PHOENIX — As the more contagious Delta variant spreads rapidly, health experts are worried vaccines won’t be as effective in preventing the spread of COVID-19.

The Delta variant spreads more easily and can lead to more severe illness.

ABC15 Health Insider Dr. Shad Marvasti and the director of Public Health and Prevention at the University of Arizona College of Medicine-Phoenix has been following several new studies on the Delta variant, including one from Israel this week that shows the Pfizer vaccine appears to be less effective against Delta infections. The study shows the vaccine provided 64% protection, compared to earlier studies before Delta that had the vaccine at 95% efficacy.

“You’re definitely much higher risk than you were before the Delta variant showed up,” said Dr. Shad.

But Dr. Shad said it’s too early to really know how effective vaccines are against the variant.

“The Delta variant is spreading so rapidly, it’s doubling every two weeks, that in about 6-8 weeks, not only will it be dominant variant in the United States and in and Arizona, but we’ll also have more data to see what percentage of fully vaccinated people actually get it, how sick can they get.”

Dr. Shad said in the meantime, even vaccinated people should be taking precautions.

“It’s quite reasonable, especially in indoor crowded spaces, even for vaccinated people to wear a mask because the risk of getting sick is higher now than it ever has been before for people who are fully vaccinated,” he said.

According to the Arizona Department of Health Services, data through July 7 shows there have been 2,922 vaccine breakthrough cases identified in all 15 counties. That’s out of nearly 3.2 million fully vaccinated people in Arizona.

AZDHS said of those reached for case investigation, 80% were symptomatic and 17% were hospitalized, though it isn’t known whether the hospitalization related directly to COVID-19.

There have been 25 deaths among the breakthrough cases.

This interactive graphic shows the breakthrough COVID-19 cases in those that are fully vaccinated in Arizona. To use it, simply press on each circle and drill down to the next level. When choosing breakthrough, you will see the number of people who were symptomatic, went to the hospital, and the ultimate outcome of the case.

A spokesperson from AZDHS said “all of the available COVID-19 vaccines are effective at preventing severe illness, hospitalizations, and deaths. As a result, symptomatic vaccine breakthrough cases will tend to be less severe than infections in people who are not vaccinated. Asymptomatic infections among vaccinated people also will occur.”

“The only question that is out there is whether or not that percentage is going to increase because of Delta,” said Dr. Shad.

The question also remains–how sick could you get from the Delta variant if you’re fully vaccinated?

Dr. Shad said one thing is clear—vaccines are effective in preventing severe illness, hospitalizations and deaths.

“You’re much better off being vaccinated than not vaccinated now more than ever,” he said.

Dr. Shad had some advice, even for those who are vaccinated:

*Limit activities to smaller groups who are fully vaccinated
*Wear a mask in larger, indoor group settings
*Take care of yourself by eating healthy, exercising, getting enough sleep and hydrating.