因为新冠肺炎能如此之快地传播给众人，所以几乎不可能通过电话追踪到所有接触过的人。

Because COVID-19 spreads so quickly to so many people, it's almost impossible to trace all contacts with phone calls.

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总之，我们无法下结论说电话追踪是一个有效的介入方法。

In summary, we cannot conclude that TFU is an effective intervention.

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然而，目前还不清楚电话追踪是否也可以减少出院后在居家照护的问题。

However, at present it is not clear whether TFU is also effective in reducing postdischarge problems.

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