COVID-19 can leave a trail of consequences that last over time. Science is still discovering the long-term health effects of the disease. Now, a new study of 24 patients has revealed that the SARS-CoV-2 virus causes changes in immune system cells in different parts of the body.

According to research by the University of California, CellSight Technologies, and Kaiser Permanente South San Francisco Medical Center, the effect is widespread and silent.

The immune system suffers from a wide-ranging impact.

• PET (positron emission tomography) scans reveal alarming images of the entire body of patients with COVID-19.
• The researchers discovered abnormal activity of T cells – from the immune system – in the brain stem, spinal cord, bone tissue, nose and throat, heart tissue, lung tissue and intestinal wall.
• Of the 24 volunteers, 6 fully recovered from the most severe stage of the disease and 18 developed symptoms of long Covid.
• The impact on some parts of the body, such as the spinal cord and gut wall, was greater in long-term Covid patients.
• But even those who recovered completely had persistent changes in T-cell activity in multiple organs for up to two and a half years.
• Although the study is not conclusive, it suggests that the persistence of symptoms may be linked to the virus's effect on the immune system.

But what could these changes mean?

To better understand, imagine that the little soldiers in your body are undergoing changes that weaken them. Without this balanced and strong defense system, the body may not be able to fully heal itself from the effects of disease or become more vulnerable to invaders.

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The continuing effects of long Covid

Long Covid is a condition characterised by a range of symptoms that persist after an initial infection with SARS-CoV-2, without any other known cause. Diagnosis is challenging, with more than 200 possible symptoms such as “mental confusion,” fatigue and diarrhoea, which can overlap with other illnesses.

The disease can affect multiple organs, including the heart, brain, lungs, and more. Autopsies conducted in previous studies have also revealed that the virus can persist in different parts of the body for months.

There is also evidence that SARS-CoV-2 can reactivate other dormant viruses, such as Epstein-Barr, which is associated with chronic fatigue syndrome (CFS). Other studies suggest that long COVID and CFS share many symptoms and may be the same condition.

These findings highlight the need for further research to fully understand the lingering effects of COVID-19. Details of the study were published in Translational Medicine Sciences.