Some Scary Thoughts About Viruses

     There was no vaccine for chickenpox when I was a kid in the 1970's, and it was considered inevitable and indeed preferable to catch it as a kid, since it tends to be more serious to catch it as an adult. I remember it as both a novelty and an inconvenience; sure, I itched a bit, but no big deal, and I knew it would go away soon enough. Most people my age have a chickenpox scar or two, but it was really no big deal.
     And that's to be expected in a virus that's been circulating in the human population since forever. There's a principle in evolutionary biology: parasites tend to evolve towards becoming symbiotes over time. That's because parasites eventually need to spread their offspring to new hosts, and if you kill off your host too quickly, you may find it harder to find new hosts to infect (unless you evolve some kind of complex life cycle that involves infecting the animal that eats your current host.) Chickenpox doesn't significantly impact the survivability of the average human child who catches it, so it has plenty of opportunity to infect lots of other human children.
     But humans have immune systems, and quickly fight off chickenpox within a week or so, and in the process learn to recognize the zoster virus so you're typically immune to it for the rest of your life. And this is a bit of a problem for zoster, because if it spreads rapidly through a small group of hunter-gatherers, and then everyone is immune, the virus has no new hosts to infect.
     Zoster has a clever solution, which I learned about last year. See, you don't actually get rid of the virus entirely. Some of them find their way into the nervous system and hide out there for a few decades, and then make their way back down to the skin and appear as a new disease: shingles. This means that the virus has a whole new crop of young people to infect, who were born after the last outbreak ended. And so the virus persists well into the future.

     The virus that causes Covid-19, named SARS-cov-2, had been circulating among some population of bats for a long time, but it only entered the human population about five months ago. That means we have no idea whatsoever what its long term effects are. Most people only suffer a minor cold-like infection and get over it -- we think. Many people have had it and recovered -- we think. But we just don't know what's going to happen one or ten or thirty years after exposure. The initial infection with HIV is very much like coming down with the flu, and clears up after a week or so and is forgotten, but then can take ten years or more before it damages the immune system enough to develop into AIDS. For all we know, people who've "recovered" from Covid-19 might suddenly start dropping dead of mysterious blood clots, six months after getting the all clear. There have, after all, been reports of higher rates of strokes and heart attacks, and strange blood concentrations in the toes of young people; the virus does seem to be having some kind of effect besides just causing respiratory problems.

     For that matter, maybe they develop superhuman endurance and a ravenous hunger for human brains, and this is the start of the zombie apocalypse for real.

     Now, I don't think that's likely at all. I'm not a biologist or a physician or an epidemiologist, but I suspect that we probably won't see too much in the way of unexpected long-term effects from the virus. But the point is that we just don't know right now.
     If we assume that Covid-19 is just a really, really bad cold that kills 1-2% of the people who catch it, then you can sort of make the argument that once we've had enough people get sick and recover, the health care system can handle anyone who gets infected later when we ease all the mask wearing and social distancing rules. We haven't reached the point where that's a good idea yet, but you can make the argument.
     But I argue that since we do not know what else this virus may do in the long run, we should therefore be a little more cautious about opening everything up than we would be if we knew this was just a very bad cold. Spreading out the infections over a longer time is better than having them all at once, even if everyone is eventually infected, but it's still better yet never to be infected at all, especially with such a new and poorly-understood virus. So I urge patience. Let's beat this thing.