Coronavirus: is the UK’s 1% mortality projection credible?

Italy has twice as many intensive care beds as us. And they’re struggling despite trying to contain the outbreak. We’re going to need more beds!

Yesterday I wrote about the UK’s approach to the outbreak. I’m doing my best to believe it is a good plan, to convince myself it can work. The numbers alarm me, the mortality rate most of all.

The questions I’m asking are:

•  How many people might need intensive care?
•  Over what time period?
•  Do we have enough beds?
•  Can the most vulnerable in society be protected?
•  Can the government’s plan limit mortality to 1%?

The China Centre for Disease Control and Prevention reported that 4.7% of cases required intensive care. Now, it seems to me that the real number is probably lower because a lot of people only get a mild disease so aren’t counted because of testing bias, making the crude rates for intensive care and mortality appear worse than they really are. And this effect would be even greater in the event you let it run through your population as the UK intends to do, as most people will overcome the disease without being tested. Indeed, the UK has stopped testing community cases, presumably because the numbers are becoming impossible to manage.

The stats we see reported in the UK are now going to reflect only the most seriously ill. So the proportion who actually get sick enough to need intensive care might in fact turn out to be lower than the crude stats suggest. Might we be optimistic and assume it’s not 4.7% of the infected who need intensive care then, and the real number of infected who require intensive care might be more like – and I’m speculating – 2%. Let’s proceed on that basis but if you’re a super optimistic person you can halve my figures in your head and assume only 1% will need intensive care.

The UK’s plan is for at least 60% of the population to get the virus. That’s 40 million people. The government’s plausible worst case scenario is higher at 80%. We’d best hope that doesn’t happen. At 60% they hope to achieve some kind of herd immunity going forward. And it’s on this basis that they are not yet closing schools, sending employees home, closing leisure activities, and banning mass gatherings etc. If 2% of the infected need intensive care then that’s 800,000 people. That will be too many.

We are already more than 4 weeks in and the government anticipate the peak of the bell curve could be another 14 weeks away. If they can flatten out the curve and push it out then the curve would be skewed to the right. Optimistically then, the total curve might last something like 45 weeks which would carry us to Christmas, with new cases being far fewer in the autumn and winter period on the curve. If we go along with the government’s strategy to let people get infected then it is a good thing if you can spread out the infections over a long period of time, as well as delaying to the summer.

At the start of this year there were 4,123 adult critical care beds, 3,423 were occupied (83%). Spare capacity is 700 then. But let’s assume we clear around half of those occupied by stopping new operations, taking bigger risks and delaying the virus until spring/summer. You cannot clear them all because people have heart attacks, strokes, get stabbed and so on and such people require intensive care too.

RFA Argus is the Royal Navy’s hospital ship. Might it lend a hand with the outbreak?

By freeing up what beds we can we might have something like 2500 available beds for coronavirus. And let’s assume that the government quadruples the number by throwing money at it, repurposing non-critical wards, deploying the resources of the armed forces, commandeering some nursing and care homes, everything we possible can do to increase beds and equipment, we do it. We make 10,000 beds available for this. This is a hugely optimistic number it seems to me, but let’s go with it.

Now let’s assume we get all the respirators we need, and the beds are staffed by doctors and nurses from other disciplines, retired nurses, trainees doctors, care assistants, army medics, maybe even flying staff in from other places in the world who manage to crush their outbreaks.

 

Even so, there seems absolutely no way the NHS can handle 800,000 people through intensive care in that time period. But the government are predicting a 1% mortality rate. I can’t see how that can be kept so low unless the number needing intensive care turns out to be much less than 2% of those infected I’m speculating about.

Spreading the infections by flatten the peak helps intensive care cope but to reduce numbers into intensive care you also need to work very hard to protect the most vulnerable. Total dedication to protecting the vulnerable is going to be required. This will be critical if we are to keep the mortality rate anything like as good as 1%. So if the government’s prediction is correct then there will need to be significant measures to protect the vulnerable and lower the number who need intensive care treatment.

Actually this is starting to make a bit more sense to me. Protecting the vulnerable is the single most important thing if this plan is going to work. 1 in 5 people in the UK are over age 65. And most don’t work. So you don’t have to shut down the economy, you just isolate the 20% of older people. And of course those younger with health problems. I do worry the government will not do enough to protect this group. It is essential they identify who is most vulnerable and give them specific advise and support.

But if you need to isolate the old and sick and for quite some time while those younger and healthier catch the virus and create (hopefully) herd immunity then you actually want to wait to do this until the rate of transmission is becoming quite rapid – this requires most people to continue to go to work and school. Only once the virus is spreading well do you then isolate the vulnerable while it transmits between the young and healthy still. You don’t want to isolate them too early because it reduces compliance over a lengthy period, so you do this when the risk of catching the virus is at its highest.

You want the vulnerable locked down and you want the virus to spread quickly and extensively while they are. Else you end up with 800,000 people needing 10,000 intensive care beds. If the plan works then the number in fact needing intensive care will be much lower and far fewer people will die as a result. Get it wrong though and the numbers will get out of control fast. The cost would be hundreds of thousands of lives.

The government’s 1% mortality rate still looks very optimistic though. It assumes control and looks like a best case scenario. It seems to me that 2% would be a very good outcome even with the introduction of better measures to protect the vulnerable. 2% mortality of those infected would mean 800,000 people dying in the UK. Hopefully that doesn’t happen. 1% is bad enough.

So yeah, I can see how the plan could work. But usually what works on paper rarely plays out quite as you hoped. Even if it does there are still questions about whether this really is necessary, whether herd immunity will result, and whether shutting down like every other country is doing might in fact prove to be a better idea. I’m still not entirely sold on the government’s strategy but I respect the plan a bit more than I did previously.