As I may have suggested in the past, a bear of very little brain needs simple instructions to help him to stay safe. The problem with simple instructions is that they often fail to provide the full picture. Sometimes, a change of advice can lead to mass befuddlement and chaos (and you get bigger r’s). So, how far apart do I need to be from people not in my household in order to stay safe?
Quick reminder of the rules in the UK. England and Northern Ireland say we should keep 1 metre distant from each other PLUS. Wales and Scotland say 2 metres.
If you look at the rules in England and Northern Ireland the PLUS bit means you need to take extra precautions, and the NHS recommendations still say 2 metres.
So what does the science say?
A quick search of Google in the UK will probably lead you to an article headlined ‘Rigid social distancing rules for covid-19 based on outdated science’. This is from the British Medical Journal. (https://www.bmj.com/company/newsroom/rigid-social-distancing-rules-for-covid-19-based-on-outdated-science/)
This might make you think that the strict restrictions we are under are not actually based on reliable, modern, science, so we shouldn’t worry about them. That’s what happens if you don’t click through and read the whole thing.
A quick history lesson (very). The 1 to 2 metre distancing rules come from expriments done in 1897 by Carl Flugge. He looked at how far droplets carry when you cough, sneeze or speak and worked out that pathogens could only travel a short distance (as far as could be seen using the science of 1897).
In the 1940s, high speed photography allowed scientists to look at this in more detail. A study in 1948 of haemolytic streptococci spread (why not something easier to say?) looked at coughs and sneezes (which spread diseases) and showed that 65% of people produced large droplets which only travelled 1.7 metres on average, though 10% managed 2.9 metres!
You wait, time passes… In more recent studies using more sensitive equipment droplets have been found to travel 6-8 metres.
So what about the spread of COVID-19? Recent COVID studies have found droplets will travel further than 2 metres, confirmed multiple times by multiple teams. It’s about the size of the droplets produced during sneezing, coughing and speaking. Smaller droplets travel further. It seems that people infected with COVID-19 produce smaller droplets.
Does this mean we are only safe if we are 8 metres from one another? Tell me what the safe distance is so that I can maintain it. I need simplicity.
Hold on a moment. I am sorry to tell you that it is just not that simple. There are other factors that can help or hinder the spread of the virus. These are the Environmental Factors. We need to consider number of people, air flow, time AND distance.
Stay with me. Let’s look at some examples. Outdoors, in an area of reasonably low concentrations of people, with good air flow, the risk factor is greatly reduced. 1 metre apart, wearing masks, outside, is probably (no guarantees) not going to put you at a huge risk. At 2 metres in the same setting your risks are even smaller.
Outdoors at a big event, with lots of people together, at least 1 metre apart, but with good air flow and for a short period (a maximum of 15 minutes has been suggested), if you are wearing a mask and washing your hands etc, the risk is still not that high. However, this only applies if everyone is silent, or talking quietly. Once you start to sing or shout the risk factor shoots up! So, coming to see me do a stadium comedy tour – probably safe, watching your favourite team play rugby – probably unsafe.
Indoors, in a well ventilated location, with all precautions taken (masks, keeping 2 metres apart and talking quietly) plus keeping social interaction outside your household very short it is still a low risk. Poor ventilation and longer interactions makes this much more risky.
What about without face coverings? Keep your interactions short, don’t sing or shout, keep at least a metre apart and it is still much riskier, but not as risky as being too close or in a poorly ventilated place.
So, it is more complicated than most people realise. Social Distancing only works if we also keep our hands (and faces) clean, make sure we are in well ventilated locations, keep occupancy low, don’t sing or shout (or cough or sneeze), wear masks and keep our interactions short. This starts to sound terrifying, but it doesn’t have to be. Hands – Face – Space as the UK Government has put it. Wash your hands, wear a mask on your face and keep 2 metres apart. It is still good advice, and simple enough to follow.
STOP PRESS: I wanted to add a little bit here that points out that this still seems to be too complicated for some people. To them I say ‘Stay at Home, Save Lives’. If you can’t handle nuanced advice, stick to the simple stuff.