Unless you learnt Latin and Greek or went to medical school, words such as "sequelae", "encephalopathy" or "anosmia" probably mean nothing to you. That may be about to change, at least if you try to keep up with the literature about Covid-19.
And if you're like me, the more you learn, the more you'll worry.
Sequelae are the after-effects of a disease. Encephalopathy is sickness of the brain. But "brain fog" is just one sequela, or potential long-term condition, of Covid-19 being observed. Others include damage to the heart, lungs or nervous system, as well as general aching and fatigue.
The possible consequences also include a lasting loss of smell (anosmia) or taste (ageusia), and more.
We're not even a year into studying Sars-CoV-2, and yet we keep bumping into surprises. To me, though, this one is the scariest so far: This coronavirus - unlike its cousins, the common cold or most seasonal flus - apparently likes to linger. How long these symptoms can stay in our systems remains to be seen.
One German study showed that about two in three patients had heart inflammation 71 days after officially recovering from Covid-19.
Other researchers found many people with damaged lungs three months after getting "well". And this pandemic is less than a year old.
What we want to know is how all those people will fare in five years, or 20. Will they breathe, run, think and taste wine as they used to? But we'll have to wait for those studies.
What does this uncertainty mean for us in 2020? One thing it means is that we can't simply focus on mortality when assessing Covid-19's risk.
For most of this year, those of us who are youngish and free of pre-existing conditions respected but didn't dread Sars-CoV-2. After all, if my children or I get it, we'll probably survive. And then we'll be rid of it and immune for a while. Right?
"Long Covid" challenges that logic. Should I, therefore, worry more now? What is the right way to think about all this?
I've long been fascinated by the proven inability of Homo sapiens to assess risks rationally. The likes of psychologists Daniel Kahneman and Amos Tversky have documented, sometimes hilariously, how we keep falling into mental traps in our everyday lives.
We regularly panic over things that are banal and ignore risks that are grave. Personally, I've always been amazed that many people are afraid of cellphone radiation even as they're merrily fiddling with their iPhones while driving.
The risk of the former is negligible (because the radiation isn't ionising). The risk of the latter is huge, because our brains can't cognitively handle the distraction while also focusing on the road.
And yet the two risks present themselves differently. The radiation is invisible and "does something" to us inside, with effects that might become evident only over time. We feel we have no control.
The effects of distracted driving are visible and immediate: Either we cause a crash or we don't. And we feel we have control because, after all, we didn't crash yesterday or the day before.
Psychologically, "short" and "long" Covid are analogous. When I thought the disease was short and binary - you had it or you no longer had it - it seemed like distracted driving. I put on a mask and washed my hands in the same way as I put on my seat belt, and kept the illusion of control.
The prospect of long Covid feels more like the risk of radiation - or of lead in our paint chips or all the other toxins out there. It can get into us and then stay, stealthily causing unknowable harm.
Subjectively, I feel worse because I no longer have the illusion of control. And unlike non-ionising cellphone radiation, long Covid actually may be serious.
I first wrote about Covid-19 in January, when we didn't even have a name for it. Since then, I've repeatedly pondered why we're so at each other's throats about how to deal with this pandemic - lockdowns or not, masks on or off, schools open or closed, and so forth. It's because we just don't know how to weigh the relevant risks.
The risk that I die against the risk that I give it to you and you die. The risk that by doing too much to stop the virus, we plunge too many into poverty - 150 million, according to the World Bank - who may then suffer and die from something else. The risk that by trying to save the lives of some, we condemn others to depression that makes life unliveable.
The realisation that Covid-19 can be a chronic disease makes all these decisions even harder because it adds another risk conundrum. We now have to weigh the dangers not only of lives ended but also of lives permanently limited. I have no easy answers. But I'm more worried about Sars-CoV-2 than I was before.
• Andreas Kluth is a columnist for Bloomberg Opinion. He was previously editor-in-chief of Handelsblatt Global and a writer for The Economist.