Content Library Longevity Journal

Dormant Viruses: How They Linger, Reactivate, and Affect Your Health

February 17, 2025

You might think a viral infection is behind you once you’ve recovered. But what if it never really left?

Some viruses—like Epstein-Barr, cytomegalovirus, and herpes viruses—don’t just disappear after the initial illness. Instead, they go into hiding inside your cells, lying dormant for months, years, or even a lifetime.

Most of the time, they stay quiet, kept in check by your immune system. But under certain conditions—like stress, another illness, or even a new viral infection (such as SARS-CoV-2, the virus that causes COVID-19)—these viruses can wake up and start causing problems all over again.

The result? A confusing set of symptoms—fatigue, brain fog, body aches—that can linger for weeks or months. Worse, these reactivated viruses can fuel chronic inflammation, accelerating aging and making it harder for your body to heal.

So what does this mean for your long-term health? And what can you do to keep dormant viruses from wreaking havoc?

Let’s take a closer look.

Dormant Viruses Are More Common Than You Think

Most people don’t realize they’re carrying dormant viruses—because they’ve never been tested for them.

Take Epstein-Barr virus (EBV), for example. Studies show that about 95 percent of adults have been exposed to it at some point, often in childhood.¹ For many, the virus stays inactive and never causes issues. But under the right conditions, it can reactivate and start interfering with your health.

This isn’t unusual. Dormant viruses are simply part of being human. The problem arises when they “wake up,” triggering immune dysfunction, inflammation, and lingering symptoms that can be hard to trace back to their source.

What Happens When Viruses Reactivate

A reactivated virus doesn’t just cause short-term symptoms—it can throw your immune system into a prolonged state of high alert.

Instead of shutting down the infection and moving on, your body stays locked in a defensive battle, fueling chronic inflammation and making recovery feel impossible.

Over time, this ongoing immune strain can wear you down, increasing the risk of autoimmune issues and long-term health implications.² Symptoms like brain fog, body aches, and exhaustion aren’t just frustrating—they’re signs that your immune system is struggling to restore balance.

Even mild viral infections can wake up dormant viruses, forcing your immune system into overdrive.

Research has linked SARS-CoV-2 to the reactivation of herpes viruses, including Epstein-Barr and human herpesvirus 6, particularly in people with post-viral conditions like Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Long COVID.³^,⁴

Other studies suggest viral infections can also disrupt cellular energy production, contributing to lingering fatigue, brain fog, and muscle weakness.

Latent Viruses and Long COVID

For some people, viral reactivation is more than just a temporary setback—it’s part of a larger pattern of lingering symptoms that don’t resolve. This is what seems to happen with Long COVID, where the body struggles to fully recover after a SARS-CoV-2 infection.

It’s not just about feeling “off” for a while. Many people with Long COVID experience extreme fatigue that doesn’t improve with rest, cognitive issues like brain fog, muscle aches, shortness of breath, and even unpredictable symptoms like heart palpitations or digestive problems.

Doctors have documented more than 200 possible symptoms of Long COVID, and they often come and go, making the condition difficult to diagnose and treat.

What’s causing all this?

Some researchers believe that reactivated viruses—like Epstein-Barr and HHV-6—could be a hidden driver of Long COVID symptoms, forcing the immune system into a prolonged battle.⁵ Others suggest lingering inflammation, tiny blood clots affecting circulation, or even persistent viral fragments continuing to disrupt the body’s systems.

The truth is, there’s still no universal consensus in the medical community. But one thing is clear: For many people, recovering from Long COVID isn’t just about getting past the initial infection—it’s about helping the body reset and regain balance.

Is a virus hiding inside of you?

Testing can uncover the hidden drivers of inflammation, including latent viruses that quietly stress your immune system over time.⁶

These biomarkers can act like clues, helping identify whether a lingering virus might be fueling inflammation and contributing to fatigue, cognitive decline, or other chronic health concerns.

By pinpointing these markers, you can better understand what’s impacting your body and take steps to restore balance and support your immune health.

How do you get tested? A Function Health membership gives you measures of 10 key biomarkers, listed below (plus, over 100 health biomarkers overall).

High-sensitivity C-reactive protein (hs-CRP): Detects low-grade inflammation that may indicate chronic infections or systemic inflammatory processes.⁷
White blood cell (WBC) count: Identifies immune system activity, which can increase with infections or inflammation.⁸
Lymphocytes, neutrophils, monocytes, eosinophils, and basophils: Assess immune response and identify patterns suggestive of viral, bacterial, or allergic triggers.⁹
Cortisol: This stress hormone has anti-inflammatory effects, but chronic stress or immune imbalances can cause levels to be abnormally high or low, potentially driving inflammation and contributing to conditions like fatigue or immune dysfunction.¹⁰
Ferritin: Elevated levels can act as an inflammatory marker often linked to chronic infections or inflammatory diseases¹¹
Homocysteine: Reflects systemic inflammation that may be elevated due to chronic infections and is linked to issues like cognitive decline, autoimmune conditions, and damage to the brain's protective barrier.¹²^,¹³
Vitamin D: Low levels can impair immune function, making the body more susceptible to latent infections.¹⁴
Omega-6 /Omega-3 ratio: An imbalanced ratio, often skewed toward excessive omega-6 fatty acids from a modern diet high in processed foods and refined carbohydrates, is associated with chronic low-grade inflammation and the body's ability to manage latent viral infections.¹⁵
Thyroid function (TSH, Free T3, and Free T4): Chronic viral infections often impact thyroid health.¹⁶ Monitoring thyroid function can help manage related symptoms like fatigue and weight changes.
Autoimmunity markers (Antinuclear antibodies (ANA) screen): Viruses like EBV are linked to certain autoimmune diseases, since the virus can trigger immune responses that may contribute to autoimmune activity in genetically predisposed individuals.¹⁷

