[myko]

https://www.cnn.com/2021/07/27/health/cdc-mask-guidance-vacc...

There are many more breakthrough cases with the delta variant. That said, the vaccines are still very good at combatting serious illness:

    We continue to estimate that the risk of a breakthrough 
    infection with symptom upon exposure to the Delta variant 
    is reduced by seven-fold. The reduction of 20-fold for 
    hospitalizations, and deaths," Walensky said during 
    Tuesday's briefing.