- [Narrator] In a healthy body, blood vessels carry oxygen-rich blood to organs throughout the body.

When a blood vessel is injured, a blood clot helps repair the leak and prevents bleeding.

Infection or damage to the inner lining of the blood vessel can also trigger clotting.

COVID-19 is a disease caused by a virus called SARS-CoV-2.

While the virus can cause serious lung disease, it can also affect many other parts of the body.

Some people with COVID-19 develop abnormal blood clots, including lots of tiny clots in the smallest blood vessels.

The clots may form in multiple places throughout the body including the lungs.

This unusual clotting, one of many mysteries associated with the disease, may cause different complications, from organ damage to heart attack and stroke.

People who already have damage to the blood vessels from diabetes or high blood pressure may be at higher risk of developing blood clots if they are infected with the virus.

Researchers think the clotting may be triggered by the high levels of inflammation caused by the SARS-CoV-2 infection.

The high inflammation levels can damage multiple organs and result in severe disease.

In children and teens, this is called Multisystem Inflammatory Syndrome, and it can particularly affect the heart.

NHLBI is also supporting new studies, including clinical trials, focused on developing safe and effective treatments for people infected with SARS-CoV-2.

People with chronic lung, heart, or blood diseases may be at higher risk of severe illness from COVID-19.

We should all take steps to help protect ourselves and others from infection by washing hands often, avoiding crowded places, wearing a mask, and staying at least six feet from other people.

Visit our website for the latest information and resources on COVID-19.

(bright music)