What Icosavax does

Icosavax was a Seattle-based, clinical-stage biopharmaceutical company founded in 2017 that developed vaccines against respiratory infectious diseases using a proprietary virus-like particle (VLP) platform. Its lead program, IVX-A12, was a first-in-class bivalent vaccine candidate designed to provide single-immunization protection against respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) — two pathogens for which no combination vaccine previously existed. The VLP technology uses self-assembling protein nanoparticles to display target antigens, enabling robust immune responses without live virus, and was supported by computational protein design capability associated with co-founder David Baker.

The company targeted high-need patient populations including infants and young children, immunocompromised individuals, and high-risk adults aged 18-59, addressing prevention gaps in RSV and hMPV where approved vaccines remained limited. Icosavax was venture-backed, raising approximately $235 million across rounds from 2019 to 2023 from a syndicate including RA Capital, Qiming Venture Partners, Sanofi Ventures, Viking Global, Cormorant Asset Management, and the Bill & Melinda Gates Foundation. The company reported positive Phase I data for its RSV program and advanced IVX-A12 into Phase II, presenting interim data at IDWeek 2024.

In February 2024, AstraZeneca acquired Icosavax for approximately $1.1 billion, integrating the VLP platform and IVX-A12 into AZ's respiratory vaccine pipeline. Icosavax did not generate commercial product revenue; its pre-acquisition economics were driven by milestone-based R&D progress and an eventual strategic exit rather than product sales or licensing royalties. Post-acquisition, Icosavax operates as a wholly-owned subsidiary of AstraZeneca with clinical development continuing within AZ's broader vaccines organization.

Name

Icosavax

Legal name

Icosavax, Inc.

Website

https://icosavax.com

Company type

Private

Founded year

2017

Operating status

Acquired

Headcount range

51–100 employees

Short description

Icosavax was a Seattle-based clinical-stage biotech developing VLP-based vaccines, led by IVX-A12, a first-in-class bivalent vaccine targeting RSV and hMPV. Founded in 2017, it was acquired by AstraZeneca in February 2024 for approximately $1.1 billion.

Ownership category

akta.pro rank

Product category

Infectious Disease Vaccine Development

NAICS

Biological Product (except Diagnostic) Manufacturing (325414), Pharmaceutical Preparation Manufacturing (325412)

SIC

Biological Products, (No Disgnostic Substances) (2836), Pharmaceutical Preparations (2834)

akta.pro primary industry

Vaccine Technology Platforms (mRNA, viral vector, protein subunit, inactivated/live-attenuated, VLP, DNA) (HLAAAEAD)

akta.pro secondary industry

Seasonal & Endemic Vaccines (e.g., Influenza) (HLAIAEAD)

Keywords

• Virus-like particle vaccines
• Respiratory syncytial virus vaccines
• Combination vaccine candidates
• Infectious disease vaccines
• VLP vaccine platform

Headquarters

HQ city

Seattle

HQ country

United States

HQ region

North America

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Technology or R&D, Personnel, Operations

Revenue model

1. Vaccine Development and Commercialization: Pre-acquisition, Icosavax was a clinical-stage biotech developing vaccines. Post-acquisition (February 2024), the company became part of AstraZeneca's portfolio with the RSV/hMPV combination vaccine candidate IVX-A12 advancing through clinical development.

Go-to-market motion1 record

Marketing channels1 record

Core offering

Icosavax develops vaccines for infectious diseases using a proprietary virus-like particle (VLP) technology platform. Its primary product candidate, IVX-A12, is a first-in-class bivalent vaccine targeting both respiratory syncytial virus (RSV) and human metapneumovirus (hMPV). The company was acquired by AstraZeneca in February 2024 for approximately $1.1 billion, with the vaccine candidate continuing clinical development under AstraZeneca.

Product overview

Icosavax is a biopharmaceutical company focused on developing vaccines using virus-like particle (VLP) technology. The company's primary product candidate is IVX-A12, a first-in-class bivalent RSV/hMPV combination vaccine. Following its acquisition by AstraZeneca in February 2024 for approximately $1.1 billion, the IVX-A12 candidate is being advanced through clinical development as part of AstraZeneca's infectious disease vaccines portfolio. Prior to acquisition, Icosavax had raised $67.8 million and reported positive Phase I data for its RSV vaccine program.

Differentiator

Problem solved

Functional benefit

Products and services

• IVX-A12

Quantifiable outcome

• 90% reduction in RSV-associated hospitalizations among infants (Beyfortus/nirsevimab in first season)

Segments3 records

Ideal customer profiles1 record

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature2 records

Scale indicators3 records

Recent moves6 records

Expansion highlights5 records

Direct peers

• Novavax: Novavax uses a recombinant protein nanoparticle (Matrix-M adjuvant) platform that is functionally analogous to Icosavax's VLP technology for vaccines; it is the closest technology and product-category peer.
• Vaxcyte: Vaxcyte develops protein VLP/conjugate vaccine candidates targeting respiratory and bacterial pathogens using a similar structure-based vaccine design approach, making it a direct technology peer.
• Moderna: Moderna is developing mRNA-based RSV vaccines (mResvia is approved) and competing in the same respiratory vaccine market, using a different but adjacent vaccine technology platform.

Emerging players

• Bavarian Nordic: Bavarian Nordic is a commercial-stage vaccines company focused on infectious diseases with a respiratory/infectious disease pipeline that overlaps Icosavax's therapeutic focus.
• CureVac: CureVac develops mRNA-based vaccines for infectious diseases including respiratory pathogens, making it a comparable technology-and-target peer in the vaccines space.
• Arcturus Therapeutics: Arcturus develops mRNA vaccines including for respiratory pathogens (e.g., COVID), positioning it as a technology peer pursuing infectious disease vaccines via a different but related modality.
• Meissa Vaccines: Meissa is developing a live-attenuated intranasal RSV vaccine, making it an emerging direct competitor in the RSV vaccine space targeting the same indication as IVX-A12.

Broad incumbents

• Sanofi: Sanofi co-developed Beyfortus (nirsevimab), an RSV antibody competing in infant RSV prevention, and was itself an Icosavax investor; Sanofi is a broad incumbent with major respiratory vaccine and biologics portfolio.
• Pfizer: Pfizer's ABRYSVO is an approved RSV vaccine directly competing with IVX-A12's target indication, and Pfizer is a broad incumbent in the vaccines space with global commercial reach.
• GSK: GSK's Arexvy is an approved RSV vaccine competing for the same older-adult population; GSK is a broad incumbent in vaccines with established physician relationships and global distribution.

Market position

Strengths4 records

Weaknesses4 records

Competitive moat3 records

Key risks5 records

Key highlights7 records

Customer concentration

• Xx.com/Icosavax
• Facebookfacebook.com/Icosavax
• LinkedInlinkedin.com/company/icosavax

Revenue estimate

Valuation estimate

Number of profiles

Profiles2 records

Funding overview

Funding rounds7 records

Investors19 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 Icosavax