CDC says vaccinated people can spread delta

The CDC conducted a study on a COVID-19 outbreak in Massachusetts, revealing that vaccinated individuals infected with the Delta variant have similar viral loads to unvaccinated people, influencing mask-wearing guidelines. A Chinese study found Delta patients have significantly higher viral loads and shorter incubation periods. A CDC report indicates Delta is more transmissible and causes more severe illness, but vaccines remain effective in preventing serious disease.

What change did the CDC make regarding mask-wearing for vaccinated individuals?

According to the CDC report, how much more transmissible is Delta compared to the original COVID variant?