Why it’s so difficult to assess pandemic risks right now

California in recent weeks has inched away from its strictest pandemic policies, lifting its indoor mask mandates and some vaccination requirements. The state last month released a long-term plan for living with the coronavirus, instead of treating it as an emergency.

But at the same time, thousands of Californians continue to contract COVID-19 daily, while concerns grow that a new wave could be coming to the United States.

If it seems particularly difficult to assess COVID dangers right now, that’s because it is.

California has entered a new phase of the pandemic, in which its residents have more responsibility for deciding on safety precautions than ever before. And unfortunately, humans are not very good at understanding risk.

Our perceptions are influenced by news coverage, policies, our personal experiences, the behaviors of people around us and so much more. Sometimes, or perhaps even often, our judgment is wildly off.

Take this Stanford study. In May 2020, the average American believed the risk of catching the coronavirus while grocery shopping was 40 percent, and 62 percent when on public transportation, the researchers found.

At that time, the fraction of Americans who had ever tested positive for the coronavirus was less than 1%.

“We found that people drastically overestimated the risk,” said Maria Polyakova, one of the study’s authors and an assistant professor of health policy at Stanford. “People are really not good at understanding small risks.”

Add to that the fact that the risk of severe COVID varies from person to person, and that the prevalence of the virus differs across communities and changes constantly, and the calculation becomes extremely complicated. There’s no universal answer.

Anne Rimoin, an epidemiologist at UCLA, said she worried that there was another, new factor at play too: pandemic fatigue. She has been tracking a highly transmissible coronavirus subvariant that’s fueling a surge in Europe and becoming increasingly common here.

“Everybody is ready for COVID to be over,” Rimoin told me. “It’s like a kid in the back seat of a car saying, ‘Are we there yet? Are we there yet?’ We’re not there yet.”

But it can be difficult to translate those small risks into behavioral changes, experts say.

The decisions we make — Will I fly to that wedding? Should I eat at an indoor restaurant? — tend to be yes-or-no choices, not behaviors we can modify by, say, 10%, said Craig McKenzie, a psychology professor at UC San Diego.

So we’re all searching for a threshold at which we can stop adjusting our behaviors to avoid COVID, he said. And some people may already feel they have reached that place.

“Flu is a risk, flying is a risk, driving is a risk — we can’t attend to all of them,” he told me. “At some point I have to act as if this doesn’t matter because, if the risk is one in a million, should I change my behavior?”

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