Update on vaccination and the Delta variant

As with any hot field, the question of how the Delta variant interacts with the vaccine is fraught with conflicting evidence. One concern I have, not mentioned in the link below, is that the PCR test cannot distinguish between infectious virus particles and RNA remnants from damaged/destroyed virus. Therefore, what is being measured isn't necessarily viral burden or the ability to infect others.

Probably the best data is described at the end (h/t Nature):

"One massive analysis of Delta transmission comes from the UK REACT-1 programme, led by a team at Imperial College London, which tests more than 100,000 UK volunteers every few weeks. The team ran Ct analyses for samples received in May, June and July, when Delta was rapidly replacing other variants to become the dominant driver of COVID-19 in the country. The results suggested that among people testing positive, those who had been vaccinated had a lower viral load on average than did unvaccinated people. Paul Elliott, an epidemiologist at Imperial, says that these results differ from other Ct studies because this study sampled the population at random and included people who tested positive without showing symptoms."

https://www.nature.com/articles/d41586-021-02187-1?WT.ec_id=NATURE-20210819&utm_source=nature_etoc&utm_medium=email&utm_campaign=20210819&sap-outbound-id=227918FE6CD5D1A0989907FF61E07EA02C0C6636