https://www.bbc.co.uk/news/world-us-canada-54396670

I remember they kept on saying Boris Johnson was in "good spirits" right up until they were wheeling him into intensive care, but Trump looks the same as normal in that video, so, on that evidence, as I'm a naive soul and therefore give no credence to conspiracy theories about him not really having the virus, I'd say it's all precautionary.