As many countries start to expand isolation and tracing efforts, it's worth highlighting a couple of important aspects of the response in places like Taiwan, Korea and Hong Kong: surveillance infrastructure and strict enforcement. 1/
In Korea, centralised phone location tracking has been used to identify contacts (wwwnc.cdc.gov/eid/article/26…) and to enforce quarantine (undp.org/content/seoul_…) 2/ 
In Taiwan, an 'electronic fence' ensures people stay in quarantine
(bbc.co.uk/news/technolog…) and in Hong Kong, at-risk contacts received rapid, mandatory quarantine orders (thetimes.co.uk/article/the-ne…) 3/
(bbc.co.uk/news/technolog…) and in Hong Kong, at-risk contacts received rapid, mandatory quarantine orders (thetimes.co.uk/article/the-ne…) 3/
From a purely public health point of view, giving outbreak investigators access to detailed data on suspected cases makes it less likely that infections will be missed - it's much easier to track contacts and keep them in quarantine if you know their location and test status. 4/
Of course, there are privacy implications for such surveillance, which is why groups are now looking at privacy-protecting apps, which reduce the data shared with health authorities.... nytimes.com/2020/04/29/bus… 5/
But to be most effective, such apps require high (voluntary?) uptake from populations and strict adherence when people are told to get tested/quarantine. As a result, they will likely only form one (possibly quite small) part of the ongoing response cmmid.github.io/topics/covid19… 6/
There is a much wider discussion to be had about what will/won't be feasible, and what privacy trade off is/isn't acceptable. But when we talk about reproducing control strategies from other countries, it's important to consider all aspects of that strategy. 7/7
