What do we know about the delta variant?

New information from the CDC and Benton County Health Department:


  • The Delta variant, which is a mutation of SARS-CoV-2, has become the dominant strain in Oregon – estimated to account for 80-90% of recent COVID-19 cases.
  • Recent COVID-19 cases have been found to be much as 3X more transmissible than earlier COVID-19 variants.
  • Delta is causing some “breakthrough infections,” meaning infections in fully vaccinated people. However, data also indicate that breakthrough infections in fully vaccinated people are milder.
  • Vaccination remains the most important tool in reducing the spread of COVID-19. If you are vaccinated, your risk of infection is around 3.5 times lower, your risk of getting ill from COVID is over 8 times lower, and your risk of hospitalization or death is around 25 times lower.
  • Data continue to demonstrate that the vaccines currently in use are effective against the Delta variant and are preventing severe illness, hospitalization and death. While no vaccine is 100% effective, vaccination is the best way to protect you, your family and your community.
  • Indoor masking is a simple way to help reduce the spread of the delta variant.
Last Modified: 
August 5, 2021