Being Specific About Being General: Vaccines Edition

It’s always enormously more difficult to come up with generalized rules and theories than those for specific cases and instances. Generalized artificial intelligence is—thankfully, perhaps—some years off into the distance.

Einstein arrived at the special theory of relativity comparatively easily, and a decade earlier, than his general theory (special theory describes physics in flat spacetime for objects moving at constant speeds, ignoring gravity. General relativity generalizes this to include acceleration and gravitation, which it describes as the curvature of spacetime caused by mass and energy).

In this same way, current licensed flu vaccines are "strain-specific" and must be updated annually to match circulating variants. But the dream is to create a universal flu vaccine. And a certain amount of confidence is now building around that goal.

In this conversation it makes sense to mention five teams of research scientists. A "true" universal vaccine must protect against all human-adapted strains of influenza A and B regardless of mutation.

Challenges now encompass high development costs, the lack of established "correlates of protection" (clear markers that the vaccine worked), the difficulty of outperforming the safety profile of existing seasonal shots, and a waxing and waning of both political allegiances and policies, alongside a set of economics calculations that investors and governments are reluctant to commit to.

Christopher Locher, PhD, CEO, Versatope Therapeutics, Inc., tells his us about his version of a universal flu vaccine while at the Mass Bio annual meeting “State of the Possible.” Versatope trades in recombinant extracellular transport vesicles (RET-Vs) also known as outer membrane vesicles.

Their website explains, “RET-Vs can be engineered to carry precise payloads and attach surface proteins to direct the ETVs to very specific cell types. They are derived from genetically engineered probiotics as a technology platform for the targeted delivery of vaccines and immuno-therapeutics…These designer vesicles can also be used with a time-release formulation that enables long-acting dosing and reduces the number of administrations.”¹

This approach harnesses macrophages, “natures delivery tool to stimulate the immune system, and is usually used to a bacterial cells advantage in the gut. But with the computational biology tools that we have now, we can program these for a better outcome. So, in some ways the mRNA vaccines were a first generation of a frontrunner technology, these bacterial vesicles may surpass that, with new applications for drug delivery.”²

FluMos-v2 is an experimental universal influenza vaccine candidate developed by researchers at the National Institute of Allergy and Infectious Diseases (NIAID) Vaccine Research Center. It is designed to provide broader, longer-lasting protection against a wide variety of influenza strains compared to traditional seasonal flu shots.

This vaccine uses a self-assembling nanoparticle scaffold to display fragments of the influenza virus. “While the FluMos-v1 vaccine candidate displays HA from four strains of influenza virus, FluMos-v2 displays HA from six: four influenza A viruses and two influenza B viruses. The researchers anticipate that this will further broaden vaccine recipients’ immunity, providing protection against a wider variety of influenza viruses.”³

By presenting these proteins in repeating patterns, it trains the immune system to recognize parts of the virus that are common across many different strains, potentially eliminating the need for an annual update. Another approach called “integrated immunity” from Stanford’s Bali Pulendran, examined the well-known “extra” immunity conferenced by the Bacillus Calmette-Guerin tuberculosis vaccine, “which is given to some 100 million newborns every year. Epidemiological and clinical studies have shown that it can decrease infant mortality from other infections, suggesting that the cross-protection could last months. But the phenomenon was inconsistent and the mechanism mysterious.”

Pulendran asks us to imagine “a nasal spray in the fall months that protects you from all respiratory viruses including COVID-19, influenza, respiratory syncytial virus and the common cold, as well as bacterial pneumonia and early spring allergens, that would transform medical practice.”

This vaccine doesn’t try to mimic any part of a pathogen; instead, it “mimics the signals that immune cells use to communicate with each other during an infection. This novel strategy integrates the two branches of immunity—innate and adaptive—creating a feedback loop that sustains a broad immune response.”⁴

Somewhat notoriously, Moderna has had both success and failure with its mRNA-1083, an investigational messenger RNA (mRNA) providing dual protection against both seasonal influenza and COVID-19 in a single injection. It was given European endorsement in February 2026, as the European Medicines Agency's (EMA) drug advisory panel issued a positive opinion for the vaccine. This action marked the first combined mRNA vaccine for adults 50 years of age and older recommended for approval in Europe.

But Moderna voluntarily withdrew its Biologics License Application (BLA) in May 2025 as FDA requested additional Phase 3 efficacy data, specifically for the influenza component. FDA issued a refuse-to-file (RTF) letter for mRNA-1010, saying the company “had not used an appropriate comparator during clinical testing.”

Moderna called the decision "inconsistent" with prior FDA feedback. However, the US regulator subsequently agreed to review the filing after Moderna said it would split the application based on age, setting a target review date of August 5.”⁶

Last, but not least, Centi-Flu 01is acandidate that recently entered Phase 1 human trials, aiming to provide broad protection across multiple flu strains and subtypes. It is designed to focus both antibody and cellular immune responses on conserved regions of the influenza virus that cannot mutate and are shared across strains and distance subtypes.

"For decades, flu vaccination has been reactive," said Sawsan Youssef, PhD, founder and Chief Science Officer of Centivax. "A universal influenza vaccine allows us to be proactive, moving from annual guesswork to predictable durable response.”

To illustrate how many doors this kind of approach might unlock if successful, beyond influenza the epitope-focusing platform explores “a pan-herpes Alzheimer's preventative, a broad oncology treatment, a malaria vaccine, and a universal antivenom.”

The company is supported by over $26M in non-dilutive financing from groups such as the Bill & Melinda Gates Foundation, the Coalition for Epidemic Preparedness (CEPI), the National Institutes of Health (NIH), the United States Department of Agriculture (USDA), the Military Infectious Diseases Research Program (MIDRP), the U.S. Naval Medical Research Command (NMRC), the Department of Defense (DOD), and others. Centivax investors include Future Ventures, NFX, and Global Health Investment Corporation (GHIC).⁷

References

1. Versatope website, Accessed March 30^th, 2026, https://www.versatope.com
2. Christopher Locher, “State of the Possible Conference, MassBio, March 27^th, 2026
3. https://scitechdaily.com/a-shot-at-universality-nih-kicks-off-clinical-trials-for-the-ultimate-flu-vaccine/
4. Bai, N, One vaccine may provide broad protection against many respiratory infections and allergens, Feb 19, 2026, Stanford Medicine
5. Soucheray, A,Double-reverse: FDA now says it will review Moderna’s mRNA flu vaccine, CIDRAP, University of Minnesota, February 18, 2026
6. Bratulic A, EU panel endorses Moderna's dual flu, COVID-19 vaccine, February 27, 2026First word Pharma,https://firstwordpharma.com/story/7118519
7. Centivax Initiates Phase 1 First-in-Human Clinical Trial of Universal Flu Vaccine, Feb 12, 2026, Company press release.