COVID, complexity and face-masks

Healthcare is a Complex Adaptive System, to quote Jeffrey Braithwaite. To be fair, I’d been aware of this for some considerable time, having first discussed the role of complexity science in healthcare associated infection is 2003. However, it was not until 2014 that we began to apply complexity science to our work, as discussed previously in this blog and in more detail in a BMJ blog. I could not think of a better video to offer a simple but relevant illustration of how a complex adaptive system works. If you have not viewed the video produced by the Ohio Department of Health, I would recommend a look because one of the fundamental principles of a complex system is that the outcome is dependent on the starting conditions.

The video illustrates two very different starting conditions. Initially, with the mouse traps very close together, the arrival of the dropped ball sets off a chain reaction. Space the traps out and on this occasion, the chain reaction is not set off. The intention of the health department is to illustrate the effect of the “stay at home” message during this pandemic. It equally of course illustrates the rural distancing that I discussed in my previous blog. I would add that since writing that previous post, my view of the asymptomatic underside of the iceberg that I wrote about on 10th April has been further reinforced. A consultant colleague wrote in an email to me recently that, “We are having many more positive results in asymptomatic patients,” while the BMJ carried a story that suggested 80% of infections are asymptomatic.

Accepting that in any complex adaptive system the outcome is dependent on the starting conditions, then why would we expect the rates of infection and deaths to be proportionally the same in different countries or regions? Yet that seems to be a constant refrain in not only the UK press but similarly around the world. When you throw into the mix a whole series of different variables like how soon after the first case did a country or region move to a lockdown position? When were large gatherings banned? What is the relative distribution of the population? How many people live in a given household? How close are the seats on public transport? How do people in a region or country greet each other? Handshake, embrace or kiss? I could go on thinking of different variables but I hope you get the picture. This is complexity and we reviewed this together in the previous blog when we discussed rural distancing.

So finally he gets to face-masks . . . . .

As a microbiologist, I was never convinced of the value of a facemask to protect myself from infection. The surgical facemask was designed for surgical teams to wear to prevent them breathing on a surgical wound during an operation. Why? Because up to 30% of the population carry Staphylococcus aureus in their noses and various streptococci to a lesser extent. Staph. aureus is the main cause of wound infections. By wearing the facemask the surgeon is reducing the risk of her patient getting a post-op wound infection.

However, there is a study in 2013 that shows how a surgical mask worn by someone with influenza virus can reduce the detectable levels of virus particles shed. Earlier this year, a paper in Nature Medicine described a similar finding, which included the effectiveness against seasonal coronaviruses.

As a result, the US Centers for Disease Control and Prevention recommend the use of face coverings in certain situations. The World Health Organisation recognise that a facemask is effective if caring for someone with COVID-19 or if you have symptoms, by preventing transmission to others. This advice is not specificallyabout wearing facemasks by the public when out and about.

UK government advice is to recommend face coverings in certain situations.

The Chief Medical Officer for Wales has advised the wearing of facemasks by the public should be a matter of choice. Dr Atherton says:

“So what do we know about the use of non-clinical face coverings for the general public? The evidence from SAGE shows a small, but marginally positive effect on reducing the risk of a coronavirus infection in others.

“We know that you could be infectious even if you don’t have symptoms – so could people around you. When someone with the virus coughs or breathes, the infection travels through the air in droplets and lands on surfaces. If you’re wearing a cloth face covering over your mouth and nose some of the droplets will be stopped by that mask.”

If you choose to wear a face covering, please think carefully about the risks:

This website always seeks to explain risks and help you make risk based decisions.

Firstly, if you know you have respiratory symptoms then please stay at home. The stay at home message has been extremely successful in flattening the curve and remains the reason why the public has saved the NHS from being overwhelmed.

Respiratory symptoms are however very wide as I previously discussed and a non-infectious cough can go on for some weeks after an acute infection, such that it may not be obvious and you therefore feel there may be benefit for others if you wear a face covering.

So here’s my advice if you have chosen to wear a face covering:

• Always use a clean/laundered item – this is so you know you are not putting yourself at risk.
• Wash your hands or use hand sanitiser before you put on your face covering
• Take hand sanitiser with you when you go out – this is in case you remove your covering before you return home.
• If you remove your mask before returning home, fold it so the inside of the mask stays inside and put it in a pocket or bag. Please do not litter and do not dispose of publicly.
• Use your hand sanitiser after removing – this stops you contamination surfaces if you were shedding virus or protects you if someone has contaminated your face covering while you are out and about.
• Do not reapply that face covering. It must be laundered before reuse or disposed of when you get home.
• If you know you are likely to remove the face covering when out, then you could plan to take one or more clean items with you. This will require “pocket discipline” to know your clean from dirty.
• When you get home, remove your mask and either place it in a laundry container or put it straight in a washing machine.
• Wash your hands after handling your face covering – this is so if there is virus on the covering, you will not transfer it to surfaces in your home and put others or yourself at risk.

As SAGE has said, there may be a small effect from your actions. In a complex adaptive system, small effects undertaken by many people can influence the behaviour of the system, which in this case may help to reduce transmission. Hand hygiene, cough etiquette, social distancing and staying at home when you clearly have respiratory symptoms remain the mainstay of protecting ourselves and others.