Study of 780,225 US veterans and vaccinations:
https://www.science.org/doi/10.1126/science.abm0620
When Delta came, both vaccinated and unvaccinated veterans had a more difficult time escaping infection:
“Kaplan-Meier curves illustrating cumulative risk of SARS-CoV-2 infection by vaccination status and age. (A) All ages. (B) Age <50 years. (C) Age 50-64 years. (D) Age ≥65 years. The survival function estimates time to infection detected by most recent RT-PCR assay.”
However, vaccinated veterans were much less likely to die:
“Kaplan-Meier curves illustrating cumulative risk of death due to any cause by vaccination status and RT-PCR assay. (A) Age <65 years. (B) Age ≥65 years. (C) Charlson Comorbidity Index score <3. (D) Charlson Comorbidity Index score ≥3.”