When clients first started coming to me with lingering fatigue, brain fog, dizziness, anxiety, and strange inflammatory symptoms after Covid, I knew something didn’t quite add up. They were told they had Long Covid, but the pattern felt familiar, almost identical to what I’d seen many times before with reactivated Epstein-Barr Virus (EBV).

My ‘aha moment ‘came in October 2022, when a Swedish study published in Frontiers in Immunology showed that even mild Covid infections could trigger the reactivation of latent viruses, including EBV. It confirmed what I had been observing clinically for months. I remember reading it and thinking, Finally! I wasn’t crazy after all!!.

Later, I discovered that an earlier American study, published in Pathogens in June 2021, had already identified a strong association between so-called Long-Covid and EBV reactivation. Together, these studies validated what many of us in functional medicine had long suspected, that persistent post-Covid symptoms might not be caused by the virus itself, but by the immune chaos it leaves behind.

Dormant Doesn’t Mean Harmless

Epstein-Barr Virus is one of the most common viruses in the world. Around 95 percent of adults carry it, usually without symptoms. It remains dormant, quietly residing in our cells, until the body becomes stressed, toxic, or immunologically overwhelmed. Then, it can “wake up”, not necessarily as an acute infection, but as a reactivation.

This subtle reactivation can cause exhaustion, muscle pain, sleep disturbances, anxiety, poor temperature regulation, and the mysterious “crashes” people describe after even minimal exertion. And often, it brings something else, a sudden surge of histamine sensitivity, where foods, smells, skincare, even supplements start triggering reactions that never used to happen. Clients often say, “I feel like I’m reacting to everything.” That heightened reactivity is the body’s signal that the immune system has shifted into overdrive.

In many people, this shift may have been triggered by the SARS-CoV-2 infection itself. The inflammatory response, oxidative stress, and immune chaos of Covid provide ideal conditions for EBV to reactivate. But I’ve also seen similar symptom clusters appear after vaccination, or other forms of strong immune stimulation, moments when the body is pushed into a heightened state of alert. For some, this activation seems to “wake up” dormant viruses like EBV, HHV-6, or even Varicella-zoster, the virus behind shingles.

It’s a reminder that latent doesn’t mean gone. When the immune system is under stress, these long-silent viruses can resurface. The mechanisms differ, but the outcome, fatigue, brain fog, rashes, nerve pain, and hypersensitivity, can look remarkably similar.

When the Environment Tips the Balance

What struck me most, as I analysed dozens of these panels, was how frequently EBV reactivation overlapped with mould exposure and environmental toxicity. These are not separate problems, they are interconnected stressors that shape immune resilience.

We have two main “arms” of immune defence. Intracellular immunity, often called the Th1 system, is led by T cells and natural killer cells that patrol what’s inside our cells. This is the arm responsible for keeping viruses like EBV or HHV-6 in check.

Extracellular immunity, on the other hand, the Th2 system, is antibody-driven and protects what’s outside the cells, defending us against bacteria, allergens, and parasites.

In a balanced body, Th1 and Th2 work like a “see-saw”, constantly communicating and adjusting to maintain harmony. But when the body is burdened by toxic exposure, chronic inflammation, or emotional stress, this balance can tip. If Th1 weakens, intracellular surveillance drops, and dormant viruses such as EBV can reactivate. If Th2 becomes dominant, the immune system shifts toward allergic-type responses, histamine release, and hypersensitivity to foods, chemicals, or supplements that never used to cause problems.

This imbalance, a weakened Th1 and an overactive Th2, is something I see frequently in clients with so-called Long-Covid and chronic fatigue patterns. The immune system, now distracted and dysregulated, begins to attack not only the virus but sometimes its own tissues, leading to the neurological and inflammatory symptoms we see so often.

Seeing What Was Once Invisible

For years before these panels were even available in the UK, I remember listening to Dr Tom O’Bryan at conferences in London, speaking passionately about a new era of precision antibody testing. At the time, it felt like we were hearing about the future technology that existed but was still just beyond our reach here. When the tests finally arrived several years later, everything I’d learnt from Dr Tom’s lectures came to life in practice. I’ve had the privilege of working alongside him, reviewing hundreds of panels for our patients, and seeing how this level of precision can transform complex cases. I truly learnt from the best, and those experiences continue to shape how I interpret results today.

