How Long Must Social Distancing Last To Flatten The Coronavirus Curve Enough? Benjamin Way Follow Mar 27 · 5 min read

The question on everybody’s mind! You are not going to like the answer.

As of this writing, 46 states have closed schools as part of social distancing protocols. 21 states have urged their residents to stay home if and whenever possible. Non-essential businesses across the country have been ordered closed, leaving a lot of people out of work or with reduced hours — although this has been offset somewhat by certain businesses going on hiring sprees. This has all happened so quickly, and continues to develop, that we do not even have employment numbers yet. Many of those less affected are suddenly working from home… or trying to, while their kids are stuck there all day with nothing to do.

As a slightly unnerving sense of familiarity settles over the quieted streets, we cannot help but wonder: how long does this need to go on?

Some government and businesses leaders are pressing for a very early release from social distancing protocols. Medical researchers and workers are saying that we probably have to tighten the screws.

I understand that social distancing protocol is expensive, but it is definitely worth the cost, at least in the short term.

Still, even if we are totally on board with making any length of sacrifice to save the lives of our compatriots and perhaps ourselves, we would like to know how long this is supposed to take.

If you don’t know about “flattening the curve,” here are some resources. The point of social distancing is to reduce the overall spread of the disease, and to space out the cases over a more manageable span of time.

The problem with most of the graphics and memes floating around is that they do not accurately depict the scale of the difference between our hospital capacity and our predicted hospital needs.

For example, in this illustration, it appears that we would only need to reduce the peak number of cases by about, like, 70% in order to avoid reaching capacity at our hospitals. That sounds like a lot, but it’s not so bad, really, compared with what I am going to tell you next. We don’t have nearly enough beds.

Let’s consider the estimates for hospitalization in this model that actual hospitals are supposed to use to prepare for the epidemic.

5% of people will need hospitalization.

2% of people will need the ICU.

With a population of 330 million, that gives us the following table for various rates of total infection:

Right now, we have about 265k hospital beds available, of which about 31k are ICU. For this model, I will not consider cannibalizing beds from other hospital needs to treat COVID-19.

Okay, so in order to avoid additional mortality from hospital overflow, we need to get through all those potential hospitalization cases without exceeding those bed limits. Here’s the minimum number of batches we will need at those same infection rates:

Hospital recovery time for this virus ranges from 3–6 weeks. Let’s take the liberty of giving ourselves a mildly optimistic 4-week average. That produces the following chart:

This is not good. At the very optimistic supposition that only 5% of people will eventually catch the virus, we would still need about 9 months of perfectly calibrated curve flattening to guarantee enough room in the ICU.

What ultimate rate of infection should we expect? This professor of epidemiology says we can easily expect 40–70% of the world’s population to contract COVID-19.

That puts us in the range of needing at least 6.5 to 10 years of virus suppression measures to guarantee that nobody who needs the ICU would be crowded out of it.

Remember that rosy “flatten the curve” graph? Here’s more like what we actually need to make it look like.

“Sorry, wait, go back? Did you just say 6.5 to 10 years of social distancing could be required?” you might be asking. You might be adding another four letters or more to go with it.

Sadly, it needs to be recognized that achieving that goal in so few (LOL!) years would be an amazing statistical feat, because it would mean flattening the curve to be literally flat, exactly at the level of our hospital capacity. Given that this is a virus with a two week lag in detection and an exponential growth curve, maintaining it with such precision is virtually impossible.

This means that we would choose one of two distasteful options. Either we have to give ourselves a buffer of empty beds and extend the quarantine long enough that the PEAK number of cases is below hospital capacity (note that the peak is likely to be at least twice the average, requiring at least double the quarantine), or we have to accept that at the peak of the epidemic, a lot of people will die at home because they had no medical care.

So, all of that together means that really what we are doing is trying to stall the spread of the virus until we can treat, cure, or prevent it better to reduce mortality rates as everyone is eventually exposed to it.

This new normal is likely to go on until either we have developed a vaccine (which will likely succeed but take at least 18 months), or a treatment or a cure, neither of which is in any way guaranteed, or until most people have already gotten the virus anyway, or until business and political leaders convince everyone the expected deaths are worth the profits we could possibly be making if we reopened everything right away. Depending on the results, we may, two weeks after that, go right back into quarantine.

But, who knows? We are still in the very, very early stages of studying this virus, and our understandings could change dramatically over a couple more months of research. However, that’s a chicken that I am not going to count until it hatches. Paying for those two months of research would definitely be worth the peace of mind, even if the risks we presently perceive turn out to have been overstated.

For the meanwhile, it’s time to hunker down and prepare for a very extended stay at home. A year and a half might be the only responsible thing to do, although this will be a fun experiment to see how fast they can rush production of a vaccine. Chess tournament, anyone?