Not quite true - we're down to around 14 days with the latest generation of tests.

The ideal would be a rapid 'fever' panel that tests for all the viruses we currently pay a ton of money for. This sort of test could pick up early-stage HIV which, if symptomatic, don't feel much different from a cold/flu.

[1] - https://www.aafp.org/afp/2014/0215/afp20140215p265-f1.gif