COVID-19 is a complex disease caused by the coronavirus, which attacks the body in a variety of ways that are still under investigation. The virus affects various organs and tissues, including the blood, with mild to severe symptoms.
People with anemia have a higher chance of developing long-term symptoms of COVID-19 infection even after the virus has cleared the body. Anemia is a clinical signature of these symptoms, generally appearing after a few weeks or months following the initial infection. COVID-19 patients develop inflammation that causes a reduction in intestinal iron absorption and changes in iron hemostasis, resulting in reduced production of hemoglobin.
Anemic patients can develop severe outcomes of COVID-19, including ICU admission, ventilator need, and death. Anemia affects the body's immunity, increasing the probability of these outcomes in COVID-19 patients.
In addition, anemia activates the body's sympathetic nervous system, leading to increased heart rate, pulmonary capillary leakage, and high blood pressure, which causes acute respiratory distress syndrome (ARDS). A patient with COVID-19 ARDS develops worse outcomes than typical ARDS, often resulting in respiratory failure, circulatory failure, and myocardial damage.
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Anemia is a disease that occurs when the blood does not have enough healthy red blood cells to circulate oxygen throughout the body. Red blood cells contain hemoglobin, a protein responsible for transporting and delivering oxygen to organs and tissues.
Having anemia means your hemoglobin levels are low, and your body is not getting enough oxygen. Without oxygen, the body lacks the energy needed to function, which causes symptoms like shortness of breath and fatigue.
Anemia has many causes and can either be a short-term or long-term condition. If left untreated, anemia has severe symptoms that may become life-threatening.
In a COVID-19 infection, the coronavirus attacks and damages the membrane proteins in the red blood cells. These membranes provide the red blood cell structure, which allows the cells to regulate oxygen release capacity and move smoothly through the capillaries and bloodstream.
As a COVID-19 patient with damaged red blood cells, you are more likely to develop blood-related disorders like anemia. When the virus attacks the red blood cells, it may take a while before the body clears and replaces damaged cells with healthy ones, leading to anemia.
Anemia has many different types, each with its specific causes. These include:
Iron deficiency anemia. It occurs due to an iron shortage in the body. Without enough iron, the body cannot produce sufficient hemoglobin, affecting oxygen circulation.
Vitamin deficiency anemia. Your body requires vitamin B-12 and folate to produce healthy red blood cells. Consuming a diet that lacks these nutrients may cause a decrease in red blood cell production.
Anemia of inflammation. Chronic inflammatory diseases like cancer, arthritis, Crohn's disease, and kidney disease interfere with red blood cell production.
Aplastic anemia. It is a rare type of anemia caused by certain medications, autoimmune diseases, infections, and exposure to toxic substances.
Hemolytic anemia. It develops as a result of red blood cells being destroyed faster than the bone marrow replaces them. Blood diseases often cause the increased destruction of red blood cells. Hemolytic anemia is inherited or may develop later in life.
Sickle cell anemia. It occurs when the body produces crescent or sickle-shaped red blood cells. The defective blood cells have a short life span and die fast, which causes a reduction in red blood cells.
Anemia from bone marrow disease. Diseases such as myelofibrosis and leukemia affect red blood cell production in the bone marrow, which causes anemia. The effects resulting from such cancer-like diseases vary from mild to severe.
Megaloblastic anemia. It results when red blood cells become very large and are released before maturity. The red blood cells have a low count due to improper multiplication during production.
The exact pathophysiology of COVID-19 and anemia is not fully understood, and as a result, several potential mechanisms have been proposed. At first, COVID-19 infection was termed an infectious-inflammatory disease that affects the lungs. As the COVID-19 pandemic progressed, it became more apparent that the coronavirus affects the lungs and other organs, with various injury pathways.
One pathophysiology mechanism suggests that the coronavirus (SARS-CoV-2) can worsen anemia in some patients when it interacts with hemoglobin, specifically its interaction with receptors in the blood cell precursors. Such an interaction has the coronavirus attacking the heme (part of hemoglobin containing iron), which subsequently causes hemolytic anemia.
Another pathophysiology mechanism suggests that a spike protein on the coronavirus surface induces iron deficiency, reduces functioning hemoglobin, and causes hyperferritinemia. The excess circulation of the iron-storage protein ferritin in the body characterizes hyperferritinemia. The disorder causes the release of toxic heme, leading to ferroptosis (tissue death from iron dependence). The subsequent oxidative stress may cause an autoimmune over-response, which triggers inflammation, leading to severe COVID-19 outcomes. Anemic hypoxia may occur due to the defect in the hemoglobin molecules and the increased coagulation activity.
Vaccination is the most effective way to prevent severe symptoms and fatalities related to COVID-19. During the pandemic, pharmaceutical companies developed and tested vaccines against the disease. A vaccination strategy was later developed to make the vaccines available to the public.
Vaccines usually have side effects that must be reported to the concerned authorities to allow investigations on the risks and benefits and how to act when they occur. The COVID-19 mRNA vaccine may cause autoimmune hemolytic anemia, characterized by the body's immune system destroying red blood cells.
COVID-19 hemolytic anemia has related acute infections that may have underlying autoimmune, infectious, lymphoproliferative, or neoplastic diseases. Pharmaceutical companies have reported some cases of hemolytic anemia resulting from vaccines. Hemolytic anemia is often described as an adverse reaction to viral vaccines like influenza. One mechanism proposes that a secondary autoimmune response through mimicry of the body's antigens by viral peptides causes cross-activation in the autoreactive cells.
Corticosteroid therapy is the first line of treatment for COVID-19 patients with hemolytic anemia because it suppresses hemolysis and increases hemoglobin levels.
Treatment for post-COVID anemia depends on the cause and severity. People who experience mild anemia symptoms may not require any treatment.
Anemia caused by health conditions like COVID-19 or medicines requires a change in treatment to stop or manage the condition. A doctor will prescribe medication to promote the production of red blood cells in the bone marrow. Symptomatic anemia is often treated using steroids, but if the treatment fails to work, a splenectomy may be performed since the destruction of red blood cells mainly occurs in the spleen.
You may require immunosuppressant medications for autoimmune hemolytic anemia when splenectomy is inappropriate or does not work. These medicines suppress the immune system and stop post-COVID inflammation. However, immunosuppressants leave the body vulnerable to other infections, and patients may become sick more often due to the treatment. Your doctor weighs up the benefits and risks before prescribing treatment with such drugs.
Anemia is common and persistent in COVID-19 patients during treatment and recovery. It affects the quality of life and should not be overlooked but investigated and treated. COVID-19 anemia is a predictable illness with severe symptoms that needs comprehensive management and proper treatment.
Anemia is a condition that is an independent risk factor for severe outcomes of COVID-19. The condition is manageable with proper treatment to avoid future complications.
Hemolytic anemia is a potential side effect of COVID-19 vaccines like the mRNA vaccine. The condition is symptomatic, and the person requires medical care.
Aplastic anemia is a rare type resulting from the immune-mediated failure of the bone marrow. COVID-19 infection significantly causes the body to be immunosuppressed, which can lead to aplastic anemia.
Membrane proteins (2002)
Hemolytic anemia (2023)
Autoimmune hemolytic anemia | Rare Disease