For healthy individuals it was never dangerous. Noah should have just told everyone he had a cold. Same diff.
It sounds like the crud is going around in the village. He got sick, and it hurt his performance, but he gutted it out for third. That's it. That's the story.
Three years ago, we were still in a declared emergency. That declaration is no longer in place, and the pandemic is over. Just like the flu of 1917, COVID-19 is now basically just a cold. That being the case and there being no protocol for athletes to alert others to their issues (besides, here in the states that's private HIPPA info), I don't think Lyles had any reason nor responsibility to announce. This isn't 2020-21 anymore.