Skip to main content

Should You Wear a Mask?

The short answer for the general public: it's up to you. The Surgeon General says it's a bad idea for most people who aren't sick because people touch their face more when they're wearing one. Others say it keeps people from spreading germs.

Lately, this silly graph has been bouncing around the internet:


Let's take some lessons from dietary science and apply them here.

Correlation isn't Causation 

One wag put up a graph that said, instead of Masks and No masks, Bubble Tea and No Bubble Tea. That must be it--let's all drink bubble tea!

Fun with Y Axes

Note the Y axis is cumulative cases, not cases per million population. Singapore and Hong Kong are city-states with populations of 5.8 million and 7.5 million. Those are small populations as far as countries go, so we'd expected them to have low cumulative numbers of cases.

Also note that these are cases, not deaths. Spain and Germany are in almost the same place on the chart, and yet Spain's deaths per million from COVID-19 are more than 20 times that of Germany at this writing. Most cases have mild or no symptoms--and nobody really knows how many cases there are.

Confounding Variables

Hong Kong suspended border crossings around early February. 
Singapore and Hong Kong are both the tropics, where COVID-19 hasn't been as common.
These are more reasons we'd expect them to have low numbers.

Does this Association Hold Up Elsewhere?

If mask wearing by the general public were effective in preventing COVID-10, we'd expect to see lower mortality rates from the regular flu in mask-wearing countries circled on the graph above, since the flu is spread the same way COVID19 is according to the CDC:
People with flu can spread it to others up to about 6 feet away. Most experts think that flu viruses spread mainly by droplets made when people with flu cough, sneeze or talk. These droplets can land in the mouths or noses of people who are nearby or possibly be inhaled into the lungs. Less often, a person might get flu by touching a surface or object that has flu virus on it and then touching their own mouth, nose, or possibly their eyes. [emphasis added]
But according to a study in the Lancet, flu mortality rates are all over the place. The figure is "Influenza lower respiratory tract infection mortality rate per 100 000 for all ages, 2017."


Deaths per 100,000 from flu lower respiratory tract infection:

Asia Pacific (High Income) 4.0

Japan: 5.1
South Korea: 1.6
Singapore: 3.0

China: 0.8

North America (High Income) 1.1

US: 1.1
Canada: 0.8

Western Europe: 2.1

Spain: 1.6
UK: 3.7
Italy: 0.8
Germany: 1.7
France: 2.2

I've added a few selected countries that are part of the averages for the regions. China's low figure of 0.8 seems low, considering it's typically the source of the flu. The rest of the figures are higher than the US and Canada. Those countries have an advantage of being mostly uncrowded. But there's no pattern within the group of mask-wearing countries--the range is 1.6 to 5.1 and whatever the figure for China really is. Which leads me to the last point.

Masks don't seem to be containing the flu in China. 

Conclusion

To be fair, the flu associations above aren't causal and probably have their own confounding variables. It may be that wearing a mask does help someone in the general population, but nothing here shows it.

If you're taking care of someone with COVID19, you should wear a mask. If you might be sick and can't avoid going out, or you have to be in an area where you can't avoid coughing or sneezing on others, then wear a mask. Find out how to wear it correctly. Or make your own and wear it if you like. But so far, I'm not convinced the general public, especially those of us still at the office who'd have to wear a mask all day, every day, for it to do any good, need to wear one.
Labels:

Comments

Post a Comment

Popular posts from this blog

My Long-Term Experience Eating Safe (and Other) Starches

Years ago, before the Perfect Health Diet came out, I followed a program that involved eating quite a bit "safe starch." It was called Body for Life. It involved eating six small servings of carbohydrate along with six small servings of protein, plus two servings of fibrous vegetables per day. (A serving was the size of your fist or the palm of your hand.) There were six workouts a week (three weightlifting, three cardio) and one free day every week where you ate whatever you wanted and didn't exercise. In all fairness, these two programs are different: BFL allows certain grains, legumes and low-fat dairy and discourages fat. It doesn't call for a wheelbarrow full of vegetation. Nevertheless, my experience eating lots of fruit and lots of starch is relevant to the PHD because the amount and type of digestible carbohydrates are similar, and for the first few years, I didn't eat wheat except on free days. At first on BFL, I felt great. Before, I was continually...
17 comments
Read more

Blog Lineup Change

Bye-bye, Fathead. I've enjoyed the blog, but can't endorse the high-fat, high-carb Perfect Health Diet that somehow makes so much sense to some otherwise bright people. An astrophysicist makes some rookie mistakes on a LC diet, misdiagnoses them, makes up "glucose deficiency," and creates a diet that's been shown in intervention studies to increase small LDL, which can lead to heart disease. A computer programmer believes in the diet and doesn't seem eager to refute it because, perhaps, scientists are freakin' liars and while he's good at spotting logical inconsistencies, lacks some intermediate knowledge of human biology. To Tom's credit, he says it's not the right diet for everyone, but given the truckload of food that has to be prepared and eaten, impracticality of following it while traveling (or even not traveling), and unsuitability for FODMAPs sufferers, diabetics and anyone prone to heart disease (i.e., much of the population), I'm...
24 comments
Read more

Carrageenan: A Sickening Thickener. Is it a Migraine Menace?

Let me tell you about my ride in an ambulance last night. I woke up at six o'clock from a nap with a mild headache. I ate dinner and took my vitamins, along with a couple of extra magnesium pills. Since magnesium helps my TMJ flare-ups, I thought it might help my headache. Then I went to see my mother. A few hours later, I had a severe headache, sinus pain and nausea. During a brief respite from the pain, I left for home, but less than a mile later, I got out of my car and threw up. A cop, Officer Fisher, pulled up behind me and asked if I was okay. He believed me when he said I hadn't been drinking, but he said I seemed lethargic and he wanted the paramedics to see me. (Later he mentioned that a man he'd recently stopped was having a stroke.) Thinking I had a migraine headache, the paramedics wanted to take me to the hospital. But since I knew that doctors don't know what causes migraine headaches, and I didn't know what effect their medicine would have on m...
15 comments
Read more