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HomeYour HealthConditionsViral IllnessesKnow Your Risk for Serious Illness from COVID-19 Know Your Risk for Serious Illness from COVID-19 

Published on Nov 15, 2023

Authored by Pfizer Medical Team

What is COVID-19?
What is COVID-19?

Coronavirus disease (COVID-19) is an infectious disease caused by the SARS-CoV-2 virus. If you are infected with the virus, you will most likely experience mild to moderate respiratory illness.


The respiratory system is composed of organs that are involved in breathing. These organs include the nose, throat, larynx, trachea (windpipe), bronchi, and lungs.


You will likely recover without requiring treatment or medication. However, some people may become seriously ill and require medical attention. You are more likely to develop serious illness from COVID-19 if you are older or you have underlying medical conditions like:

•    Cardiovascular (heart) disease

•    Diabetes

•    Chronic respiratory (lung) disease

•    Cancer

This list is not exhaustive.

COVID-19 and Pre-existing Medical Conditions

If you have one or more of the above medical conditions (risk factors) and you get COVID-19, you may be more likely to:

  • Become seriously ill

  • Be hospitalised

  • Require a machine to help you breathe

  • Need intensive care

  • Die


Did you know?About 1 in 5 (20%) people worldwide have at least one underlying condition that puts them at high-risk of becoming seriously ill from COVID-19.1
 COVID-19 and Pre-existing Medical Conditions
COVID-19 and Age
  • Your age can be a predictor of how serious your illness from COVID-19 would be.2  The older you are, the more severe your illness from COVID-19 might be.2

  • The risk of hospitalisation or death due to COVID-19 increases with age.2

    • 60x higher risk if you are 65-74 years, compared to people under 30 years.2

    • 140x higher risk if you are 75-84 years, compared to people under 30 years.2

    • 340x higher if you are 85+ years, compared to people under 30 years.2

COVID-19 and Type 1 or Type 2 Diabetes
  • If you have either Type 1 or Type 2 diabetes, you may be more likely to become seriously ill from COVID 19.

  • If you have diabetes your risk of becoming seriously ill from COVID-19 is almost 2x that of a person who does not have diabetes.3

  • If you have diabetes, you may have other conditions that may put you at high-risk of becoming seriously ill from COVID-19. Some of these conditions include:

    • High blood pressure (hypertension)

    • Cardiovascular disease

    • Chronic kidney disease

    • Obesity

  • Talk to your doctor today and discuss how you can put a COVID-19 plan in place

COVID-19 and Cancer
  • If you have cancer, your risk of becoming seriously ill from COVID-19 is higher than people who do not have cancer. Your risk of complications and death is also increased.
  • The treatments you take for your cancer, such as chemotherapy or radiation, can weaken your body’s ability to fight COVID-19.
  • If you have early-stage cancer (stage I to II cancer), your likelihood of recovering when you are diagnosed with COVID-19 is higher than if you have advanced-stage cancer (stage IV cancer).
  • If you have cancer and get COVID-19, you are more likely than a person who does not have cancer to
    • Be hospitalised
    • Need intensive care
    • Require a machine to help you breath
COVID-19 and immunocompromised conditions/weakened immune systems
  • ​​​​​​If you are taking immunosuppressive medicines, they may weaken your immune system. When your immune system is weakened, your ability to fight infections is low and increases your chance of getting very sick from COVID-19.
  • If you have or are being treated for certain medical conditions, then you may be immunocompromised (or have a weakened immune system).
  • Immunodeficiencies may be:
    • Primary immunodeficiencies that are inherited
    • Secondary immunodeficiencies that are from infections such as HIV, or from treatment with radiation or immunosuppressive medicines
Symptoms and Testing

If you have been exposed to the virus that causes COVID-19, you may develop symptoms within 5 to 6 days after exposure. Symptoms may vary from mild symptoms, such as headache, fatigue, and cough, to very severe symptoms, such as difficulty breathing, and even death. COVID-19 symptoms may be similar to those you may have due to other infections, such as the flu.

If you have flu-like symptoms, it may be COVID-19 and not the flu. Get tested for COVID-19 as soon as possible if you develop symptoms. Find out more about other viral illnesses and how best to treat them by visiting A Guide to Common Cold & Winter Viruses: What It Is, Symptoms & Treatments

Symptoms can include, but are not limited to:

  • Sore throat

  • Loss of smell or taste

  • Shortness of breath or difficulty breathing

  • Fatigue

  • Fever or chills

  • Congestion or runny nose

  • Diarrhoea

  • Nausea or vomiting

  • Muscle or body aches

  • Cough

  • Headache

What to do if you test positive? 

Although this article is not intended to provide specific advice to any individual, here are some important things to be aware of:

  • If your test result is positive for COVID-19, do not delay. Speak to or notify your healthcare provider as soon as possible, even if your symptoms are mild.
  • If you have difficulty breathing, seek immediate medical attention.
  • Your healthcare provider can tell you about treatment options for COVID-19 and if one is appropriate for you. Your healthcare provider can also tell you about appropriate self-care.
  • These treatments must be started within days (generally 5-7 days) after you start developing symptoms. This is why it is so important to contact your healthcare provider as soon as possible.

Click here to check if you're eligible for COVID-19 antiviral medicines

If you think you have been exposed to COVID-19 or have developed symptoms, get tested for COVID-19 as soon as possible.




  1. Clark, A., Jit, M., Warren-Gash, C., Guthrie, B., Wang, H. H. X., Mercer, S. W., Sanderson, C., McKee, M., Troeger, C., Ong, K. I., Checchi, F., Perel, P., Joseph, S., Gibbs, H. P., Banerjee, A., & Eggo, R. M. (2020). How many are at increased risk of severe COVID-19 disease? rapid global, regional and national estimates for 2020. The Lancet Global Health, 1003–1017. 

  2. Underlying medical conditions associated with higher risk for severe COVID-19: Information for Healthcare professionals. Centers for Disease Control and Prevention. (2022, February 15). Retrieved May 20, 2022, from

  3. 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.

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