You recover from COVID-19, yet something still feels “off.” Fatigue lingers, everyday tasks feel harder, or symptoms seem to return in waves. Could the immune system be dealing with more than one virus?
A major study suggests that severe COVID-19 may reactivate viruses that have remained quiet inside the body for years. The finding offers an intriguing new piece of the long COVID puzzle—but it does not prove that these dormant viruses cause persistent symptoms.
Here is what researchers discovered, what remains uncertain, and how to support recovery without falling for unproven “immune-boosting” remedies.
What Does Viral Reactivation Mean?
Some viruses do not completely leave the body after the original infection resolves. Instead, they enter a quiet or latent state inside certain cells.
The immune system usually keeps them under control. However, serious illness, major stress, surgery, sleep deprivation, immune-suppressing medication, and other physical strains may sometimes allow a virus to become active again.
Familiar examples include:
- Epstein-Barr virus (EBV), which can cause mononucleosis
- Cytomegalovirus (CMV)
- Herpes simplex virus type 1 (HSV-1)
- Varicella-zoster virus, which can later reappear as shingles
Reactivation does not always produce obvious symptoms. In some cases, it is detectable only through specialized laboratory testing.
What the Major COVID-19 Study Found
Researchers followed 1,154 adults hospitalized with COVID-19 at 20 hospitals across the United States. They repeatedly examined blood, nasal samples, and—when available—fluid from the respiratory tract during hospitalization and recovery.
The scientists searched for viral genetic activity rather than relying only on antibodies from past infections.
Among 1,148 participants included in the relevant analysis, approximately 48% had evidence that at least one persistent virus had become active within 40 days of hospitalization. Most of those patients had only one reactivated virus detected.
The most notable findings involved viruses from two families:
- Herpesviridae, including EBV, CMV, and HSV-1
- Anelloviridae, a widespread but poorly understood group of viruses
Different viruses followed different timelines. EBV and anelloviruses appeared more often early in the illness, while CMV and HSV-1 generally peaked later. Viral activity was also associated with distinctive immune, inflammatory, and metabolic changes.
The findings were published in Nature.
Why Severe COVID-19 May Wake Up Other Viruses
The immune system has limited resources. During a major infection, it must coordinate inflammation, destroy infected cells, produce antibodies, and repair damaged tissue.
One possibility is that this intense workload temporarily weakens the immune surveillance that normally keeps persistent viruses quiet. Researchers sometimes compare this to security guards being redirected toward an emergency, leaving another entrance less protected.
Reactivated viruses may then add another layer of immune activity and inflammation. However, this relationship could work in several directions:
- Severe COVID-19 might trigger viral reactivation.
- Reactivated viruses might contribute to a more complicated illness.
- Both might reflect an immune system under extreme stress.
- Some reactivations may be biological bystanders rather than drivers of disease.
The study identified associations, not definitive cause and effect.
Could Dormant Viruses Be Connected to Long COVID?
Long COVID can involve fatigue, shortness of breath, brain fog, sleep disruption, pain, post-exertional symptom worsening, and difficulty completing ordinary activities.
Researchers found that persistent anellovirus activity was associated with a group of participants reporting ongoing physical limitations. This association remained after accounting for factors such as age, initial COVID-19 severity, sex, and immune-suppressing medication.
That is scientifically interesting, but it does not establish that anelloviruses caused the disability. These viruses are found in a large proportion of the population, and their role in human disease remains uncertain.
The study also observed extensive EBV reactivation during severe acute COVID-19. Previous research has connected altered EBV antibody patterns with long COVID, but the new study did not find that acute EBV activity alone reliably predicted who would develop long-term symptoms.
For now, viral reactivation should be viewed as one possible part of a much larger picture that may also involve inflammation, immune dysregulation, blood-vessel changes, nervous-system effects, and viral persistence.
Important Limits of the Research
The results should not be applied to every person who has had COVID-19.
Participants were hospitalized between May 2020 and March 2021. They were unvaccinated and primarily infected with early SARS-CoV-2 strains. Many experienced moderate, severe, or critical illness.
