Give everyone LCT strips

The idea previously of LCT bracelets won't work. Arm temperatures are just not accurate enough to show fever. In some cases when you get a fever your lower limbs actually gets colder.

But that does not mean these cheap thermometers are of no benefit. There is an interesting model here from Paul Romer about how even an inaccurate test can reduce spread. Here is his simulation for a test with a 20% and 40% false negative rate results in large reductions in the spike int he number of infections.

and with 40% False Negative Rate

One such test might be the thermometer test for fever it is cheap but not very accurate. About 30% of people might not have fevers in spite of having covid-19.  It seems to be unknown how infections these asymptomatic people are.

Another paper on Wuhan says "Per person, these undocumented infections were half (52 percent) as contagious as documented infections yet were the source of two-thirds of documented infections" but undocumented does not mean asymptomatic.

There is also this interesting article on the issues with temperature checking in Asia. ‘Thermometer Guns’ on Coronavirus Front Lines Are ‘Notoriously Not Accurate’ it seems outdoor ones are pretty useless. And they need to be aimed very carefully.

All these bits of evidence combined seem to suggest that encouraging and facilitating everyone to check their temperature everyday at home might be worthwhile. LCT strips in particular are still available and are really cheap. 

Here is a supplier that can provide a million reusable LCT a month at a price of 3.6 cent each. There are 1.7 million dwellings in Ireland. Buying one for every dwelling in Ireland would cost 62,500 euro. 138.45 million housing units in the United States = 6 million dollars

Supplying these to households as a cheap if not very accurate test could well meet a cost benefit analysis.

Automatic Temperature Scanning 2

Here is a design to find fever in streams of people entering a workplace, school or public building

This can be done by hand but I want to make it cheaper

Ultrasonic detector tells someone is in front of it. (MLX90614)
Gets them to the right distance with a display (not shown)
Mirrored picture in an antiviral metal helps the person line themselves up in front of the IR sensor.
Flashes red if they are above 37.5C

Temperature Measuring Bracelet

If it is a good idea to check peoples temperatures a lot there are probably three distances you want to check them at

1. Personal level

2. Places lots of people go through like employee bathrooms

3. Public places like airports.

Each of these has different requirements.

For Personal thermometers the idea is you have a temperature sensor showing you do not currently have a fever. And if you do that is rapidly detected to reduce the number of people you infect. 

Personal thermometers they need to be really cheap. Not need much power. And be socially fashionable to show off.

Liquid crystal thermometer fits most of these requirements. These were suggested by Tara Whelan

Can they be made durable enough and fashionable enough to get people to wear them?

Earlier posts: Why temperature checking would help . 

Edit: the physiology of the arm means these won't work as bracelets.

Automatic Temperature Scanning

I blogged last night about how automatic temperature reading of people several times a day might reduce the number of infectious people out in public

Temperature Scanners Everywhere  Is that post if you want to see the reasoning. 

How about we put a remote thermometer and displays on bathroom mirrors?

What would happen if you 

1. Attached Infrared thermometers (slightly reassembled) to the mirror

2. Put a switch on it that turned it on when someone stood in front of the mirror

3. Output the reading to a display on the mirror

There are several instructable here on how to make the handheld type of forehead thermometer at a distance https://www.instructables.com/id/Arduino-Laser-Infrared-Thermometer/ this is much the same mechanism but in a different container.

All these parts combined and mass produced would probably cost around 10 Euro. Private and Employee bathrooms might be best for privacy reasons. There is no network connection or face recognition involved here just a very simple temperature reading.

Temperature Scanners Everywhere

'Why did Singapore’s containment strategy work, in such a high-density location?  Their program is mostly symptom/temperature checking-based'

It does seem like having symptoms really ups how infectious you are
"while we are learning that there are people who can shed COVID-19 virus 24-48 hours prior to symptom onset, at present, this does not appear to be a major driver of transmission. " WHO

'Some spread might be possible before people show symptoms; there have been reports of this occurring with this new coronavirus, but this is not thought to be the main way the virus spreads. ' CDC

Singapore is doing twice a day checks for some people
'All employers should require their employees to check their temperature at least twice daily, check for respiratory symptoms, and for those unwell to visit a doctor immediately.' During SARS they did something similar 'Singapore became the so-called country of thermometers: temperature monitoring was made mandatory in schools and temperature screening was instituted at entry to public buildings.'

In China 'In every business I enter (whether that’s a restaurant, supermarket, or retailer), someone takes my temperature and asks me to write down my phone number. Taikooli, the large outdoor mall by where I live, has blocked off most entrances to corral people into temperature check zones'

Airport screening does not work as it only catches you if you are sick at just the right moment so the checks have to be regular.

 What is the most efficient way to get peoples temperatures checked twice a day? Non-Contact Infrared Thermometer are cheap ($10). Paying people to hold them is expensive. Grabbing a thermometer others have grabbed sounds unhygienic. And trusting people to measure themselves expects a lot from them. But a thermometer held on a stand that checked people, that's cheap. Some logging would probably be necessary but lets work out the basic concept first.

Would twice daily temperature checks reduce R0? The idea is to reduce the period of time someone with symptoms is not isolated.
If so is there a way to set up a machine to check your temperature so they do not have to be manual?

Corona Virus and the Wheat on Chessboard problem

Exponential growth is really counter intuitive. But think of a chessboard where on the first square you have one grain of wheat. And every square you double the amount of wheat

Entire World Population number of wheat is square 34.

UK and Italy population are each square 27

US is Square 29

Ireland is square 24

Cases of Coronavirus currently UK, US and Ireland are about 18 squares behind the entire population number. Italy about 13 squares behind. Or 5 ahead of us. We at the moment move onto a new square every 4 days according to here. So Italy now is Ireland, UK or US in three weeks time at that really fast growth rate. Infection rates are not exactly exponential, eventually they start running out of new people to infect. But thinking about doubling is a useful shorthand to see how things can get scary fast.

I work with colleagues in China. The region they are in Liaoning has 43 million people. This would be Square 26.5. Liaoning, Mainland China
Confirmed: 125 Deaths: 1 Recovered: 110 Active: 14 These 125 cases puts them on square 8. They are at the same ratio as we are 18 doublings behind everyone being infected.

They wear mask all the time outside and in the office. Each person is only allowed to go to office one day in 3. All schools are closed.

They are at the same point as Ireland, UK and US and are on lockdown compared to here. Increasing this time to move to the next square like China and Singapore have done is really important