The highly transmissible Delta variant made up nearly all cases in Southern California by mid-summer, with some groups at higher risk of infection than others, a new report finds.
Researchers from the Centers for Disease Control and Prevention (CDC) found that the variant accounted for 95 percent of Covid cases that underwent genome sequencing at Kaiser Permanente Southern California (KPSC) as of July 21.
Hispanic Americans and adults under age 45 were the most likely to be confirmed to have Delta.
What's more, the report found that unvaccinated patients infected with Delta were almost twice as likely to be hospitalized as fully vaccinated patients who had breakthrough infections.
A new CDC report from Kaiser Permanente Southern California found that adults between ages 18 and 44 accounted for more than half of positive Delta specimens at 55.3%
Hispanics were the most likely race/ethnicity to be confirmed with Delta, accounting for 39.4% of all infections
Known as B.1.617.2, the Delta variant first originated in India and was labeled a 'double mutant' by the country's Health Ministry because it carries two mutations: L452R and E484Q.
L452R is the same mutation seen with the California homegrown variant and E484Q is similar to the mutation seen with the Beta and Gamma variants.
Both of the mutations occur on key parts of the virus that allows it to enter and infect human cells.
The Delta variant is twice as contagious as previous variants, and some studies have suggested it can cause more severe illness in unvaccinated people compared to earlier strains.
The CDC says that Delta and its sub-lineages are currently responsible for 99.5 percent of all new infections in the U.S.
However, there is little research detailing the demographic breakdown of those infected by variant, including Delta.
For the new report, published on Thursday, the team looked at data from patients at KPSC.
Researchers sequenced data from 6,798 specimens positive
