The SARS-CoV-2 Delta variant might cause high viral loads, is highly transmissible, and contains
mutations that confer partial immune escape 1,2. Outbreak investigations suggest that vaccinated
persons can spread Delta 3,4. We compared RT-PCR cycle threshold (Ct) data from 699 swab
specimens collected in Wisconsin 29 June through 31 July 2021 and tested with a qualitative assay by
a single contract laboratory. Specimens came from residents of 36 counties, most in southern and
southeastern Wisconsin, and 81% of cases were not associated with an outbreak. During this time,
estimated prevalence of Delta variants in Wisconsin increased from 69% to over 95%. Vaccination
status was determined via self-reporting and state immunization records
2Medical.News 