COVID’s Effect on the Brain, Gut, and the Role of the Epstein-Barr Virus

July 21, 2023

A paper recently released in Nature: Molecular Psychiatry presents current thinking on the mechanisms behind potential Long Covid treatments. Some of the most common and debilitating symptoms of Long Covid are neurological or psychiatric. Several studies have shown that the COVID-19 virus can cross the blood-brain barrier and enter the brain (1) (2) (3) (4). Covid infection of the brain has been shown to lead to structural changes and neuroinflammation which could be responsible for the persistent neurological and psychiatric symptoms. One study found that damage to the olfactory cortex of COVID-19 survivors was associated with loss of taste and smell. But viral presence in the brain does not explain all symptoms.

Researchers have found evidence of COVID-19 reactivating Epstein-Barr Virus (EBV) causing more severe illness and persistent symptoms of fatigue and cognitive impairment (5) (6) (7) (8). The drug fluvoxamine is being studied as a potential treatment to block the reactivation of EBV and has shown promise for preventing fatigue in Long Covid.

Another area of ongoing research is disruption in the microbiome caused by COVID-19 infection. Viral particles are known to persist in the gut for up to four months after recovery (9) (10), and persistent gastrointestinal symptoms have been associated with changes in the gut microbiome of COVID-19 patients even after recovery (11) (12) (13) (14). Additional research found a reduction in anti-inflammatory microbes in the guts of such patients. The COVID-19 virus may also be damaging the lining of the intestinal tract leading to intestinal symptoms. Outside the gut, changes in the nasal microbiota have been associated with loss of smell in COVID-19 patients, and research in rodent models suggests that lung microbes may also play a role (15) (16).

Current research on treatment and prevention of both acute infection and Long Covid is underway, including:

  • Implementing plant-based and vegetarian diets was shown to reduce the risk of infection and COVID-19 severity, especially in elderly populations.
  • Supplementation with probiotics showed improved outcomes for patients with acute COVID-19 and was suggested as a treatment for Long Covid (17) (18) (19).
  • Short-chain fatty acid butyrate and the use of fecal microbial transplants have been suggested as means of improving intestinal dysbiosis during and after COVID-19 infection, but more research is needed to determine their efficacy.
  • Vagus nerve stimulation, which has several clinical trials underway. Similarly used to treat refractory epilepsy and depression, vagus nerve stimulation is thought to treat systemic inflammation from Long Covid.

While a comprehensive understanding of COVID-19 and Long Covid is still a long way off, current research suggests that multiple pathways are involved, and many different treatments may be effective.