About the Fight COVID MKE COVID-19 Individual Risk Estimator

COVID-19 is a disease that is caused by a coronavirus. This risk assessment tool gives estimates of how much COVID has affected people like you, based on the information you provide. The tool is based on data through December 31, 2021.

How to Use the Tool: When you put your information in the Basic Data and Health Data boxes on the left of the tool, the pictures on the right change to show how COVID has affected people like you. You can also put in information about another person to see their risk. The information you enter is confidential and is not stored.

COVID Risk Estimator Guide

We provide three sets of results, with answers to different questions. 

COVID Burden Box: This box shows our best estimates, using the information you provided, for:

  • Your life expectancy – how long someone like you will live, on average, with no COVID
  • The approximate percentage of people in your state who have been infected with COVID. This percentage includes many people who had no or mild symptoms and never knew they had COVID.
  • The proportion of people like you who have died from COVID
  • How much COVID has reduced life expectancy for people like you.

Estimates of life expectancy are for large groups of people. They are NOT predictions for individual people.

Graphs of your risk TODAY: Many people are still dying of COVID. The top bar chart shows your expected loss of life expectancy TODAY, measured in days. The yellow bars show your risk if you are unvaccinated; green bars show your risk if you received two doses of the Pfizer or Moderna vaccine more than 6 months ago; blue bars show your risk if you were vaccinated more recently, or else either received a booster dose. The bottom chart shows the risk of death. These risks depend on your risk of infection.

The Johnson & Johnson vaccine provides less protection than Pfizer or Moderna, but protection improves if you receive a booster shot using another vaccine.

Comparing COVID to Other Risks: This box lets you compare COVID risk to other common risks. It shows, for people like you, how life expectancy is affected by car accidents, cancer, and flu and pneumonia (from causes other than COVID). This box compares the average days of life lost due from COVID through December 2021, for people like you, to one-year estimates of lost life expectancy loss from the other causes.

How you can reduce your risk:
Vaccination reduces your risk of becoming infected and greatly reduces your risk of becoming seriously ill from COVID. Vaccines also help keep you from infecting people around you. Serious side effects from vaccination are very rare compared to COVID. The yellow bars show the chance someone like you will die from COVID. For vaccines, the risk of a serious side effect is less than 1 out of 100,000 and almost all people with serious vaccine side effects recover.

Vaccine boosters: Vaccine protection wears off over time. But you can get another shot of the vaccine, called a booster, which restores your protection. The CDC recommends a booster for the Pfizer and Moderna vaccines after 6 months, and for the Johnson & Johnson vaccine after 2 months.

What if you were already infected. If you were already infected, you can still get infected again. Vaccination will still greatly reduce your risk of becoming severely ill or dying. The antibodies from your prior infection may provide additional protection, but this protection can also wear off over time.

The risks shown in the graph above are based on the best data available to us. We estimate the following reductions in risk, for persons who were vaccinated or vaccinated and boosted. The graph shows risks relative to the risk, shown as equal to 1.00, for persons who are neither vaccinated nor previously infected.

The table provides our best current estimates of risk reduction for Omicron variant, which is currently the dominant COVID variant. For many people, the Omicron variant is less severe than prior variants, but it remains deadly, especially for the elderly. Vaccines still provide important protection, but less than for prior variants. 

   Not previously infected or vaccinated (two doses) Previously infected or vaccinated more than 6 months ago  Vaccinated within 6 months (or vaccinated plus booster)
Risk of symptomatic infection  1.00 0.750 0.50 
Risk of hospitalization  1.00  0.70 0.25 
 Risk of death  1.00  0.30 0.10 

Some more details about the risk assessment tool:

For advice about your personal situation, please speak with your doctor or other healthcare professional. 

  1. Virus mutations. Coronavirus mutations can increase the risk of infection and reduce the degree of protection you receive from prior infection or vaccination. The Omicron variant is highly infectious and often infects people who were vaccinated or previously infected. However, it appears on average to cause less severe illness than earlier variants, especially for persons who are vaccinated or previously infected.

