How does COVID-19 affect the blood?
Some people with COVID-19 develop abnormal blood clots, including in the smallest blood vessels. The clots may also form in multiple places in the body, including in the lungs. This unusual clotting may cause different complications, including organ damage, heart attack and stroke.
Researchers think the clotting may be triggered by the high levels of inflammation caused by the SARS-CoV-2 infection. A high level of inflammation can affect multiple organs and result in severe disease. In children and teens, this high inflammation is called multisystem inflammatory syndrome (MIS-C), and it can particularly affect the heart.
What health conditions may impact how COVID-19 affects my blood?
People who already have damage to the blood vessels from diabetes or high blood pressure may be at higher risk of developing blood clots. In addition, some chronic health conditions may impact how COVID-19 affects your body, including your blood vessels. These include:
- Coronary artery disease
- Diabetes
- High blood pressure
- Pulmonary hypertension
- Obesity
- Sickle cell disease
- Thalassemias
Check CDC’s page on higher risk groups for more information on existing medical conditions and COVID-19.
What is the NHLBI doing to support research on how COVID-19 affects the blood?
NHLBI-funded research has helped us understand how inflammation and infection affect the blood.
- Blood thinners and COVID: The findings guiding patient care
- Scientists pinpoint mechanisms associated with severe COVID-19 blood clotting
- Advancing blood research to help patients recover from COVID-19
- Immune signaling sequence explains some severe COVID-19 cases
- NIH scientists discover key pathway in lysosomes that coronaviruses use to exit cells
- COVID-19 posing grim challenge for sickle cell disease patients
- Arterial wall cells offer insight into coronavirus’ rampage from head to toe
- Potential cause behind blood clotting in COVID-19 patients uncovered
The NHLBI also supports new research, including clinical trials that are focused on developing treatments for people infected with SARS-CoV-2.
- NIH study shows no significant benefit of convalescent plasma for COVID-19 outpatients with early symptoms
- Full-dose blood thinners reduce the need for organ support in moderately ill COVID-19 patients, but not in critically ill patients
- U.S. blood donations are safe under current COVID-19 screening guidelines
- Statement on NIH starting enrollment for third trial of blood clotting treatments for COVID-19
- Hydroxychloroquine does not benefit adults hospitalized with COVID-19
- Special test detects who’s at risk for life-threatening blood clots from COVID-19
- Can treatment for a rare blood disorder offset extreme immune responses to COVID-19?
- NIH ACTIV initiative launches adaptive clinical trials of blood clotting treatments for COVID-19
- Novel blood filter approved by FDA for emergency treatment of COVID-19
What can I do to keep myself and others safe?
Getting a COVID-19 vaccine can protect you from COVID-19. Wearing a mask indoors, washing your hands often, and staying at least 6 feet from other people can also help protect you and possibly prevent spreading the virus to others. The Centers for Disease Control and Prevention (CDC) provides up-to-date information on how to protect yourself and othersexternal link.
In addition, consider:
- Find COVID-19 treatment information from the Administration for Strategic Preparedness & Response.external link
- See all COVID-19 clinical studiesexternal link.
Be sure to check these additional COVID-19 information sources from the U.S. Department of Health and Human Services: