On Jul. 5, 2022, the National Institutes of Health released a study that described the immune response triggered by COVID-19 infection that damages the brain’s blood vessels and may lead to short- and long-term neurological symptoms. In a study published in Brain, researchers from the National Institute of Neurological Disorders and Stroke (NINDS) examined brain changes in nine people who died suddenly after contracting the virus.

The scientists found evidence that antibodies-proteins produced by the immune system in response to viruses and other invaders-are involved in an attack on the cells lining the brainﾒs blood vessels, leading to inflammation and damage.

Understanding how SARS-CoV-2 can trigger brain damage may help inform development of therapies for COVID-19 patients who have lingering neurological symptoms.

For the first time, researchers observed deposits of immune complexes—molecules formed when antibodies bind antigens (foreign substances)—on the surface of endothelial cells in the brains of COVID-19 patients. Such immune complexes can damage tissue by triggering inflammation.

The study builds on their previous research, which found evidence of brain damage caused by thinning and leaky blood vessels. They suspected that the damage may have been due to the body’s natural inflammatory response to the virus.