It's something I like to keep in mind after a big workout, particularly on the legs — get the weight off them!

Stand sit lie

When studying rates of infections, notably with measles, researchers have seen that in cases where a sufficiently large proportion of a population has been immunised or developed protection against a disease then infection rates also reduce in unprotected members of the population. In other words, the unprotected members appear to receive some indirect protection from the protected members of the population. This effect is known as herd immunity and is a tantalising goal for reducing the prevalence of epidemics.

While appealing in theory this article in Nature provides Five reasons why COVID herd immunity is probably impossible. These include:

Uncertainty around whether vaccinations prevent transmission. For example, herd immunity works when diseases can't be passed between protected members of a population to the unprotected. With COVID-19, vaccines seem to reduce symptoms but may still allow transmission.

It's also challenging to get vaccines evenly to all areas. These combined with complications brought by new variants, immunity fading before widespread vaccination is achieved, and people changing their behaviour — say, mixing more widely — once they've received some protection, means COVID-19 may be more likely to be something we live alongside rather than eradicate.

Herd immunity

Despite all our best intentions, accidents happen. Analysis of accidents in large complex systems such as power stations or plane crashes led to an understanding that "no one failure, human or technical, is sufficient to cause an accident. Rather, it involves the unlikely and often unforeseeable conjunction of several contributing factors arising from different levels of the system."

James Reason's Swiss Cheese Model is a memorable visual metaphor that illustrates how each safeguard may contain a latent flaw, or hole, and that an unfortunate circumstance, may result in these holes lining up to disastrous effect. It's also a nice reminder that multiple layers of defence will be more effective, but even with our best efforts, there's still potential for something to go wrong.

Excerpt from Revisiting the "Swiss Cheese" Model of Accidents (pdf), Reason, Hollnagel and Paries, 2006.

Coronavirus example from the Cleveland Clinic.

The Swiss Cheese Model

Writing this in the middle(?) of the coronavirus outbreak I thought it might be interesting to share these charts, created from the simulations in the excellent Washington Post article “Why outbreaks like the coronavirus spread exponentially, and how to ‘flatten the curve’” by Harry Stevens.

The charts represent different strategies for containment and mitigation of the effects of a contagious outbreak.

Trying to quarantine an area — where it is difficult to attain complete quarantine — delays the effect of an outbreak somewhat, but once released the impact is still significant with a potentially high peak of cases.

Social-distancing — staying away from each other to reduce the chance of infecting others if you are infected and minimise the chance of infecting yourself — in both the bottom scenarios in the simulation manages to both delay the onset of an outbreak and reduce the peak. Not included in this simple simulation is that reducing peak infections in particular helps the healthcare system effectively treat and care for those who are infected, and look after its healthcare workers. When healthcare is not overwhelmed this further minimises both the spread of a disease and fatality rate.

Read the article, run your own simulations, and maybe consider supporting the Washington Post, here: “Why outbreaks like the coronavirus spread exponentially, and how to 'flatten the curve’”.

Disclaimer: I am not a public health professional. These charts are from my results of the simulations in the article and the simulations represent a simplified, though instructive I think, view of an outbreak and these containment methods.

Flatten the curve of an outbreak

In these times, and to be honest most times, washing your hands well is one of the very best things you can do to keep yourself healthy and free from infections.

You should use soap if you have it, it should take about 20s, and if you follow these steps you’ll cover pretty much all of the different parts of your hands. In standard, cursory handwashing it’s very easy to miss what ought to be obvious places to clean like your fingertips. Then try to avoid touching taps and door handles on your way out of public places.

I find doing these steps takes about 20s, but to make sure you could also try singing a song segment you like. NPR has some suggestions: Keep flu at bay with a song.

Some other hygiene sketches to bear in mind:

Sneezes and coughs are powerful things — a sneeze can travel up to 8m. So always make sure you do your…

Dry your hands with only one towel. And as a basic rule…

The handwashing guidance is from the wonderful NHS.

How to wash your hands

I was taught this originally for backpacking but it really always makes sense once you think about it. Pouring onto a hand keeps dirty hands out of the rest of the snacks in much the same way as a drinking fountain manages to be hygienic by shooting out the water.

Some alternative sides to sharing: compliments are gifts and give gifts others can give. And two more about germs: sneezes and coughs, and the Dracula sneeze.

Pour, don’t dip when sharing snacks.

I love this term. From the Japanese shinrin-yoku, it means to soak in the atmosphere of a forest. And I think it’s not too far of an overstatement to say that a walk in Nature is about the closest to a miracle cure we have. There appear to be myriad benefits from simply spending time in Nature. As my sister put it, if it was a drug we’d be prescribing it.

Though we didn’t call it forest bathing at the time it’s definitely some of my happiest memories, like here, here, here, here, and here.

Forest bathing

‘Tis the season for these powerful things. Turns out sneezes can travel up to 8 m, coughs up to 6m and they can linger in the air for up to 10 minutes.

All the more important to make sure you’re doing your Dracula sneeze into your sleeve.

Sneezes and coughs

One of the best virtuous circles. One of my more surprising recent reads has been Novak Djokovic’s Serve to Win about diet, discipline, going gluten-free and physical and mental excellence. The guy certainly knows about excellence and it was neat to learn his philosophy on eating — the book contains recipes — and taking care of yourself including some serious respect for sleep. This sketchplanation is just one of the reason’s why. Since reading it I’ve put an alarm on every night to remind me to respect sleep. Night!

The virtuous cycle of exercise and sleep

Venomous animals inject venom through bites, stings and the like. Think snakes, spiders, stingrays…

Poisonous animals poison you if you absorb - perhaps by touching the skin of a poisonous frog - consume - perhaps by eating a poisonous animal - or inhale the poison - perhaps by breathing in some poisonous spores. Think amphibians, plants, fungi…

Venomous, poisonous - what’s the difference

Sneezing into your sleeve helps prevent the spread of cold and flu germs.

Dracula sneeze

Seriously, I am not qualified to give medical advice. This is not a recommendation. Seek advice from your doctor. We have been told this from ours several times.

Alternate ibuprofen and paracetamol

We’ve been looking for the right size plates for some time.

Smaller plates help you eat less

Learned from Joe Smith’s short entertaining TED talk: How to use a paper towel.

Sketchplanations tagged with health