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What You Need to Know About the Coronavirus (COVID‑19) Pandemic

Course Number: 652

Risk Factors

Anyone can contract COVID‑19, but there are those that are more susceptible to developing increased symptom severity. This may be associated with co-morbid conditions and risk factors. Potential risk factors include age; race/ethnicity; sex or gender; some medical conditions; use of certain medications; poverty and crowding; certain occupations, and pregnancy.38 Others that may need to take special precautions are those that have risky individual situations, such at-risk racial and minority groups and those with disabilities.38 Also, those that live in care facilities/ group homes, or the homeless.39 The risk of developing serious symptoms increases with age, especially those 85 years of age or and older.39 In the U.S., about 80% of deaths from COVID‑19 have been in people age 65 and older, and the risks increase for older individuals with underlying health conditions.39 Existing lung issues, heart disease, diabetes, obesity, cancer, certain blood disorders, weakened immune systems, chronic kidney or liver disease place people at higher risk.39 There is a COVID‑19 Event Risk Assessment Planning Tool, which is a collaborative project led by Prof. Joshua Weitz and Prof. Clio Andris at the Georgia Institute of Technology, along with researchers at the Applied Bioinformatics Laboratory and Stanford University, and powered by RStudio. Description of the method and analyses available at Nature Human Behaviour.40

There has been some discussion that blood type may be a risk/protective factor regarding COVID‑19. One researcher stated that a higher proportion of COVID‑19 patients with blood group A or AB required mechanical ventilation and had a longer ICU stay compared with patients with blood group O or B. Blood types A and AB were also more apt to need a type of dialysis that helps the kidneys filter blood without too much pressure on the heart.41 In this study, blood group O was associated with a decreased risk for contracting SARS‑CoV‑2 infection.

Illustrated diagram showing percentages of COVID-19 cases for each blood type

Data sharing requests should be sent to Torben Barington (

There are important caveats to consider from this research. There is no indication that any blood type is either totally protective or increases the risk of a patient to severe outcomes of COVID‑19. The reason there is a concern regarding this issue is due to the biologic mechanism that might explain this interaction. Different blood types in patients are genetically inherited and have been linked to predisposing patients to cardiovascular diseases, cancers, and even susceptibility of COVID‑19. Studies have shown a relationship between blood types and increased severity of infection from COVID‑19 including increased risk of thrombosis.43