...note that it includes a clip of CDC Director, Dr. Rochelle Walensky making the exact statement Rachel repeated...i.e. Rachel was repeating what she had learned from the CDC. Go back and read my entire post and link...it explains why it was Dr. Walensky's error to overstate the effectiveness of the COVID vaccines (but not by much)...NOT RACHEL MADDOW.
I'm not blaming you for your claim...you've been misinformed by your news source(s)...for some reason they left out the initial portion of the broadcast where the CDC's Director made the statement that Rachel simply repeated...and why not, when it's someone of that stature.
Link: https://www.msnbc.com/transcripts/transcript-rachel-maddow-show-3-29-21-n1262442