What Protein Sciences does

Protein Sciences Corporation is a biotechnology company founded in 1983 and headquartered in Meriden, Connecticut, that developed recombinant vaccines using proprietary baculovirus/Sf9 insect cell expression technology. Its lead product, Flublok, is an FDA-approved recombinant influenza vaccine indicated for active immunization of individuals 9 years of age and older. Flublok contains 3x the antigen content of standard-dose influenza vaccines and demonstrated 30% better protection against PCR-confirmed circulating influenza strains versus a standard-dose quadrivalent inactivated vaccine in adults 50+ in a randomized controlled trial. The cell-based recombinant production platform avoids egg-adapted mutations and allows faster manufacturing timelines than traditional egg-based methods.

Following its 2017 acquisition by Sanofi, Protein Sciences operates as part of Sanofi Pasteur, the vaccines division of the multinational pharmaceutical group. Flublok is now manufactured and distributed alongside Fluzone High-Dose (4x antigen, for adults 65+) and Fluzone (standard-dose, for persons 6 months and older) under the unified Sanofiflu brand. Revenue is generated through vaccine product sales via institutional healthcare distribution, pharmacy channels, and direct e-commerce ordering through VaccineShoppe.com, with vaccines covered by Medicare and most commercial insurers. The company serves a horizontal customer segment spanning pediatric, adult, and elderly populations with a tiered higher-dose vaccine portfolio.

The company employs 51-100 people and was led by Daniel Adams (President and CEO) and founder Steven Zimmer. Post-acquisition, Protein Sciences Corporation is no longer independently traded, and its operations are fully integrated into Sanofi's commercial and manufacturing infrastructure.

Name

Protein Sciences

Legal name

Protein Sciences Corporation

Website

https://proteinsciences.com

Company type

Private

Founded year

1983

Operating status

Acquired

Headcount range

51–100 employees

Short description

Protein Sciences Corporation developed Flublok, a recombinant influenza vaccine using baculovirus insect cell expression technology. Founded in 1983 in Meriden, Connecticut, and acquired by Sanofi in 2017, it now operates as part of Sanofi Pasteur's Sanofiflu vaccine franchise.

Ownership category

akta.pro rank

Headquarters

HQ city

Meriden

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, Supply Chain, Marketing or Sales, Infrastructure

Revenue model

1. Vaccine product sales: Revenue generated from sale of influenza vaccines (Flublok) through healthcare distribution channels, covered by Medicare and commercial insurance plans.

Pricing tiers

Go-to-market motion1 record

Distribution channels1 record

Marketing channels1 record

Core offering

Protein Sciences develops and manufactures recombinant influenza vaccines using proprietary baculovirus expression vector technology in insect cells. Its principal product is a recombinant trivalent/quadrivalent influenza vaccine produced without the use of eggs, intended for adults seeking flu immunization. Following acquisition by Sanofi in 2017, the company operates as part of Sanofi Pasteur.

Product overview

Protein Sciences, now part of Sanofi, offers a portfolio of influenza vaccines under the Sanofiflu brand. The portfolio includes three vaccine products: Flublok (recombinant influenza vaccine, approved for persons 9 years and older, containing 3x antigen content), Fluzone High-Dose (approved for persons 65 years and older, containing 4x antigen content), and Fluzone (standard-dose, approved for persons 6 months and older). These are trivalent/quadrivalent vaccines for active immunization against influenza A and B virus subtypes. The higher-dose formulations (Flublok and Fluzone High-Dose) are proven in randomized controlled trials to provide superior protection in older adults compared to standard-dose vaccines.

Differentiator

Problem solved

Functional benefit

Brands

• Flublok: Recombinant influenza vaccine developed by Protein Sciences Corporation using baculovirus expression technology. Now manufactured and distributed by Sanofi Pasteur Inc.

Products and services

• Flublok Quadrivalent Flublok is a recombinant quadrivalent influenza vaccine approved for adults 18 years and older. It is manufactured using a baculovirus expression vector system (BEVS) in Sf9 insect cells rather than egg-based production, enabling faster manufacturing and avoiding egg-derived protein. Each dose contains 45 micrograms of hemagglutinin per strain (180 µg total) and is FDA-approved.

Quantifiable outcome

• 30% better protection against influenza due to any PCR-confirmed circulating strains vs standard-dose quadrivalent inactivated influenza vaccine in adults 50 years of age and older

Segments1 record

Ideal customer profiles1 record

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature1 record

Scale indicators1 record

Expansion highlights4 records

Broad incumbents

• Pfizer: Develops influenza vaccines (including ABFCell cellular technology and mRNA programs) and is a major US flu competitor. A broad incumbent whose flu offerings overlap Flublok's target market.
• GSK: Major vaccine incumbent with influenza products (Fluarix, Flulaval) and broad vaccine portfolio. Competes against Flublok in the same seasonal flu market but operates across many other vaccine categories.

Direct peers

• Sanofi Pasteur: Parent entity of Protein Sciences and operator of the Sanofiflu franchise (Flublok, Fluzone, Fluzone High-Dose). It is the most directly comparable competitor-distributor in seasonal influenza vaccines globally.
• CSL Seqirus: Direct competitor in cell-based and recombinant influenza vaccines (Flucelvax). Seqirus also operates a major egg-based portfolio and competes with Flublok in the same US adult and older-adult segments through similar distribution channels.
• Novavax: Uses recombinant protein nanoparticle technology (Matrix-M adjuvant) to produce vaccines. Shares the recombinant protein-subunit paradigm with Flublok and is a directly comparable biologics-platform vaccine peer.

Emerging players

• Bavarian Nordic: Vaccine-focused biotech with viral vector and recombinant capabilities. Comparable as a smaller specialty vaccine company developing biological platform vaccines for infectious diseases.
• VBI Vaccines: Smaller vaccine biotech with VLP and enveloped virus platforms targeting infectious disease. Comparable as a platform-vaccine peer focused on differentiated recombinant/virus-like particle approaches.
• Moderna: Developing mRNA-based seasonal and pandemic influenza vaccines. Represents the next-generation platform risk to recombinant and egg-based flu vaccines such as Flublok.
• Emergent BioSolutions: CDMO and vaccine developer with biologics manufacturing capabilities. Operates in adjacent vaccine/biodefense space and shares scale, regulatory complexity, and biologics manufacturing characteristics with Protein Sciences.

Others

• Dynavax Technologies: Vaccine adjuvant and recombinant hepatitis B vaccine (Heplisav-B) company. Adjacent peer supplying enabling vaccine technology and competing for share in adult immunization channels that also buy Flublok.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat4 records

Key risks5 records

Key highlights6 records

Customer concentration

• Xx.com/proteinsciences
• LinkedInlinkedin.com/company/70809

Revenue estimate

Valuation estimate

Number of profiles

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

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

Frequently asked questions about Protein Sciences