Coronavirus Risk Calculators: What You Need to Know

Coronavirus Risk Calculators: What You Need to Know

A screenshot of one coronavirus risk calculator.

(https://www.solenya.org/coronavirus)

People in my family seem to develop every ailment in the world, including feline distemper and Dutch elm disease, so I naturally put fingers to keyboard when I discovered that COVID-19 risk calculators now exist.


"It's best to look at your risk band. This will give you a more useful insight into your personal risk."

But the results – based on my answers to questions -- are bewildering.

A British risk calculator developed by the Nexoid software company declared I have a 5 percent, or 1 in 20, chance of developing COVID-19 and less than 1 percent risk of dying if I get it. Um, great, I think? Meanwhile, 19 and Me, a risk calculator created by data scientists, says my risk of infection is 0.01 percent per week, or 1 in 10,000, and it gave me a risk score of 44 out of 100.

Confused? Join the club. But it's actually possible to interpret numbers like these and put them to use. Here are five tips about using coronavirus risk calculators:

1. Make Sure the Calculator Is Designed For You

Not every COVID-19 risk calculator is designed to be used by the general public. Cleveland Clinic's risk calculator, for example, is only a tool for medical professionals, not sick people or the "worried well," said Dr. Lara Jehi, Cleveland Clinic's chief research information officer.

Unfortunately, the risk calculator's web page fails to explicitly identify its target audience. But there are hints that it's not for lay people such as its references to "platelets" and "chlorides."

The 19 and Me or the Nexoid risk calculators, in contrast, are both designed for use by everyone, as is a risk calculator developed by Emory University.

2. Take a Look at the Calculator's Privacy Policy

COVID-19 risk calculators ask for a lot of personal information. The Nexoid calculator, for example, wanted to know my age, weight, drug and alcohol history, pre-existing conditions, blood type and more. It even asked me about the prescription drugs I take.

It's wise to check the privacy policy and be cautious about providing an email address or other personal information. Nexoid's policy says it provides the information it gathers to researchers but it doesn't release IP addresses, which can reveal your location in certain circumstances.

John-Arne Skolbekken, a professor and risk specialist at Norwegian University of Science and Technology, entered his own data in the Nexoid calculator after being contacted by LeapsMag for comment. He noted that the calculator, among other things, asks for information about use of recreational drugs that could be illegal in some places. "I have given away some of my personal data to a company that I can hope will not misuse them," he said. "Let's hope they are trustworthy."

The 19 and Me calculator, by contrast, doesn't gather any data from users, said Cindy Hu, data scientist at Mathematica, which created it. "As soon as the window is closed, that data is gone and not captured."

The Emory University risk calculator, meanwhile, has a long privacy policy that states "the information we collect during your assessment will not be correlated with contact information if you provide it." However, it says personal information can be shared with third parties.

3. Keep an Eye on Time Horizons

Let's say a risk calculator says you have a 1 percent risk of infection. That's fairly low if we're talking about this year as a whole, but it's quite worrisome if the risk percentage refers to today and jumps by 1 percent each day going forward. That's why it's helpful to know exactly what the numbers mean in terms of time.

Unfortunately, this information isn't always readily available. You may have to dig around for it or contact a risk calculator's developers for more information. The 19 and Me calculator's risk percentages refer to this current week based on your behavior this week, Hu said. The Nexoid calculator, by contrast, has an "infinite timeline" that assumes no vaccine is developed, said Jonathon Grantham, the company's managing director. But your results will vary over time since the calculator's developers adjust it to reflect new data.

When you use a risk calculator, focus on this question: "How does your risk compare to the risk of an 'average' person?"

4. Focus on the Big Picture

The Nexoid calculator gave me numbers of 5 percent (getting COVID-19) and 99.309 percent (surviving it). It even provided betting odds for gambling types: The odds are in favor of me not getting infected (19-to-1) and not dying if I get infected (144-to-1).

However, Grantham told me that these numbers "are not the whole story." Instead, he said, "it's best to look at your risk band. This will give you a more useful insight into your personal risk." Risk bands refer to a segmentation of people into five categories, from lowest to highest risk, according to how a person's result sits relative to the whole dataset.

The Nexoid calculator says I'm in the "lowest risk band" for getting COVID-19, and a "high risk band" for dying of it if I get it. That suggests I'd better stay in the lowest-risk category because my pre-existing risk factors could spell trouble for my survival if I get infected.

