I’ll start with a few “FAQ” type things (I will edit this post a few times this morning as I duck in and out due to meetings, so I’m going to “post” now at 9:30AM EST and then come back and edit more…if you have any specific questions that you’ve heard, maybe type them below and I’ll address them in this post if I can):
What’s the big deal? I heard this is just like the flu.
It’s natural to reach for the “flu” comparison here because it’s the nearest thing most people can liken it to. There’s some merit to doing so, but the downside (IMO) is that a lot of people already downplay or misunderstand “the flu” (e.g. they conflate “I had a bad cold and stayed home for a few days” with having diagnosed influenza) and so probably think seasonal flu is just something we all get every year and it’s fine.
From what I’ve read, seen, and heard so far, there are a couple of things to know about “the flu” versus the novel coronavirus. The first is to understand that since this is a novel disease, it’s so early that we don’t know much about how it behaves yet, and that is at least part of the reason for excess caution at this time (along with Italy, which we’ll get to shortly). With seasonal flu, we basically know the ceiling for just how bad it gets; with COVID19 we’re still figuring out what we are dealing with here, but there are reasons to believe it could be much worse than just a bad flu season. Let’s unpack some of the reasons why that is.
Case Fatality Rate
The first and seemingly simplest question one might ask about a new disease are “what are the chances someone who gets it will die?”
For reasons you’ve all read and thought about, it’s not a trivial task to pin down the CFR during an outbreak of a novel pathogen. We aren’t testing for it early on; even when we are testing, it’s possible that lots of people get it and don’t realize it (e.g. ride it out at home with a “bad cold”) and we’ve invariably testing the worst cases, so getting a precise estimate of the CFR is really tough in the early days. An imperfect but still (IMO) useful piece of information is the fatality rate among those who actually felt ill enough to seek hospital care - though it will overestimate the true/overall CFR, if that is much higher than for other known pathogens like seasonal flu, it at least tips us off that we’re seeing something that’s bad conditional on the patients feeling bad enough to seek care. We’ll discuss the health systems issue below, but even if the overall CFR is really overestimated right now because of the possibility that lots of people are walking around with no symptoms or mild symptoms and we’re only seeing the worst cases at the hospital, the fact that ICU’s are getting totally overrun with cases in some regions means that we still have a problem even if the CFR is low once you account for all of that. It’s little comfort to hospitals to be told by armchair commentators that the CFR ISN’T ACKSHUALLY THAT HIGH when they’re seeing patients die in front of them because they don’t have enough ventilators.
The best guess right now is about 1% in a system where patients can be adequately cared for (with acknowledgement that this could be much lower if there are tons of us walking around that already “had this” and just experienced it as a bad cold).
Lots of conversations about “R0” numbers these days - just how many new cases spring from one index case? This again is a useful summary measure but also simplistic (highly context-dependent) and hard to calculate in an outbreak of a novel agent without widespread testing.
What we do know is that seems to spread relatively easily, enough so that a few cases going to a conference can generate a whole bunch more cases, and that’s concerning enough that it’s a prudent idea to minimize big gatherings in confined spaces at this time. It’s probably not “walk past someone on the street and you’ll get this” but it certainly seems to be something you can get from shaking hands or touching common surfaces.
This is the biggest issue and one I’m going to return and update later, because it’s probably the most important thing to understand to grasp why this could be a public health disaster
We don’t even have that many cases where I live yet, so why the massive lockdown?
See above re: health systems and early unknowns. The major concern isn’t that Allegheny County (where I live) has 12 cases today; it’s that we might have 100 cases a week from now, 250 the week after that, and 500 the week after that; at this point we’ve probably exhausted the supply of available ICU beds and ventilators, which means hospitals and ICUs have to start making decisions like “COVID19 patients over 60 years old don’t get ventilator support, we have too many patients and need to spend the resources on people with the best chance of survival” which is how the CFR that’s 1% under normal conditions with sufficient care available creeps up towards 7-8-9% as is happening in Italy.
One other note that occurs to me - the clinical course of this disease seems to require that patients who do advance to needing ventilator support tend to need ventilator support longer than other comparable diseases/patients, which is another challenge here. The “number of cases” isn’t the only thing that matters here. The same number of cases will stress the system differently if all of the cases need to be on a ventilator for 14 days versus 5 days.
But just the elderly are at risk, right? Why do young people have to stop what they’re doing too?
Two things here. For one, it’s true that the elderly are at much higher risk than the young and healthy, but the risk to non-elderly is still greater than zero; my Twitter timeline is full of stories of deceased 40- and 50-somethings from COVID19 (admittedly there have been very few deaths to date in 20-somethings).
The second is the fucking shocking degree of callousness this seems to show towards people older than you. Whenever I see some dipshit teenager on spring break getting interviewed and saying “So what, if I get the corona I get the corona” - don’t you have parents? Grandparents? Friends that are older? Do you not understand that if you get the virus, come home and give this to them, it could be curtains for them? We can’t prevent all deaths from all causes, I get that, and as alluded (though I don’t really wanna go there in THIS THREAD) there are going to be some really complex social consequences with respect to people losing income (not just the rich, but the wait staff, day care babysitter, gig musician, wedding caterer, etc) and fallout from that. But anyways, I’m not a fan of the “so just the elderly get it, what’s the big deal?” line of thinking I’ve been seeing from young folks.