Delta changed everything except Government's briefing

The NHS message about double vaccinated people transmitting the virus is struggling in the face of Government's briefing still being driven by old data on previous variants. The more virulent Delta variant has over 1,000 times higher viral load than previous variants and unfortunately previous transmission benefits no longer apply. This is because the peak viral load is the same, see the graph, and the viral load the same throughout the first 11 days post infection see the graph, which completely covers the maximum circulatory transmission, irrespective of asymptomatic or symptomatic disease and irrespective of vaccination status. On average, after 11 days post infection, people are either recovering and the virus which they shed is no longer infectious (Ct level of 30 and above), or are sick in bed and not circulating, and certainly not treating patients.

Reference.  Virological and serological kinetics of SARS-CoV-2 Delta variant vaccine-breakthrough infections: a multi-center cohort study.  Po Ying Chia, Sean Wei Xiang Ong, et al. medRxiv 2021.07.28.21261295; doi: https://doi.org/10.1101/2021.07.28.21261295