Centers for Disease Control and Prevention

CDC level of COVID-19 community transmission by state, as of July 12, 2021

Health officials continue to urge caution as the delta variant of COVID-19 spreads in Arizona. Delta is thought to be the most transmissible strain of the virus yet.

Medical experts say the best protection against the delta variant is to get fully vaccinated. About 44% of Arizonans are now fully immunized — that’s below the national average. As the extremely infectious delta variant spreads, areas of the country with lower vaccination rates are now tending to see higher caseloads. The Centers for Disease Control and Prevention now classifies Arizona’s level of COVID-19 community transmission as “substantial” while most of the country remains at the “moderate” level. 

Because a portion of the state's population is inoculated, Dr. Rebecca Sunenshine with Maricopa County Public Health said it's unlikely Arizona will see a new surge in cases as severe as previous outbreaks. But she said most Arizonans are still vulnerable to infection. 

“This particular virus strain is much more contagious and it can be more severe in young people, so we really don’t know what it’s going to look like," Sunenshine said. 

Sunenshine pointed out older Arizonans are vaccinated in the highest numbers. She said the state's younger population is most at risk. 

“That 20-to-44 age group, is not very well vaccinated," Sunenshine said. "If they had more severe disease, we could definitely overwhelm our health care system.”

About 20% of recent COVID-19 cases in the state have been caused by the delta variant. Sunenshine said she expects that number to continue to grow.

"It's really a race to get as many people vaccinated before the delta strain becomes the dominant one in Maricopa County," she said.