HSV and sensory neurons interact to regulate productive and latent viral infection.
• Cincinnati Children's Hospital Medical CentercoreStrategic or Co-development PartnerDr. David I. Bernstein, Professor of Pediatric Infectious Diseases at Cincinnati Children's Hospital Medical Center, serves on Rational Vaccines' Scientific Advisory Board. He has been principal investigator for NIH contracts to study HSV vaccines and antivirals since 1990 and has performed clinical trials of both prophylactic and therapeutic HSV vaccines.
• Washington University in St. LouiscoreStrategic or Co-development PartnerDr. Todd Margolis, Albert and Edson Distinguished Professor and Chair of the Department of Ophthalmology at Washington University, serves on Rational Vaccines' Scientific Advisory Board. His lab research focuses on HSV-neuron interactions and he is protocol chair for AIDS Malignancy Collaborative studies.
• University of OxfordcoreStrategic or Co-development PartnerProf. Georg Holländer, Chair of the Department of Pediatrics at the University of Oxford, serves on Rational Vaccines' Scientific Advisory Board. His research focuses on the development and function of the immune system.

Scale indicators7 records

Recent moves6 records

Expansion highlights4 records

Broad incumbents

• Moderna: Major mRNA vaccine company with an active HSV-2 vaccine program (mRNA-1608) now in clinical development. Comparable as a direct competitor in the HSV vaccine space but with vastly greater capital and platform breadth.
• BioNTech: mRNA-based immunology company with a stated interest in infectious disease vaccines including HSV. Comparable as a competing modality (mRNA vs. live-attenuated) targeting the same HSV indication.
• Sanofi Pasteur: Global vaccine leader with a long history of HSV vaccine R&D efforts. Comparable as a broad incumbent whose eventual commercial launch would define the standard of care Rational Vaccines' products must compete against.
• GSK: Global vaccine incumbent with historical HSV vaccine programs (e.g., Simplirix/Herpevac) and broad infectious-disease capabilities. Comparable as a large established competitor with deeper commercialization reach.
• Novavax: Clinical-stage vaccine company using a recombinant nanoparticle platform. Comparable as a platform-based vaccine company whose experience scaling a novel vaccine modality parallels the manufacturing and regulatory challenges facing live-attenuated HSV vaccines.

Direct peers

• Genocea Biosciences: Direct historical peer developing a therapeutic HSV-2 vaccine (GEN-003). Highly comparable target product, patient population, and clinical-stage positioning; provides a useful precedent for the development and commercial challenges facing Rational Vaccines.

Emerging players

• Tonix Pharmaceuticals: Clinical-stage biotech with TNX-1900, a prophylactic intranasal HSV-2 vaccine candidate in development. Comparable stage, indication, and therapeutic-area focus, providing a useful comp on clinical timelines and capital needs.
• Squarex Pharmaceutical: Early-stage biotech developing a topical live-attenuated HSV vaccine approach (SQX770). Comparable modality (live-attenuated) and indication, with a different route of administration but overlapping scientific and regulatory challenges.
• AiCuris Anti-infective Cures: Specialty anti-infective company with approved HSV antivirals (pritelivir) and a pipeline targeting recurrent HSV. Comparable target indication and therapeutic area, with partial overlap on HSV patient management rather than vaccines specifically.
• Profectus BioSciences: Vaccine developer historically focused on HSV and other infectious disease targets using VesiculoVax platform. Comparable as a peer-stage infectious-disease vaccine company with overlapping HSV-relevant R&D.

Market position

Strengths5 records

Weaknesses4 records

Competitive moat4 records

Key risks6 records

Key highlights6 records

Customer concentration

Revenue estimate

Valuation estimate

Number of profiles

Funding overview

Funding rounds7 records

Investors6 records

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M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Rational Vaccines