Unpublished research indicates that the Delta variant causes more severe illness and spreads as easily as chickenpox, and that vaccinated people may transmit the strain as easily as those who are unvaccinated, according to an internal CDC presentation obtained by WashPost.
Why it matters: The data played a key role in the CDC's decision to tell vaccinated people to resume masking indoors, with the presentation calling on health officials to "acknowledge the war has changed," The Post reports.
