According to a prevalence study led by Imperial College London, the spread of the Delta coronavirus variant fueled a 50% spike in infections in England since May.

The latest round of the prevalence survey, REACT-1, which was carried out from May 20 through June 7, noted the prevalence to be 0.15%, compared to 0.10% noted in the last round of data obtained between late April and early May. Steven Riley, professor of infectious disease dynamics at Imperial College London, said that prevalence is increasing rapidly and is doubling every 11 days. 

The study included 109,000 volunteers in the latest round… (Reuters, June 17, 2021)