C.D.C. Internal Report Calls Delta Variant as Contagious as Chickenpox July 30, 2021 and lead more often to severe illness. +4 IFTTT Infections in vaccinated Americans also may be as transmissible as those in unvaccinated people NYT NYT > Business NYTimes the document says and lead more often to severe illness. IFTTT Infections in vaccinated Americans also may be as transmissible as those in unvaccinated people NYT NYT > Business NYTimes the document says