If you want to get even more specific and deeper insights, there are several add-on tests you can choose from. Those include:

Epstein-Barr virus antibodies: Identifies past or reactivated Epstein-Barr virus, often linked to chronic fatigue or latent (hidden) viral activity.¹⁸
Cytomegalovirus antibodies (IgG, IgM): Screens for chronic or latent cytomegalovirus infections that may contribute to immune dysregulation.¹⁹
Herpesvirus 6 antibodies (IgG, IgM): Assesses potential reactivation of this virus, which has been linked to chronic fatigue syndrome.²⁰
Complement component C4a and matrix metalloproteinase-9 (MMP-9): Evaluates chronic inflammatory responses, which can occur due to persistent infections or exposure to toxins like those produced by mold.²¹
Extended autoimmunity: Latent viral infections can exacerbate the production of autoantibodies by promoting immune system hyperactivation and perpetuating inflammatory cycles.²²

So, Where Does This Leave You?

Dealing with viral reactivation, lingering inflammation, or unexplained post-viral symptoms can feel overwhelming—especially when there’s no one-size-fits-all solution. But recovery is possible.

By reducing inflammation, strengthening your immune system, and giving your body the right support, you can help break the cycle of persistent symptoms. While research is still evolving, one thing is clear: the way you eat, move, and rest has a profound impact on your body’s ability to heal.

(If Long COVID is your primary concern, I put together a comprehensive guide Comprehensive Guide to Long COVID Recovery that offers strategies to support your recovery through nutrition, lifestyle adjustments, and advanced therapeutics.)

Steps You Can Take Today

If your immune system is stuck in overdrive, the goal isn’t to fight harder—it’s to restore balance. That starts with reducing inflammation and supporting your body’s natural defenses.

1. Remove Inflammatory Foods

What you eat has a powerful impact on your immune function and recovery. Diets high in sugar, refined carbohydrates, and unhealthy fats fuel chronic inflammation, making it harder for your body to fight infections and heal properly.

Here’s where to start:

Eliminate ultra-processed foods: These are the ones most people call “junk foods.” They include cookies, ice cream, chips, candy, donuts, fried foods, soda (any kind), and any food that has lots of ingredients on the label.
Cut out sugar and starch: Too much sugar and starch can suppress your immune system and worsen viral infections.²³ Plus, constantly eating these foods keeps your blood sugar elevated, increasing whole-body inflammation.
Avoid alcohol. Alcohol can suppress your immune system and increase inflammation, which can exacerbate your symptoms and delay recovery. It can also deplete essential nutrients your body needs to heal, such as vitamins B and C, and can disrupt sleep, further compromising your health.

2. Eat More Flavonoid-Rich Foods

Flavonoids are natural compounds in plant-based foods that reduce inflammation and support immune function. Research suggests they may help counteract viral reactivation and oxidative stress.

Foods high in flavonoids include:

Kaempferol: Spinach, kale, dill, cabbage
Quercetin: Onions, broccoli, apples, berries, peppers
Hesperidin: Oranges, lemons, grapefruits
Oleuropein: Olives, extra virgin olive oil
Catechins: Green tea, black tea, dark chocolate
Lauric acid: Virgin coconut oil

3. Rest and Recover

Getting quality sleep, managing stress, and incorporating gentle movement can all help regulate immune function.

Aim for 7–9 hours of sleep each night to support healing.
Practice stress management techniques like deep breathing or meditation to lower inflammation.
Stay active, but don’t overdo it—light movement like walking can aid recovery without overtaxing your system.

There’s no magic fix, but small, consistent steps can help your body heal. The more you support your immune system and reduce inflammation, the better equipped you’ll be to regain energy, clarity, and long-term resilience.

References

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3. Apostolou E, Rizwan M, Moustardas P, Sjögren P, Bertilson BC, Bragée B, Polo O, Rosén A. Saliva antibody-fingerprint of reactivated latent viruses after mild/asymptomatic COVID-19 is unique in patients with myalgic-encephalomyelitis/chronic fatigue syndrome. Front Immunol. 2022 Oct 20;13:949787.

4. Perumal R, Shunmugam L, Naidoo K, Abdool Karim SS, Wilkins D, Garzino-Demo A, Brechot C, Parthasarathy S, Vahlne A, Nikolich JŽ. Long COVID: a review and proposed visualization of the complexity of long COVID. Front Immunol. 2023 Apr 20;14:1117464.

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18. Rasa S, Nora-Krukle Z, Henning N, Eliassen E, Shikova E, Harrer T, et al. Chronic viral infections in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). J Transl Med. 2018 Oct 1;16(1):268.

19. Gugliesi F, Pasquero S, Griffante G, Scutera S, Albano C, Pacheco SFC, et al. Human Cytomegalovirus and autoimmune diseases: Where are we? Viruses. 2021 Feb 8;13(2):260.

20. Mozhgani S-H, Rajabi F, Qurbani M, Erfani Y, Yaslianifard S, Moosavi A, et al. Human Herpesvirus 6 infection and risk of chronic fatigue syndrome: A systematic review and meta-analysis. Intervirology. 2022;65(1):49–57.

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