  2. Actual versus confirmed infections. Many more people were infected with COVID than the number of confirmed infections. We assume that for every infection that is confirmed by a test reported to the Centers for Disease Prevention and Control (CDC), there were three actual infections. This is because many people don’t get tested, either because they have no or only mild symptoms or because they are pretty sure they know they have COVID. Also, many at-home tests are not reported to the CDC. We believe that this three-to-one ratio is reasonable, but the actual ratio is unknown and varies depending on where you live.

  3. Risk of hospitalization. We think your risk of hospitalization is about 10 times your risk of dying of COVID, and perhaps more. But data are limited, so this is an estimate. There are not enough data to say how this risk varies with age or other personal factors, vaccination status, or prior infection.

  4. Risk after being vaccinated: The tool shows the reduced risk if you are vaccinated, starting 14 days after the second dose, for the Pfizer or Moderna vaccines. This is when these vaccines should be fully effective. The Johnson and Johnson vaccine is less effective in preventing severe illness.

  5. Risk if you are vaccinated and were already infected: If you were both already infected and vaccinated, your risk of being infected again, or of having a serious infection, may be lower than from vaccination alone. The risk reduction reported in this risk tool does not take into account the additional reduction from being both vaccinated and already infected.

  6. Vaccine safety. All available evidence is that the Pfizer and Moderna vaccines are highly safe and greatly reduce both your risk, and the risk that you will infect other people. Most side effects are minor. There is a small risk, for around 1 in 100,000 persons, of a severe allergic reaction to the shot. This is why people who are vaccinated are asked to wait for 15-30 minutes before leaving the vaccination site, so that any allergic reaction can be treated. There is also a small risk of heart muscle inflammation, seen mostly in young men, which is usually mild and goes away within a few weeks. The risk of heart muscle inflammation (called myocarditis) is greater from COVID infection than from the vaccines.

    For the Johnson & Johnson vaccine, there is a very small risk of developing potentially serious blood clots during the several weeks following vaccination. This risk is principally for women age 18-49, and for them is under 1 in 100,000 persons. There is also a similar risk, principally for older men, of developing a nerve disorder called Guillain-Barre syndrome, which can cause temporary paralysis. These risks, plus lower efficacy for the Johnson & Johnson vaccine, have led the CDC to recommend the Pfizer and Moderna vaccines.

  7. Long-term symptoms. Some people can have long-term symptoms due to a COVID infection, including fatigue, cough, loss of taste or smell, and other symptoms. If you think you may have long-term COVID symptoms, please speak with a doctor.

  8. Effect of other diseases on COVID risk: Chronic diseases affect both your risk from COVID and your life expectancy without COVID. We do not know enough about how other diseases affect COVID risk to take them into account in predicting your COVID risk.

For details on how we estimate life expectancy and COVID risk, see A COVID-19 Risk Calculator: Mortality Rates and Loss of Life Expectancy, at

About the Fight COVID MKE Project

This risk assessment tool was created by the Fight COVID MKE research team. MKE are initials for Milwaukee County, Wisconsin. However, the tool provides nationwide answers to COVID risk questions, which vary depending on where you live.

Lead researchers: The researchers who developed the risk assessment tool include, in alphabetical order, Vladimir Atanasov (William & Mary), Bernard Black (Northwestern University), Eric Luo (George Washington University), John Meurer (Medical College of Wisconsin), Paula Natalia Barreto Parra (Northwestern), Jeffrey Whittle (Medical College of Wisconsin), and Ruohao Zhang (Northwestern University).

Our research is supported by a grant from the National Institutes of Health.

A detailed discussion of our data sources and methods is available at  

Questions and suggestions for improvement: Please contact Professor Bernard Black at


The information, including but not limited to, text, graphics, images and other material contained on this website are for informational purposes only. No material on this site is intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of your physician or other qualified health care provider with any questions you may have regarding a medical condition or treatment and before undertaking a new health care regimen, and never disregard professional medical advice or delay in seeking it because of something you have read on this website.