Post-acute infection syndromes, including long COVID and ME/CFS

The illness after the infection is real.

Sequela Bio is a biotechnology company working on the persistent, often invisible conditions that can follow a viral infection. We start from one premise: people with the same symptoms may have very different biology, and they deserve treatments matched to it.

From a distance, every patient looks the same. Up close, they don’t.

For many people, a viral infection is only the beginning.

Months or years later, they are still living with symptoms that are hard to measure, hard to explain and, so far, hard to treat.

Hard to see

Standard bloodwork and imaging often come back normal. Patients are told they are fine, or that it is stress.

Hard to name

Symptoms cross neurology, immunology, cardiology and more, so no single specialist sees the whole picture.

Hard to treat

There are no approved drug therapies for long COVID, and trials that treat every patient the same way have largely come up short.

What people describe

These symptoms overlap across many conditions. They are not a basis for self-diagnosis.

  • Trouble concentrating, or “brain fog”
  • Sensitivity to light and sound
  • Fatigue that worsens after exertion
  • Shortness of breath
  • Migraines and headaches
  • Sleep that doesn’t restore
  • Racing heart on standing

Our approach

Same symptoms.
Different biology.

We think post-viral illness is not one disease but several, which happen to look alike from the outside. Progress depends on telling them apart before deciding how to treat them.

  1. Measure

    Build a deep biological profile of each patient, looking past routine tests to the immune, vascular, autonomic and metabolic signals underneath.

  2. Stratify

    Group patients by the mechanism most likely driving their illness, rather than by the list of symptoms they share.

  3. Match

    Develop and rigorously test therapies for the specific subgroups most likely to respond to them.

Why we exist

Maya’s story

A composite patient journey
“Every test said I was fine. I couldn’t get through a single email.”

Maya was thirty-four, a product lead who ran half-marathons and managed a team of twelve. One winter she caught what everyone called a mild virus. She was back at work within a week.

Three weeks later, things began to slip. She would read the same paragraph four times. The office lights felt like pressure behind her eyes, and the sound of a dropped spoon made her flinch. The stairs to her flat left her short of breath. Migraines came two or three times a week. A good day was usually followed by two days in bed.

Her bloodwork was normal. Her heart scan was normal. Her brain MRI was normal. One doctor suggested burnout, another anxiety. She saw a neurologist, a cardiologist, a pulmonologist and an immunologist, and each examined the part of her that fell within their specialty.

What changed her thinking was meeting other people like her. Their symptoms were almost identical, but their responses were not: what helped one person did nothing for the next. It became hard to avoid the conclusion that they did not share one illness. They shared a set of symptoms sitting on top of several different ones.

That idea, that the same symptoms can come from different biology, is the reason Sequela Bio exists.

Maya is a composite based on experiences commonly reported by people living with post-viral illness. She is not a real person, and her story is illustrative.

How we work

Patients as partners

People living with post-viral illness help shape what we study, how we measure it and what counts as meaningful improvement.

Evidence before claims

We will not describe anything as a treatment until rigorous, controlled trials show that it works.

Trials designed for differences

We design studies around biologically defined patient groups, so a therapy that helps some people is not lost in an average.

Open about what doesn’t work

Negative results move the field forward too. We intend to share them.

About

Backed by the team behind Evalion.

Sequela Bio is funded by Voice Eval Systems, Inc., the company behind Evalion, the leading agentic operating system for clinical trials.

Evalion helps drug developers make better decisions while their trials are running. It understands each study’s protocol, medical and compliance rules, checks incoming data against them, and turns that data into near-real-time medical monitoring, early-phase decision support and ongoing trial oversight.

Sequela Bio puts that capability to work on one of the most important unsolved problems in medicine. Post-viral illness has frustrated researchers not only because the biology is complex, but because the trials meant to untangle it are hard to run well. That is the part Evalion was built for.

Why this makes sense

The hardest calls come early

In post-viral illness, the decisions that matter most are made in early studies: which patients to include, which signals to watch, and whether to expand, adjust or stop. Evalion was designed around exactly these early-phase decisions.

Seeing differences while a study runs

A trial built around patient subgroups only works if you can see how each subgroup is responding. Study-specific monitoring and visualization make those differences visible as data comes in, not months after a study ends.

Oversight built in from day one

Every check traces back to the protocol and the evidence behind it, so safety, quality and compliance are part of how a study runs rather than an audit after the fact.

More answers for the same effort

Lowering the cost and failure rate of trials means more promising ideas get tested. For conditions with no approved therapies, that can be the difference between a handful of attempts and many.

Learn more about Evalion

Team

Sequela Bio is in stealth. We’ll introduce our founders, scientific advisors and clinical partners soon.

Help us get this right.

We’re talking with researchers, clinicians, patient advocates and investors who believe post-viral illness deserves serious science.

Please don’t include personal medical information.