Among the tools I use, neuro-immune antibody panel such as the Neural Zoomer Plus allows me to look beyond standard blood markers and explore immune activity at the level of the brain and nervous system. In simple terms, it helps identify what may be invisibly attacking your brain, long before those immune reactions translate into noticeable symptoms. For viruses such as Epstein-Barr, the test looks at several distinct antigens, including EBNA-1, VCA gp125, EA antigen, p18, and p23, giving a much clearer picture of how active the immune system is against different stages of the virus. When these antibodies run high, it tells us the immune system is no longer just keeping EBV dormant; it’s engaging with it again.

Client after client who came to me with so-called Long-Covid symptoms showed off-the-chart EBV antibody activity, often alongside immune responses to HHV-6, dopamine and serotonin receptors, or strep A and tubulin, patterns that reflect immune cross-talk between infection, inflammation, and the nervous system. This test didn’t just confirm my suspicions; it transformed the way I practise. It allowed me to see what was previously invisible, that these symptoms weren’t random, and they certainly weren’t “all in the head.”

What’s truly remarkable about this technology is its ability to detect neuro-immune activity long before major symptoms appear. Even subtle changes – a dip in mood, occasional forgetfulness, that “brain fog” you brush off as tiredness, can sometimes reflect early immune activity in the brain. How amazing and empowering is it to know what’s happening before it turns into something bigger? To catch the earliest signs of inflammation or antibody activity and support your body before it starts sending louder distress signals.

For me, this is the future of functional medicine, using early, high-resolution testing not just to explain illness, but to prevent it. The panel offers a window into your brain’s immune landscape, helping you understand what’s quietly shaping your focus, memory, mood, and resilience long before you might notice anything overt. This kind of insight is deeply empowering. It moves us from guessing and symptom-chasing to truly personalised prevention, giving you the information you need to protect your most valuable organ: your brain.

I also use the lab’s Environmental Toxins, Heavy metals and Mycotoxin panels, which I find to be the most detailed on the market. Together, these tests have been genuine game-changers in my practice, helping me connect the dots between toxicity, immune imbalance, and viral reactivation in ways that standard labs simply can’t.

A Functional Medicine Approach: Restoring the Terrain

The good news is that once we understand the pattern, we can begin to rebuild the body’s resilience. My approach focuses on five key pillars:

1. Reducing exposure to mould and toxins – identifying and removing environmental triggers that perpetuate immune activation and overload detox capacity.
2. Repairing gut and mucosal immunity – restoring the first line of defence that regulates immune tolerance, nutrient absorption, and histamine balance.
3. Supporting detoxification and liver function – using targeted nutrients and botanicals to enhance clearance of viral and environmental by-products.
4. Calming neuroinflammation – through antioxidant and anti-inflammatory support for the brain and nervous system to restore clarity and mood stability.
5. Rebuilding mitochondrial energy – because cellular energy is the foundation of long-term immune recovery, vitality, and cognitive function.

This isn’t about “killing” viruses; it’s about creating the right internal environment, so they stay quiet. When the terrain is healthy, the immune system remembers what to do.

The Bigger Picture and Hope

If you’ve been told you have Long Covid but the label doesn’t quite fit, or if you’ve been living with unexplained fatigue, brain fog, or sensitivity since your infection, you are not alone and… most importantly, you are not imagining it. The science now supports what many of us in functional medicine have observed for years: dormant viruses like EBV can reactivate under toxic and inflammatory stress, creating a cascade of symptoms that conventional testing simply doesn’t detect.

With advanced functional testing we can finally uncover the hidden layers driving those symptoms and design a personalised plan to help your body recover balance, clarity, and vitality. Because here’s the truth: this is all addressable. Once we understand why the immune system lost its balance, we can help it remember how to find homeostasis again.

Ready to get to the root of your symptoms?

Book your complimentary Discovery Call to explore how advanced testing and functional nutrition can help you understand what’s really going on and start feeling like yourself again.