Anyone who is infected is hospitalised, which helps to enforce isolation, while contacts are isolated at home with the immediate neighbourhood placed under a local lockdown.
BY JIMMY WHITWORTH
There has been clear communication and the issue is seen as non-political and a matter of public health.
South Korea, meanwhile, has used retrospective contact tracing to investigate outbreaks and understand where transmission is occurring. As a result many bars, night clubs, karaoke bars and places of worship have been closed.
Taiwan, where there have been no reported deaths since May, has probably the most effective testing and tracing programme. Cases are followed up twice daily by telephone, text messages or home visits to reinforce the self-isolation message, and to offer support, which can include meal and grocery delivery. Contact tracing is highly effective, identifying on average 20-30 contacts per case.
Crucially, contact tracing only works if it is done properly. The World Health Organisation stresses the importance of not just identifying cases, but following them up and giving support. They estimate that on average each case needs three days of work from the testing and tracing team.
Clearly, this can only be feasible if the number of daily cases is brought down to manageable levels, which is not the case in many European countries, nor in parts of the US.
Unfortunately, with case numbers as high as they are in these places, the best approach for Western countries getting through the winter seems to be to continue to use national or local lockdowns. But these should be combined with new tools, including mass testing, to bring down the number of new infections so that effective case detection and contact tracing with local follow-up and support can control continuing chains of transmission.
Of course, the success of all these measures will depend on understanding, trust and participation from all population groups.
This piece has been updated to correct an error that was introduced in the editing process relating to the positivity and negativity rates of COVID-19 tests in Liverpool.