How can Covid-19 contact tracing work?
 

I saw in the news that 3 TSA employees at SJC have been confirmed with Covid-19: https://www.mercurynews.com/2020/03/...-for-covid-19/ :In small places like Singapore and Taiwan, the governments spend a lot of time tracking down contacts for confirmed cases. For example, Taiwan tracked down 419 people for a visiting musician from Australia who probably caught this in Europe (and was not confirmed until he returned to AU: ).

How would this work in the US - it is so big, people move all over, government is decentralized, no money, etc...

It is harder and doesn’t work as well, as you suggested. They take friends, family, coworker and quarantine them. But they might miss some spas you suggest.

At my employer here in Brussels/Belgium, we're asked to keep a log of everyone we're meeting (even if they're colleagues from other departments). It's a bit burdensome, but if there were to be a case, it would be very easy to trace.

so, in a way, they are asking you to trace yourself. It's an honor system., i.e. they wouldn't know if you lied.

Well, it's not a tracing exercise at this stage. You keep a record and it is encoded by secretarial staff every day. So there is some control and social pressure to comply. Also, it's unlikely someone will start lying in advance of getting sick. But of course there may be errors and omissions. A watertight system would be way, way more burdensome - if at all possible - for a very marginal gain in risk reduction compared to what they put in place now (which, frankly, is already creating quite some overhead).

Seeing how many people using their phones' cellular functions to transmit during taxi, takeoff and landing, we have a big problem. In the US, you also have to worry about liabilities so how will people be honest?

The "downside" of not being able to use your phone is being disconnected, which many people hate, and they see no consequences to their disobedience of the rules.

There's very little downside (for the person being asked) to being honest when asked about contact tracing. And it will be stressed to them that it's for public health and they'll be helping prevent potential infections and so on, which may induce some guilt (i.e. negative consequence to not cooperating).

(Keep in mind that we're not talking about the person whose contacts are being traced, who may have had incentive to lie about their own condition to avoid quarantine etc; if a health authority is trying to trace their contacts, they've almost certainly already been diagnosed)

I wonder if any contact tracing is occurring in the US at all. With the huge numbers we have now, is this happening anywhere?

Have all cellphone carriers send text to ask customers to opt in to allow carriers to share their GPS and cell towers ping information to public health authorities for 30 days without court orders. The data will be deidentified, can only be used for contact tracing purpose and will be destroyed after 30 days.

This is only work contacts during working hours, right? Or are people expected to report the job interview during the lunch hour and/or the mistress after work?

Almost certainly. It's happening with every confirmed case in Canada. Contact tracing is one of the backbones of public health

With the huge numbers, how can they do this? It is a very labourious process to do this right.

If only this disease did not feature dominant asymptomatic transmission, mitigation via contact tracing and quarantine could be quite effective in the long run for large and dispersed populations.

In smaller countries or territories like Hong Kong and Singapore, this is probably easier to conduct. Or even when your infected caseload are in the low hundreds. When you start to have tens of thousands of cases, I fear this becomes too cumbersome and it is best to try and quarantine large sections of the population.

Singapore Ministry of Health uses some 1300 people with some from the Singapore Armed Forces.

But you have to start early, like when you have say 15 cases.

https://www.channelnewsasia.com/news...id-19-12606752