What is Severe COVID-19 and Who is At Risk?
What is Severe COVID-19?
COVID-19 can affect people differently. Some people experience an asymptomatic or mild infection, while others can face serious and possibly even life-threatening symptoms and complications, commonly referred to as severe COVID-19.1,2
The United States Centers for Disease Control and Prevention (CDC) defines severe outcomes of COVID-19 as hospitalization, admission to the intensive care unit (ICU), intubation or mechanical ventilation, or death.2 Severe COVID-19 as an illness is diagnosed based on clinical signs such as respiratory rate and the amount of oxygen in the blood.1
Being at high risk for severe COVID-19 is more common than many people think. In fact, approximately 75% of American adults have at least one risk factor that places them at high risk for getting very sick from COVID-19.3 And for people who are at high risk, symptoms that begin mildly can quickly become severe.4
The CDC details the factors that can increase the risk for getting severe COVID-19. They include:
- Age 50 Years or Older
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
- Chronic kidney disease
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
- Chronic liver disease
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
- Chronic lung diseases
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
- Cystic fibrosis
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
- Diabetes (Type 1 or Type 2)
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
- Heart conditions
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
- Human Immunodeficiency Virus (HIV) infection
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
- Immunocompromised condition or weakened immune system
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
- Mental health conditions
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 and being overweight
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
- Physical inactivity
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
- Sickle cell disease
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
- Smoking, current or former
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
- Solid organ or blood stem cell transplant
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
- Stroke or cerebrovascular disease
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
- Substance use disorders
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
Individuals with a known high-risk factor who test positive for COVID-19 should speak to a healthcare professional as soon as possible, even if symptoms are mild.42
In addition to certain medical conditions, being unvaccinated or not being up to date on COVID-19 vaccinations also increases the risk of severe COVID-19 outcomes.43 Rural, poor, and minority populations are also at risk of getting very sick or dying from COVID-19 because of where they live or because they can’t get healthcare.2,44,45
The list above does not include all possible conditions that may put someone at high risk of severe illness from COVID-19. Questions about a condition not included on this list should be addressed by a healthcare professional.
Pfizer’s Commitment to Preventing Progression to Severe COVID-19
From the beginning of the pandemic, we understood that fighting COVID-19 would require the power of science and unprecedented collaboration among scientists, companies, governments, and other stakeholders around the world.
Since 2020, we have been working on a multi-pronged approach focused on detection and treatment.
As the landscape continues to evolve and we continue to live alongside COVID-19, we will work to help ensure that healthcare infrastructure and supporting systems are in place to rapidly diagnose and appropriately treat patients at high risk of progressing to severe illness.
- What is considered severe COVID?
Severe outcomes of COVID-19 are defined as hospitalization, admission to the intensive care unit, intubation or mechanical ventilation, or death.2 A diagnosis of severe COVID-19 is based on specific clinical signs, including a respiratory rate over 30 breaths per minute, oxygen saturation below 94%, and lung infiltrates over 50%, as shown on radiographs.1
- What are severe COVID symptoms?
Severe COVID-19 symptoms can lead to serious outcomes from COVID-19, defined as hospitalization, admission to the intensive care unit (ICU), intubation or mechanical ventilation, or death.2 Anyone having trouble breathing should seek medical attention immediately.13 While this list does not include all possible severe COVID-19 symptoms, the CDC recommends calling for help immediately if experiencing any of the following symptoms:46
- Ongoing pain/pressure in the chest
- A sense of confusion
- Trouble staying awake or waking up
- Blue tint to the lips or face
- When do severe COVID symptoms start?
You can develop COVID-19 up to 10 days after you have been exposed.47 Symptoms may appear 2-14 days after exposure to the virus.46 Severe symptoms can arise quickly, even if initial symptoms are mild.4 To best manage COVID-19, it’s essential to be aware of risk factors, get tested at the first sign of symptom onset, and understand the importance of early, rapid treatment after diagnosis. Timely and accurate diagnosis is critical—people who do not get tested may continue their daily activities, unknowingly infecting others and increasing their likelihood of developing severe disease.2,4,42
- How long do severe COVID symptoms last?
There is no definitive amount of time that severe COVID symptoms will last. Severe COVID-19 cases can last four weeks or more and cause lasting damage. Lingering symptoms may include loss of taste and smell, cough, and shortness of breath and may last for several weeks, sometimes months, and are more common in older adults or those with pre-existing conditions.46,48
- Can mild COVID turn severe?
COVID-19 can progress to more severe disease quickly if the patient has one or more high-risk factors. It is important to get tested as quickly as possible, regardless of symptom severity.4,42
- How do you know if you have severe COVID?
Severe COVID-19 symptoms can lead to serious outcomes from COVID-19, defined as hospitalization, admission to the intensive care unit (ICU), intubation or mechanical ventilation, or death.2 Anyone having trouble breathing should seek medical attention immediately.13 While this list does not include all possible severe COVID-19 symptoms, the CDC recommends calling for help immediately if experiencing any of the following symptoms. :46
- Difficulty breathing
- Ongoing pain/pressure in the chest
- A sense of confusion
- Trouble staying awake or waking up
- Blue tint to the lips or face
- Clinical spectrum of SARS-CoV-2 infection. National Institutes of Health. https://www.covid19treatmentguidelines.nih.gov/overview/clinical-spectrum. Updated May 6, 2023. Accessed September 7, 2023.
