Severe COVID-19: Symptoms, Risk Factors & Prevention (2024)

Age is the most significant risk factor for severe COVID-19 outcomes, and the risk of severe outcomes increases greatly with increased age.⁵ The risk of severe COVID-19 also increases with the addition of some medical conditions, which can occur in older adults.^2,5 Based on data from February 2020 to July 2022, the risk of dying from COVID-19 is approximately 25 times greater if you’re 50-64 years old and 60 times greater if you’re 65-74 years old compared to adults 18-29 years old.⁵

Having cancer, or being treated for cancer, can weaken the body’s ability to fight illnesses, increasing the risk for severe COVID-19.² Being diagnosed with COVID-19 while having cancer can double the chance of being hospitalized, needing intensive care, or requiring a machine to assist with breathing compared to a person without cancer.^6,7

Having any stage of chronic kidney disease (CKD), or being treated for CKD, can increase the risk for severe COVID-19 due to worsening kidney function.^2,8 For example, being on dialysis—a treatment that helps the body remove waste products and fluid from the blood when the kidneys are unable to—is associated with a higher risk of death from a COVID-19 infection.^9,10

Having chronic liver disease, including but not limited to alcohol-related liver disease, non-alcoholic fatty liver disease, autoimmune hepatitis, and cirrhosis, can weaken the body’s immune system, increasing the risk for severe COVID-19.^2,11 It can also lead to an acute rise in liver enzymes, increasing the severity of COVID-19.¹¹

Having chronic lung disease, including but not limited to asthma, bronchiectasis, chronic obstructive pulmonary disease (COPD), interstitial lung disease, pulmonary embolism, and pulmonary hypertension, can impair lung function and increase the risk for severe COVID-19.^2,12,13

Having cystic fibrosis may increase the risk for severe COVID-19 due to decreased lung function and potentially weakened immune systems.^2,14,15

Having dementia can increase the risk for severe COVID-19 due to comorbidities such as a weakened immune system, heart or blood vessel disease, diabetes, and older age.^2,16

Having Type 1 or Type 2 diabetes can increase the risk for severe COVID-19.^1,2 This is because diabetes is characterized by high blood sugar, which both compromises the immune system and helps the virus thrive and multiply.^{2,17,18,19,20}

Having disabilities such as attention-deficit/hyperactivity disorder (ADHD), cerebral palsy, birth defects, intellectual and developmental disabilities, learning disabilities, spinal cord injuries, Down syndrome, or other disabilities that make it more difficult to do certain activities places individuals at higher risk for severe COVID-19 due to “underlying medical conditions, congregate living settings, or systemic health and social inequalities.”^2,21,22

Having heart conditions such as heart failure, cardiomyopathies, coronary artery disease, or possibly high blood pressure (hypertension) can increase the risk for severe COVID-19.^2,20

Having HIV can increase the risk for severe COVID-19 due to a potentially weakened immune system and other potential comorbidities.^2,23 Approximately 50% of people with HIV in the United States are older than age 50, putting them at greater risk of severe COVID-19, and many have one or more comorbidities or conditions that may also put them at higher risk of severe COVID-19.²⁴

Being immunocompromised or having a weakened immune system due to a medical condition or a treatment for a medical condition can increase the risk of severe COVID-19, as it makes the body less able to protect itself from infection.²

Having mood disorders, including depression and schizophrenia spectrum disorders, may increase the risk of severe COVID-19 due to a variety of factors, such as “barriers to access to care, social determinants of health, immunological disturbances, and the effects of psychotropic drugs.”^2,25,26

Obesity can triple the risk of being hospitalized from COVID-19.²⁷ Obesity can make breathing even more difficult when diagnosed with COVID-19, and immune systems can be weaker, increasing the risk of ending up in the intensive care unit (ICU), needing a ventilator to breathe, or dying.^2,28,29 Being overweight can also increase the risk for severe COVID-19.^2,29

Engaging in little or no physical activity can increase the risk of severe COVID-19, as there are likely comorbidities at play, such as being overweight or having obesity and a greater risk of diabetes. Research has found that any amount of physical activity could help prevent severe COVID-19, though best practices to avoid severe illness from COVID-19 include meeting the U.S. physical activity guidelines (adults should engage in at least 150 minutes of physical activity per week).^2,30

Being pregnant, or recently pregnant (within 42 days from the end of pregnancy), can increase the risk for severe COVID-19 due to changes that occur in the body, including weakened immune systems that make those who are experiencing pregnancy more vulnerable to illnesses.^2,31 Getting COVID-19 while pregnant can also make it more difficult to breath and increase the risk for blood clots.³²

Having sickle cell disease (SCD) may increase the risk for severe COVID-19.^2,33 In the United States, SCD-related deaths were stable from 2014 to 2019 but increased 12% in 2020 during the height of the COVID-19 pandemic.^2,33

Being a current or former cigarette smoker can increase the risk for severe COVID-19. Smoking damages the lungs and can affect other organs of the body. COVID-19 primarily attacks the respiratory system and lungs; therefore, smokers are exposed to a greater risk of getting severe COVID-19 symptoms.^2,34

Having had a solid organ or blood stem cell transplant, including bone marrow transplants, can increase the risk for severe COVID-19 due to potential comorbidities and a weakened immune system from the transplant and/or chronic immunosuppressive therapy.^2,35

Having cerebrovascular disease, including stroke, can increase the risk for severe COVID-19. This may be because the lack of blood flow to the brain that occurs with a stroke can weaken the ability of the immune cells in the lungs that respond to bacteria and viruses.^2,36 Getting COVID-19 after having had a stroke can increase the likelihood of major breathing difficulties and needing a breathing tube, sudden kidney failure, blood clots, and death.^37,38

Having a substance use disorder (such as opioid, cocaine, or alcohol use disorder) may increase susceptibility to severe COVID-19. Many drugs, such as opioids, work to slow breathing and cause long-term damage to the brain, heart, and lungs, making the body weaker when COVID-19 attacks. Stimulants, such as cocaine, and vaping or smoking drugs can also cause heart and lung damage or make pre-existing lung issues worse, increasing the risk for severe COVID-19.^2,39,40

Having tuberculosis can increase the risk for severe COVID-19 given that lung function may be impaired, and the body’s resistance to viral infections like COVID-19 is low.^2,41