Researchers still need to determine whether similar patterns occur in:
- People with mild or asymptomatic infections
- Vaccinated individuals
- People with hybrid immunity from vaccination and prior infection
- Children and adolescents
- Those infected with newer variants
The researchers also examined only selected body tissues, so some viral activity may have been missed. Participant dropout during follow-up limited parts of the long COVID analysis.
Most importantly, the study does not show that everyone with post-COVID fatigue has EBV, CMV, herpes, or another reactivated virus.
Should You Request Tests for Dormant Viruses?
Testing should be guided by symptoms, medical history, and a clinician’s assessment—not ordered automatically after every COVID-19 infection.
Standard antibody results can also be misunderstood. For example, certain EBV antibodies may remain positive for life and simply indicate a past infection. They do not necessarily prove current viral reactivation.
Speak with a healthcare professional if symptoms persist, worsen, or interfere with daily activities, particularly if you experience:
- Severe or unusual fatigue
- Recurrent fever
- Swollen lymph nodes
- A painful blistering rash
- Persistent shortness of breath
- New neurological symptoms
- Unexplained weakness or significant decline in function
Seek urgent medical attention for difficulty breathing, persistent chest pain or pressure, confusion, fainting, blue or gray lips, or sudden one-sided weakness.
A Gentle, Evidence-Aware Recovery Routine
No food, herb, or supplement has been proven to force a latent virus back into dormancy. Recovery support should focus on reducing unnecessary strain and meeting the body’s basic needs.
Pace Your Activity
If physical or mental effort causes symptoms to worsen hours later or the following day, pushing through may backfire. Break tasks into smaller pieces, schedule rest before exhaustion, and increase activity gradually only when your body tolerates it.
Build Meals Around Recovery
Aim for regular meals containing:
- Protein from eggs, fish, poultry, yogurt, tofu, beans, or lentils
- Colorful vegetables and fruit
- Healthy fats from olive oil, nuts, seeds, and avocado
- Fiber-rich carbohydrates such as oats, brown rice, potatoes, and legumes
- Enough water and electrolytes when appropriate
There is no need for a restrictive “antiviral cleanse.” Undereating may make fatigue, dizziness, and weakness worse.
Protect Sleep and Nervous-System Calm
A consistent sleep schedule, morning daylight, reduced evening screen exposure, and several minutes of slow breathing may help the body settle into a steadier rhythm.
A simple exercise is to inhale gently for four counts and exhale for six, repeating without forcing the breath.
Use Herbs for Comfort, Not as a Cure
Traditional herbal practices may offer gentle symptom support:
- Ginger tea may soothe nausea and support comfortable digestion.
- Chamomile tea is traditionally used for relaxation and sleep.
- Lemon balm tea may provide mild calming support.
- Peppermint tea may ease digestive discomfort, although it can aggravate reflux.
These herbs do not eliminate SARS-CoV-2, EBV, CMV, HSV, or long COVID.
Pregnant or breastfeeding people, children, anyone taking medication, and people with chronic health conditions should consult a qualified healthcare professional before using concentrated herbal extracts or supplements. Ginger may interact with blood-thinning medication, chamomile may trigger reactions in people allergic to ragweed-family plants, and lemon balm may not be appropriate with certain thyroid or sedative medicines.
Be Cautious With “Immune-Boosting” Protocols
More immune stimulation is not automatically better. Some post-viral problems may involve poorly regulated immune activity rather than a simply “weak” immune system.
Avoid high-dose supplements, multiple herbal tinctures, prescription antivirals obtained without medical supervision, and online protocols claiming to eradicate latent viruses. Antiviral medications are virus-specific and may require testing, monitoring, and careful attention to side effects.
A balanced approach is quieter but safer: nourish the body, protect sleep, avoid overexertion, manage existing conditions, and seek medical care when symptoms persist.
The Bottom Line
The latest research suggests that severe COVID-19 can coincide with the reactivation of viruses already living quietly in the body. Almost half of the hospitalized participants showed evidence of at least one viral reactivation, and certain patterns were associated with illness severity or later physical limitations.
That does not mean dormant viruses are the single cause of long COVID—or that everyone who had COVID-19 should be tested or treated for them. It means researchers have identified another promising path toward understanding why recovery can be so different from one person to another.
Save this article for your recovery notes, and share your experience if you noticed unexpected or lingering symptoms after COVID-19.
