The CDC is reporting that vaccinated individuals may be as likely to transmit the Delta variant as unvaccinated people, although vaccination continues to provide the protection of reduced covid-19 symptoms.
The Washington Post has the CDC presentation available here in this article:
Read: Internal CDC document on breakthrough infections (2021, July 30): https://www.washingtonpost.com/context/cdc-breakthrough-infections/94390e3a-5e45-44a5-ac40-2744e4e25f2e/