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Last updated September 9, 2021. 4 minute read

Who’s most at risk for severe COVID-19 symptoms?

Anyone can develop severe symptoms. Just because you are young and healthy does not mean you are entirely protected from the disease. However, advanced age and certain underlying medical conditions do put you at an increased risk.

Dr Mike Bohl Md Mph Written by Mike Bohl, MD, MPH
Reviewed by Rachel Kwon, MD

Developed in partnership with

Chances are, you’ve had a cold (or several) in your lifetime. You may have even experienced a more intense respiratory infection at some point, like influenza (“the flu”) or pneumonia. If you have, you’ll know that respiratory infections can cause a whole host of symptoms, including fever, chest pain, congestion, cough, sneezing, shortness of breath, sore throat, body aches, fatigue, and more. But you’ll also know that you probably don’t experience all of these symptoms every time you get sick, and the symptoms can also range from mild to severe. For example, sometimes, the common cold is just an annoyance, but other times, they can be so bad they keep you in bed (or may even require hospitalization and breathing assistance).

Part of the reason for this is that not all respiratory infections are the same. They can be caused by different organisms (such as different types of bacteria, viruses, or fungi), and they can infect different parts of your respiratory system (such as the inside of your nose or lungs).

But the other part of the reason for this is that not everybody experiences the same disease in the same way. Certain factors, such as your age or whether you have other medical conditions, can put you at a higher risk of developing serious disease. And this is especially important to keep in mind during the ongoing coronavirus disease 2019 (COVID-19) pandemic.

COVID-19 is caused by a virus known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). SARS-CoV-2 is part of a family of viruses known as coronaviruses. Some coronaviruses cause respiratory illnesses in humans. These include the common cold, severe acute respiratory syndrome (SARS), and Middle East respiratory syndrome (MERS). Like these other diseases, COVID-19 is a respiratory illness.

Most people with COVID-19 experience mild symptoms. In fact, one study reported that 80.9% of individuals with COVID-19 symptoms only experience mild disease (NCIP Team, 2020). Additionally, one study found that at least one-third of people who were infected may be entirely asymptomatic, meaning they don’t experience any symptoms at all (and may not even know they have the virus)(Oran, 2021).

But there is another end of the spectrum. A study of over 44,000 people with confirmed COVID-19 found that 14% developed severe disease (meeting certain breathing conditions), 5% developed critical disease (having respiratory failure, organ failure, or shock), and 2.3% died (Wu, 2020). While the exact fatality rate of COVID-19 differs depending on a variety of factors, the point is: SARS-CoV-2 can cause such a range of disease that some are asymptomatic while others are dying.

What are the symptoms of COVID-19?

According to the Centers for Disease Control and Prevention (CDC), symptoms start showing up between 2–14 days after exposure (CDC, 2021-b). One study found that the average time before symptoms show up is 5.1 days, with 97.5% of infected people experiencing symptoms within 11.5 days (Lauer, 2020).

The most common symptoms of COVID-19 include (CDC, 2021-b):

  • Cough
  • Fever
  • Muscle pain
  • Headache
  • Shortness of breath
  • Sore throat
  • Diarrhea
  • Nausea/vomiting
  • Loss of smell
  • Loss of taste
  • Abdominal pain
  • Runny nose

Who is at greater risk for severe illness with COVID-19?

It is possible for everyone to develop severe symptoms. Just because you are young and healthy does not mean you are entirely protected from the disease. However, advanced age and certain medical comorbidities do put you at an increased risk.

Having any of the following underlying medical conditions is associated with developing severe disease from COVID-19 (CDC, 2021-a):

  • Chronic kidney disease
  • Chronic obstructive pulmonary disease (COPD)
  • Cancer
  • Weakened immune system
  • Obesity
  • Heart disease
  • Sickle cell disease
  • Type 2 diabetes

The CDC also offers more information for a few specific groups:

What about age?

You have likely heard that older adults are at increased risk of having severe symptoms and dying from COVID-19, and this is true. Multiple studies have shown that older age is associated with poorer outcomes. One study found that 31% of cases, 45% of hospitalizations, 53% of intensive care unit (ICU) admissions, and 80% of deaths associated with COVID-19 were in individuals aged 65 and over. It also found that the highest percentage of severe outcomes was in individuals aged 85 and over (Bialek, 2020).

To reiterate, 8 out of 10 deaths in the United States from COVID-19 have been in individuals aged 65 and over. The CDC offers specific information for adults over 65, which can be found here:

So, what should you do?

No matter who you are and what your medical conditions are, there are several easy steps you can take to help prevent getting infected with SARS-CoV-2. If possible, avoid contact with people who are sick. Contact your local pharmacy to find out where you can get vaccinated. Vaccination is a great way to protect not only yourself but also the people around you. If you are going to be around people who are not vaccinated, it’s best to make sure everyone has been tested for COVID and continues wearing face masks. Wash your hands frequently—especially before eating and touching your face. And if you do think you are sick and at risk of getting severe symptoms, do not hesitate to seek medical care.


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  2. Centers for Disease Control and Prevention. (2021-b, February 22). Symptoms of COVID-19. Retrieved September 9, 2021, from
  3. Lauer, S. A., Grantz, K. H., Bi, Q., Jones, F. K., Zheng, Q., Meredith, H. R., … Lessler, J. (2020). The Incubation Period of Coronavirus Disease 2019 (COVID-19) From Publicly Reported Confirmed Cases: Estimation and Application. Annals of Internal Medicine. doi: 10.7326/m20-0504,
  4. Novel Coronavirus Pneumonia Emergency Response Epidemiology Team. (2020). [The Epidemiological Characteristics of an Outbreak of 2019 Novel Coronavirus Diseases (COVID-19) in China]. Zhonghua Liu Xing Bing Xue Za Zhi. 41(2), 145–151. doi: 10.3760/cma.j.issn.0254-6450.2020.02.003,
  5. Oran, D. P., & Topol, E. J. (2021). The Proportion of SARS-CoV-2 Infections That Are Asymptomatic : A Systematic Review. Annals of internal medicine174(5), 655–662. doi:10.7326/M20-6976. Retrieved from
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  7. Wu, Z., & Mcgoogan, J. M. (2020). Characteristics of and Important Lessons From the Coronavirus Disease 2019 (COVID-19) Outbreak in China. JAMA, 323(13), 1239. doi: 10.1001/jama.2020.2648,