Coronavirus Risk Calculators: What You Need to Know
A screenshot of one coronavirus risk calculator.
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.
The Cellular Secrets of “Young Blood” Are Starting to Be Unlocked
Fabrisia Ambrosio (center) surrounded by her lab staff.
The quest for an elixir to restore youthful health and vigor is common to most cultures and has prompted much scientific research. About a decade ago, Stanford scientists stitched together the blood circulatory systems of old and young mice in a practice called parabiosis. It seemed to rejuvenate the aged animals and spawned vampirish urban legends of Hollywood luminaries and tech billionaires paying big bucks for healthy young blood to put into their own aging arteries in the hope of reversing or at least forestalling the aging process.
It was “kind of creepy” and also inspiring to Fabrisia Ambrosio, then thousands of miles away and near the start of her own research career into the processes of aging. Her lab is at the University of Pittsburgh but on this cold January morning I am speaking with her via Zoom as she visits with family near her native Sao Paulo, Brazil. A gleaming white high rise condo and a lush tropical jungle split the view behind her, and the summer beach is just a few blocks away.
Ambrosio possesses the joy of a kid on Christmas morning who can't wait to see what’s inside the wrapping. “I’ve always had a love for research, my father was a physicist," she says, but interest in the human body pulled her toward biology as her education progressed in the U.S. and Canada.
Back in Pittsburgh, her lab first extended the work of others in aging by using the simpler process of injecting young blood into the tail vein of old mice and found that the skeletal muscles of the animals “displayed an enhanced capacity to regenerate.” But what was causing this improvement?
When Ambrosio injected old mice with young blood depleted of EVs, the regenerative effect practically disappeared.
The next step was to remove the extracellular vesicles (EVs) from blood. EVs are small particles of cells composed of a membrane and often a cargo inside that lipid envelope. Initially many scientists thought that EVs were simply taking out the garbage that cells no longer needed, but they would learn that one cell's trash could be another cell's treasure.
Metabolites, mRNA, and myriad other signaling molecules inside the EV can function as a complex network by which cells communicate with others both near and far. These cargoes can up and down-regulate gene expression, affecting cell activity and potentially the entire body. EVs are present in humans, the bacteria that live in and on us, even in plants; they likely communicate across all forms of life.
Being inside the EV membrane protects cargo from enzymes and other factors in the blood that can degrade it, says Kenneth Witwer, a researcher at Johns Hopkins University and program chair of the International Society for Extracellular Vesicles. The receptors on the surface of the EV provide clues to the type of cell from which it originated and the cell receptors to which it might later bind and affect.
When Ambrosio injected old mice with young blood depleted of EVs, the regenerative effect practically disappeared; purified EVs alone were enough to do the job. The team also looked at muscle cell gene expression after injections of saline, young blood, and EV-depleted young blood and found significant differences. She believes this means that the major effect of enhanced regenerative capacity was coming from the EVs, though free floating proteins within the blood may also contribute something to the effect.
One such protein, called klotho, is of great interest to researchers studying aging. The name was borrowed from the Fates of Greek mythology, which consists of three sisters; Klotho spins the thread of life that her sisters measure and cut. Ambrosio had earlier shown that supplementing klotho could enhance regenerative capacity in old animals. But as with most proteins, klotho is fragile, rapidly degrading in body fluids, or when frozen and thawed. She suspected that klotho could survive better as cargo enclosed within the membrane of an EV and shielded from degradation.
So she went looking for klotho inside the EVs they had isolated. Advanced imaging technology revealed that young EVs contained abundant levels of klotho mRNAs, but the number of those proteins was much lower in EVs from old mice. Ambrosio wrote in her most recent paper, published in December in Nature Aging. She also found that the stressors associated with aging reduced the communications capacity of EVs in muscle tissue and that could be only partially restored with young blood.
Researchers still don't understand how klotho functions at the cellular level, but they may not need to know that. Perhaps learning how to increase its production, or using synthetic biology to generate more copies of klotho mRNA, or adding cell receptors to better direct EVs to specific aging tissue will be sufficient to reap the anti-aging benefits.
“Very, very preliminary data from our lab has demonstrated that exercise may be altering klotho transcripts within aged extracellular vesicles" for the better Ambrosio teases. But we already know that exercise is good for us; understanding the cellular mechanism behind that isn't likely to provide additional motivation to get up off the couch. Many of us want a prescription, a pill that is easy to take, to slow our aging.
Ambrosio hopes that others will build upon the basic research from her lab, and that pharmaceutical companies will be able to translate and develop it into products that can pass through FDA review and help ameliorate the diseases of aging.
Podcast: Should Scientific Controversies Be Silenced?
The recent Joe Rogan/Spotify controversy prompts the consideration of tough questions about expertise, trust, gatekeepers, and dissent.
The "Making Sense of Science" podcast features interviews with leading medical and scientific experts about the latest developments and the big ethical and societal questions they raise. This monthly podcast is hosted by journalist Kira Peikoff, founding editor of the award-winning science outlet Leaps.org.
The recent Joe Rogan/Spotify backlash over the misinformation presented in his recent episode on the Covid-19 vaccines raises some difficult and important bioethical questions for society: How can people know which experts to trust? What should big tech gatekeepers do about false claims promoted on their platforms? How should the scientific establishment respond to heterodox viewpoints from experts who disagree with the consensus? When is silencing of dissent merited, and when is it problematic? Journalist Kira Peikoff asks infectious disease physician and pandemic scholar Dr. Amesh Adalja to weigh in.
Dr. Amesh Adalja, Senior Scholar, Johns Hopkins Center for Health Security and an infectious disease physician
Listen to the Episode
Kira Peikoff was the editor-in-chief of Leaps.org from 2017 to 2021. As a journalist, her work has appeared in The New York Times, Newsweek, Nautilus, Popular Mechanics, The New York Academy of Sciences, and other outlets. She is also the author of four suspense novels that explore controversial issues arising from scientific innovation: Living Proof, No Time to Die, Die Again Tomorrow, and Mother Knows Best. Peikoff holds a B.A. in Journalism from New York University and an M.S. in Bioethics from Columbia University. She lives in New Jersey with her husband and two young sons. Follow her on Twitter @KiraPeikoff.