You are cutting important parts of the statement, the individual was not in the office after showing symptoms and current research shows that it is very unlikely to transmit the virus before showing symptoms.
https://www.cdc.gov/coronavirus/2019-ncov/about/transmission...
It's worth noting that this document does not make any claim that it cannot spread prior to symptoms. It says this:
" - People are thought to be most contagious when they are most symptomatic (the sickest). - Some spread might be possible before people show symptoms; there have been reports of this occurring with this new coronavirus, but this is not thought to be the main way the virus spreads."