Michael J. Pencina, a professor and biostatistician at Duke University School of Medicine, agreed that focusing on your general risk level is better than focusing on numbers. When you use a risk calculator, he said, focus on this question: "How does your risk compare to the risk of an 'average' person?"

The 19 and Me calculator, meanwhile, put my risk at 44 out of 100. Hu said that a score of 50 represents the typical person's risk of developing serious consequences from another disease – the flu.

5. Remember to Take Action

Hu, who helped develop the 19 and Me risk calculator, said it's best to use it to "understand the relative impact of different behaviors." As she noted, the calculator is designed to allow users to plug in different answers about their behavior and immediately see how their risk levels change.

This information can help us figure out if we should change the way we approach the world by, say, washing our hands more or avoiding more personal encounters.

"Estimation of risk is only one part of prevention," Pencina said. "The other is risk factors and our ability to reduce them." In other words, odds, percentages and risk bands can be revealing, but it's what we do to change them that matters.

Randy Dotinga
Randy Dotinga is former president of the American Society of Journalists and Authors, a non-profit association of freelance writers and non-fiction authors. He has been a freelance writer since 1999 and specializes in health/medicine, politics, books, and the odd and unusual. You can follow him at @rdotinga.
New tech aims to make the ocean healthier for marine life

Overabundance of dissolved carbon dioxide poses a threat to marine life. A new system detects elevated levels of the greenhouse gases and mitigates them on the spot.

Adobe Stock

A defunct drydock basin arched by a rusting 19th century steel bridge seems an incongruous place to conduct state-of-the-art climate science. But this placid and protected sliver of water connecting Brooklyn’s Navy Yard to the East River was just right for Garrett Boudinot to float a small dock topped with water carbon-sensing gear. And while his system right now looks like a trio of plastic boxes wired up together, it aims to mediate the growing ocean acidification problem, caused by overabundance of dissolved carbon dioxide.

Boudinot, a biogeochemist and founder of a carbon-management startup called Vycarb, is honing his method for measuring CO2 levels in water, as well as (at least temporarily) correcting their negative effects. It’s a challenge that’s been occupying numerous climate scientists as the ocean heats up, and as states like New York recognize that reducing emissions won’t be enough to reach their climate goals; they’ll have to figure out how to remove carbon, too.

Keep Reading Keep Reading
Lela Nargi
Lela Nargi is a Brooklyn, NY-based veteran freelance journalist covering food and agriculture system, social justice issues, science & the environment, and the places where those topics intersect for The New York Times, The Guardian, the Food and Environment Reporting Network (FERN), Eater, Modern Farmer, USA Today, and other outlets. Find her at lelanargi.com.
Advocates fight back against harmful chemicals in kids' makeup and hair products

Many children use makeup and body products such as glitter, face paint and lip gloss. Scientists are pointing to the harmful chemicals in some of these products, and advocates are looking to outlaw them.

Adobe Stock

When Erika Schreder’s 14-year-old daughter, who is Black, had her curly hair braided at a Seattle-area salon two or three times recently, the hairdresser applied a styling gel to seal the tresses in place.

Schreder and her daughter had been trying to avoid harmful chemicals, so they were shocked to later learn that this particular gel had the highest level of formaldehyde of any product tested by the Washington State Departments of Ecology and Health. In January 2023, the agencies released a report that uncovered high levels of formaldehyde in certain hair products, creams and lotions marketed to or used by people of color. When Schreder saw the report, she mentioned it to her daughter, who told her the name of the gel smoothed on her hair.

“It was really upsetting,” said Schreder, science director at Toxic-Free Future, a Seattle-based nonprofit environmental health research and advocacy organization. “Learning that this product used on my daughter’s hair contained cancer-causing formaldehyde made me even more committed to advocating for our state to ban toxic ingredients in cosmetics and personal care products.”

Keep Reading Keep Reading
Susan Kreimer
Susan Kreimer is a New York-based freelance journalist who has followed the landscape of health care since the late 1990s, initially as a staff reporter for major daily newspapers. She writes about breakthrough studies, personal health, and the business of clinical practice. Raised in the Chicago area, she holds a B.A. in Journalism/Mass Communication and French, with minors in German and Russian, from the University of Iowa and an M.S. from the Columbia University Graduate School of Journalism.