I’m seeing some fatalism creep in around whether contact tracing system/app will work. But remember, most the reduction in transmission is likely to come from the first step - when you promptly self-isolate and get tested as soon you have symptoms (and household isolate too)...1/

We estimated that this initial step alone could lead to 30-35% reduction in transmission - effective tracing can then lead to further reduction on top of this (allowing some physical distancing measures to be relaxed). https://cmmid.github.io/topics/covid19/tracing-bbc.html 2/

The guidelines also encourage you to do some DIY tracing alongside the formal system - let others know that you’re ill, so they can be extra careful about distancing while you wait for your test result. https://www.nhs.uk/conditions/coronavirus-covid-19/what-to-do-if-you-or-someone-you-live-with-has-coronavirus-symptoms/when-to-self-isolate-and-what-to-do/ 3/

We’re still in early stages of this pandemic. So even if you’re frustrated & sceptical about what’s happening with wider testing/tracing/isolation, do stick with the aspects of it that are in your control, because these things can make real difference in reducing transmission 4/4