Before SARS-CoV-2, there were already several coronaviruses that infected humans. They circulated in the population giving us colds. What’s so different about the novel coronavirus that makes it cause potentially deadly Covid-19 instead of a cold? There are a few hypotheses being explored, but the frontrunner is the idea that there is nothing of any importance different about the new viruses. The difference is all in humans.
The theory is that exposure to coronaviruses when we are children is important to equip our immune systems to correctly respond to future infections with the same virus. Get infected with a virus that our immune system remembers from our youth, and we’ll get a cold; get infected with one that we’ve never encountered before and we might get something much worse.
From this, a few hypotheses follow. Perhaps each of the “common cold” coronaviruses were deadly when we first encountered them — there may have been a series of coronavirus pandemics of the millennia as each one made its first jump to humans and tore through the population of naive adults.
Equally the theory provides grounds for hope: a new generation will grow up being exposed to SARS-CoV-2 during childhood, and when they become adults their immune systems will be correctly tuned such that each time they encounter the virus again, it causes nothing worse than a cold.
In the meantime, of course, we will need to protect the older generations that are vulnerable — reduce their chances of encountering the virus, and give their immune systems all the help we can to recognise it with vaccinations. But if the theory is correct, once those generations are gone, Covid-19 is properly over.
But perhaps there’s another thread of hope we can grasp from this theory?
It feels like humanity and civilisation are facing lots of other threats right now. For those of us who have taken it for granted that we live in wealthy, stable democracies, recent events have bombarded us with reminders of how shaky our foundations can be, how flimsy our institutions are, and how easy it is to manipulate our media and collective understandings of reality.
Our connected world has allowed novel threats — from astroturfs to botnets, scams to secret ad targeting, fake news to deep fakes — to rip through a naive population that is vulnerable to them. But new generations are growing up alongside these things. They will not be so naive to the threat. In this population, will the forces of manipulation be able to cause a deadly disease, or just a common cold? I’ll leave you to think about how various recent votes around the world have been so dramatically split along generational lines.
That leaves us with just one problem: as long as the boomers are still with us, we need to keep case numbers from getting out of control and overwhelming our vulnerable democracy. Please, shield your vulnerable older relatives from Facebook, and make sure they immunise themselves against its content.