CDC: “What is already known about this topic? The incidence of SARS-CoV-2 infection, hospitalization, and death is higher in unvaccinated than vaccinated persons, and the incidence rate ratios are related to vaccine effectiveness. What is added by this report? Across 13 U.S. jurisdictions, incidence rate ratios for hospitalization and death changed relatively little after the SARS-CoV-2 B.1.617.2 (Delta) variant reached predominance, suggesting high, continued vaccine effectiveness against severe COVID-19. Case IRRs decreased, suggesting reduced vaccine effectiveness for prevention of SARS-CoV-2 infections. What are the implications for public health practice? Getting vaccinated protects against severe illness from COVID-19, including the Delta variant. Monitoring COVID-19 incidence by vaccination status might provide early signals of potential changes in vaccine effectiveness that can be confirmed through robust controlled studies…”

See also NPR – I Got A ‘Mild’ Breakthrough Case. Here’s What I Wish I’d Known – “…Not only was I sick, but I’d brought the virus home and exposed my 67-year-old father and extended family during my very first trip back to the East Coast since the start of the pandemic. It was just the scenario I had tried to avoid for a year and a half. And it definitely was not the summer vacation I had anticipated. Where did I get it? Who knows. Like so many Americans, I had loosened up with wearing masks and social distancing, after getting fully vaccinated. We had flown across the country, seen friends, stayed at a hotel, eaten indoors and, yes, even went to a long delayed wedding with other vaccinated people…”