Centivax Doses First Participants in Phase 1 Trial of Universal Flu Vaccine
Centivax, Inc., a South San Francisco–based biotechnology company, has dosed the first participants in a Phase 1A clinical trial of Centi-Flu 01, a pan-influenza vaccine designed to protect against seasonal, future, and pandemic strains of the virus without annual reformulation. The announcement, made on February 12, 2026, marks the first-in-human test of a universal flu vaccine candidate built on Centivax's computational epitope-focusing platform — a technology that directs both antibody and T-cell responses toward conserved regions of the influenza virus that are shared across strains and subtypes and that resist mutation.
The Centivax clinical trial is a randomized, double-blind, placebo-controlled, dose-escalation study with an open-label, active-controlled phase. It enrolls healthy adults aged 18–64 and a separate cohort aged 65 and older — a population in which current vaccines perform least well. The study's primary endpoints are safety and immunogenicity, with the latter measured by hemagglutination inhibition (HAI) assays against a panel of more than twenty influenza strains, including currently circulating viruses, historical mismatch strains, WHO seasonal guidance strains, and pandemic strains such as H5N1. The trial includes a head-to-head comparison with licensed seasonal flu vaccines using the same HAI correlate of protection that regulators use to approve those products. Initial data from 180 subjects are expected within 2026.
Centivax developed Centi-Flu 01 internally, without in-licensing from academic institutions, under co-founders Jacob Glanville (CEO) and Sawsan Youssef (CSO). The company has received more than $26 million in non-dilutive funding from the Bill & Melinda Gates Foundation, the Coalition for Epidemic Preparedness Innovations (CEPI), the NIH, the Department of Defense, and other U.S. government agencies. No licensing or co-development deals with pharmaceutical partners have been disclosed; Centivax retains full global rights to the program.
Research Context: Why Target Conserved Influenza Epitopes?
The scientific rationale for a broad-spectrum flu vaccine rests on a well-documented limitation of the current approach: seasonal influenza vaccines target the hemagglutinin (HA) head domain, the most immunodominant but also the most variable part of the virus. Because HA head epitopes undergo continuous antigenic drift, vaccines must be reformulated each year based on predictions made months before the influenza season begins. When those predictions miss — as occurs regularly — vaccine effectiveness drops, in some years to as low as 10–20%.
Centi-Flu 01 instead focuses immune responses on conserved epitopes that the virus cannot alter without losing function. The company's computational platform identifies these invariant regions and engineers immunogens that present them in a way that overcomes the immune system's natural tendency to target the variable HA head. The approach aims to generate antibodies directed at the HA stalk and other conserved surface features, as well as T-cell responses against conserved internal proteins — a dual strategy that distinguishes it from candidates that pursue only one arm of adaptive immunity.
Research catalogued in the AllSci database underscores both the opportunity and the complexity of this strategy. An ongoing observational study tracking repeat influenza vaccination in healthcare workers across multiple seasons — using marketed vaccines including Fluarix Tetra, Vaxigrip Tetra, and Fluad Quad — is examining how prior vaccination history shapes subsequent immune responses (AllSci trial listing). Published findings linked in AllSci show that repeat vaccination can reduce antibody affinity maturation against strain-specific HA domains (AllSci article), while other analyses suggest that birth-cohort imprinting effects on HAI titers are inconsistent (AllSci article). These observations point to a central problem: the immune system's response to conventional HA-head-targeted vaccines is shaped — and sometimes constrained — by prior exposure history. A universal influenza vaccine that redirects responses to conserved epitopes could, in principle, sidestep this constraint entirely.
Standard of Care and Its Limitations
The current influenza vaccine market exceeds $7 billion annually and is served by egg-based inactivated vaccines (Sanofi's Fluzone, GSK's Fluarix), cell-based products (Seqirus's Flucelvax), recombinant HA vaccines (Sanofi's Flublok), adjuvanted formulations for the elderly (Seqirus's Fluad), and AstraZeneca's live-attenuated intranasal FluMist. On the treatment side, Shionogi and Roche's baloxavir marboxil (Xofluza) and generic oseltamivir remain the primary antivirals.
Despite this array of products, effectiveness remains unpredictable. In mismatch seasons, vaccinated individuals may receive little or no protection. Enhanced formulations — high-dose vaccines, MF59-adjuvanted products — improve responses in older adults but do not solve the fundamental strain-match problem. Manufacturing timelines of approximately six months mean that the viruses selected for vaccine production may no longer match the strains circulating when doses reach patients. And current vaccines provide immunity lasting roughly four to six months, necessitating annual revaccination.