- People with certain medical conditions. Centers for Disease Control and Prevention. https://www.cdc.gov/coronavirus/2019-ncov/need-extra-precautions/people-with-medical-conditions.html. Updated February 20, 2023. Accessed September 7, 2023.
- Ajufo E, Rao S, Navar AM, Pandey A, Ayers CR, Khera A. U.S. population at increased risk of severe illness from COVID-19. Am J Prev Cardiol 2021;6:100156. DOI: 10.1016/j.ajpc.2021.100156.
- Clinical care quick reference for COVID-19. Centers for Disease Control and Prevention. https://www.cdc.gov/coronavirus/2019-ncov/hcp/clinical-care-quick-reference.html. Updated March 16, 2022. Accessed September 7, 2023.
- Underlying medical conditions associated with higher risk for severe COVID-19: information for healthcare professionals. Centers for Disease Control and Prevention. www.cdc.gov/coronavirus/2019-ncov/hcp/clinical-care/underlyingconditions.html. Updated February 9, 2023. Accessed September 7, 2023.
- Kim, Y., et al. Characterizing cancer and COVID-19 outcomes using electronic health records. PloS ONE, 2022;17(5). Doi.org/10.1371/journal.pone.0267584.
- Venkatesulu, B.O., et al. A systematic review and meta-analysis of cancer patients affected by a novel Coronavirus. JNCI Cancer Spectrum. 2021;5(2). Doi.org/10.1093/jncics/pkaa102.
- Carter B, Ramsay EA, Short R, et al. Prognostic value of estimated glomerular filtration rate in hospitalized older patients (over 65) with COVID-19: a multicentre, European, observational cohort study. BMC Geriatr. 2022;22(1):119.
- Hemodialysis. National Institutes of Health StatPearls. Updated April 27, 2023. Accessed September 7, 2023. https://www.ncbi.nlm.nih.gov/books/NBK563296/
- SARS-CoV-2 infection and death rates among maintenance dialysis patients during delta and early omicron waves: United States, June 30, 2021-September 27, 2022. MMWR 72(32):871-876 (August 11, 2023). Accessed September 7, 2023. https://www.cdc.gov/mmwr/volumes/72/wr/mm7232a4.htm
- Nagarajan, Ramya, et al. COVID-19 severity and mortality among chronic liver disease patients: a systematic review and meta-analysis. Preventing Chronic Disease. Aug. 2022;19. Doi:10.5888/pcd19.210228.
- Controlling chronic lung diseases amid COVID-19. American Lung Association. https://www.lung.org/lung-health-diseases/lung-disease-lookup/covid-19/chronic-lung-diseases-and-covid. Updated May 1, 2023. Accessed September 7, 2023.
- COVID-19 symptoms and severity. World Health Organization. https://www.who.int/westernpacific/emergencies/covid-19/information/asymptomatic-covid-19. Updated April 18, 2023. Accessed September 7, 2023.
- Terlizzi V, Motisi MA, Pellegrino R, et al. Risk factors for severe COVID-19 in people with cystic fibrosis: A systematic review. Front Pediatr. Aug. 2022;10:958658. Doi: 10.3389/fped.2022.958658.
- COVID-19 questions and answers. Cystic Fibrosis Foundation. http://www.cff.org/managing-cf/covid-19-questions-and-answers. Accessed September 7, 2023.
- Dementia and coronavirus risk. Alzheimer’s Society. http://www.alzheimers.org.uk/get-support/coronavirus/dementia-risk. Published August 19, 2022. Accessed September 7, 2023.
- Sharma, P. (2022, July). Covid-19 and diabetes: Association intensify risk factors for morbidity and mortality. COVID-19 and diabetes: Association intensify risk factors for morbidity and mortality. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9080053/. Accessed September 7, 2023.
- COVID-19 and diabetes. International Diabetes Federation. https://www.idf.org/aboutdiabetes/what-is-diabetes/covid-19-and-diabetes/1-covid-19-and-diabetes.html. Accessed September 7, 2023.
- Landstra, C. P., & de Koning, E. J. COVID-19 and diabetes: Understanding the interrelationship and risks for a severe course. Front. Endocrinol. 2021;2. Doi.org/10.3389/fendo.2021.649525.
- Bae, S. A., Kim, S. R., Kim, M.-N., Shim, W. J., & Park, S.-M. (2021). Impact of cardiovascular disease and risk factors on fatal outcomes in patients with covid-19 according to age: A systematic review and meta-analysis. BMJ Journals, 107, 373–380. https://doi.org/10.1136/heartjnl-2020-317901
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- Guidance for COVID-19 and people with HIV. Clinical Info HIV.gov. https://clinicalinfo.hiv.gov/en/guidelines/guidance-covid-19-and-people-hiv/guidance-covid-19-and-people-hiv. Published February 22, 2022. Accessed September 7, 2023.
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