“How risky is it to be indoors with our 10-year-old granddaughter without masks?” We have plans to have tea together for our birthday. Are we safe? “

This question from a woman named Debbie from California is just one of hundreds I have received from concerned people who are worried about COVID-19. I am an epidemiologist and one of the women in the back Dear Pandemica scientific communication project that provides practical pandemic advice on social media since the beginning of the pandemic.

How risky is the swimming team? How risky is it to go to an orthodontist for an hour? How risky is it to go to the grocery store with a mask if no one else wears one and my father has received an organ transplant? How risky is it to have a wedding with 200 people, indoors, and the reception room has a vaulted ceiling? And on and on.

These are the questions difficult to answerand even when we try, the answers are unsatisfactory.

So in early April 2022, when Anthony Fauci, the president’s chief medical adviser, told Americans that from now on, each of us will have to make your own personal risk assessmentI put my head on my desk.

An individual risk assessment is not a reasonable request, even for someone who does a risk assessment to make a living, let alone the rest of us. It is impossible to assess our own risk for a situation, and the impossibility of the task can make us give up completely. So instead of doing that, I suggest you focus on reducing the risk. Reforming in this way brings us back to the realm of what we can control and to proven and truly evidence-based strategies: wearing masks, vaccinating and reinforcing, avoiding indoor crowds, and improving ventilation.

A cascade of unknowable variables

In my experience, scientists and epidemiologists use the word “risk” to mean different things. For most people, risk means quality – something like danger or vulnerability.

However, when epidemiologists and other scientists use the word risk, we are talking about a mathematical problem. Risk is the probability of a specific outcome, in a certain population at a certain time. To give a simple example, the odds that a coin toss will be heads are 1 in 2.

As public health researchers, we often offer risk information in this format: The likelihood of an unvaccinated person dying from COVID-19 if caught is 1 in 200. As much as 1 out of 8 people with COVID-19 there will be symptoms that last for weeks or months after recovery.

In order to deal with your personal risk assessment, as Fauci casually suggested, you must first decide what outcome you are talking about. People are often not very specific when looking at risk in a qualitative sense; they tend to combine many different risks. But risk is not a general concept. There is always a risk of a specific result.

Let’s think about Debbie. First, there is a risk that she will be exposed to COVID-19 during tea; it depends on her granddaughter. Where does she live? How many children in her school have COVID-19 this week? Will he take a quick test before he comes? All of these factors affect my granddaughter’s risk of exposing Debbie to COVID-19, but I don’t know any of them, and probably Debbie. Given the lack of systematic testing, I have no idea how many people in my own community currently have COVID-19. At this point, our best guess at community prices is literally in the toiletsewer monitoring for coronavirus.

Assuming that Debbie’s granddaughter does have COVID-19 on the particular day, I can begin to think about Debbie’s downstream risks: whether she will receive COVID-19 from her granddaughter; the chances of her being hospitalized and dying; and the probability that she will have long COVID. I can also consider the risk of Debbie catching COVID-19 and then passing it on to others, perpetuating an epidemic. If she gets sick, the whole hierarchy of risks comes into play for everyone Debbie sees after being infected.

Finally, there are competitive risks. If Debbie decides to miss the party, there may be risks to her own or her granddaughter’s mental health or relationship. Many missed celebrations in many families may have a negative impact on the economy. People can lose business; they may lose their jobs.

Each of these probabilities is influenced by a cascade of volatile conditions. Some of the factors that shape the risks are under your control. For example, I decided to get vaccinated and get stronger. Therefore, I am less likely to end up in the hospital and die if I get COVID-19. But some risks are out of your control – age, other health conditions, gender, race and behavior of the people around you. And many, many of the risk factors are simply unknown. We will never be able to accurately estimate the entire variable risk landscape for a particular situation and come up with a number.

Take responsibility for what you can

There will never be a situation where I can tell Debbie: The risk is 1 in 20. And even if I could, I’m not sure it would be helpful. Most people find it very difficult to understand the probabilities they face every day, such as the chance to rain.

The statistical risk of a specific result does not answer Debbie’s main question: Are we safe?

Nothing is completely safe. If you want my professional opinion on whether it is safe to walk on the sidewalk, I will have to say no. Bad things happen. I know someone who tore a tendon in his arm while putting a fitted sheet on a bed last week.

It is much more practical to ask: What can I do to reduce the risk?

Focusing on actions that reduce risk frees us from obsessing over unanswered questions with useless answers so that we can focus on what is under our control. I’ll never know exactly how risky Debbie’s tea is, but I will you know how to reduce the risks.

I suspect that the question people are really asking themselves is: How can I manage risk? I like this question more because there is an answer: You have to do what you can. If it is wise to wear a mask, wear it. Yes, even if it is not mandatory. If it is reasonable to do antigen test at home before you see your vulnerable grandparents, do this. Get vaccinated and get stronger. Tell your friends and family what he did and why. Choose outdoor gatherings. Open a window.

The ongoing assessment and reassessment of risks is given the fatigue of many people in making decisions. I feel it too. But you don’t have to calibrate the risks for everything, every day, for every option, because the risk reduction strategies remain the same. Reducing the risk – even if only slightly – is better than doing nothing.