Social distancing: Why it’s important, and why we find it so difficult

Social distancing has been in the news a lot in the last few days here in the UK, mainly because we Brits seem to be very bad at it! Friends in countries that are locked-down, like France and Spain, are telling me how shocked and horrified they are by scenes this weekend of crowds flocking to parks, beaches and beauty spots. The UK government is threatening lock-down unless we start to take things seriously. In this post, I will discuss why social distancing is important, and some possible reasons why we are finding it so difficult.

Exponential growth curve for hypothetical ‘Virus X’.

Why do we need social isolation? Let’s think about how disease spreads. A person gets infected with a disease, we’ll call it Virus X. That first person to be infected is called Patient Zero. On the first day, Patient Zero infects two other people. On the second day, they each infect two more, and so on. After a week, we have 256 patients.

If each patient infects 5 people a day, then after one week there will be 78125 people with the disease. If each infected person passes the virus on to 10 people, then after a week there will be 1 million with the disease. You get the picture. This process is called exponential growth and is shown on the right. If the shape of that curve is familiar, it’s because you have probably seen it on graphs showing the number of cases of COVID-19 in the UK, like the one below.

Cases of COVID-19 in the UK. In blue, you can see a classic exponential growth curve.
Comparing the spread of ‘Virus X’ with and without social distancing.

How does social distancing help? Basically, unless an infected person is in close contact with someone else, they can’t spread the virus. Exponential growth will still occur, because there will always be some in the population who cannot practice social distancing, i.e. key workers. But the rate of exponential growth will be much slower. This is known as ‘flattening the curve’ and is shown on the left.

An additional consideration is that although discoveries about COVID-19 are being made at an unprecedented rate, there is still a lot that we don’t understand. When you get an infection, it will be several days before you start to show symptoms; this is called the incubation period and varies between different pathogens. When the level of the pathogen in your body drops below a certain level, your symptoms will go away; but you are not yet fully clear of the infection.

A few people have asked me why this pandemic is so different from the 2009 Swine Flu pandemic. With Swine Flu, we were dealing with a new strain of a very well understood virus. In particular, it is known that influenza viruses can only be passed on to other people by patients who are symptomatic. During the incubation and recovery periods, patients cannot pass the virus on except under exceptional circumstances. This meant that only those who were actually ill needed to be isolated. In addition, it is known that patients who recover from influenza viruses will then be immune to the disease.

With COVID-19, the incubation period is up to 14 days, and we still don’t know at what point patients become infections. We also don’t know how long it takes for recovered patients to cease to be infectious, and whether people who have recovered have immunity. We need to know whether immunity develops; how strong it is; and how long it lasts.

Look at the two diagrams below, showing the spread of the hypothetical Virus X through a population. On the left is the situation on Day 1, on the right is the situation after one week. The top diagram shows a population that is not practising social distancing, the bottom diagram shows a population that is. Speaks for itself, doesn’t it?

So, why is social distancing so difficult? Especially for us Brits, who historically have a reputation for doing as we are told. One reason is that we are having to break habits that have become ingrained over many years. Take this scenario: you are in a queue at the supermarket. The person in front of you moves forward, what do you do? You move forward too, to close the gap. This is not neccessarily deliberate, it’s a habit, and changing habits requires conscious thought. The good news is that it doesn’t take long for new habits to develop. I went shopping today (because I needed to, I hasten to add), and everyone was keeping their distance in the queue without needing to be reminded.

Another reason is people are used to freedom of movement. It’s a sunny spring weekend, the kids have been stuck in the car, let’s go to the beach because social distancing means no one else will be there. Unfortunately, hundreds of other people have had the same idea, and when you get there, it’s heaving. Do you have the strength of mind to turn the car round and tell the kids we aren’t going to the beach after all?

Recent panic buying is not helping either. Those of us who have continued to shop sensibly and responsibly have found that due to panic buying, we have had to visit multiple shops to get the basics. I’m trying to practise sensible social distancing due to my asthma, but it’s difficult when you have to visit 3 different shops to find toothpaste! Thankfully things seem to be settling down a bit. This morning I went to a local supermarket and was able to pretty much get my normal weekly shop, much to my relief!

Possibly the biggest barrier to social distancing, though, is the fact that we are primates, and by and large, primates are social animals. Our brains are not wired for isolation and I know I am not alone in worrying about how this will affect my mental health. However, there is a lot we can do to combat this.

The good news is that we live in an age where technology has made it easier than ever to keep in contact with friends and loved ones. So take advantage of Facebook, Zoom, WhatsApp, Skype and everything else that’s out there. Reconnect with people you’ve lost touch with. Share memories of good times! And keep remembering, social distancing isn’t forever; and the better we are at it, the less time it’s likely to last.

In the next couple of days I will be posting some ideas about simple experiments you can do at home to engage children with science while they aren’t at school, so watch this space! As always, if you have specific questions or concerns you’d like me to address, let me know. Stay safe and well, everyone.

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