SACRAMENTO, Calif. (KTXL) — The Center for Disease Control’s transmission map shows COVID-19 activity is increasing across California.

The federal agency reports more than 98% of state residents live in areas where COVID-19 activity is high.

According to health officials, Omicron subvariant BA.5 is the main cause of the virus’s increased activity.

The CDC says out of the 58 California counties, 50 have a high covid transmission level, equating to nearly 39 million Californians. The only counties with a lower risk are: Alpine, Glenn, Humboldt, Mendocino, Mono, Santa Cruz, Sierra, and Siskiyou.

Health officials recommend people wear masks while indoors.

“We know that Ba.5 is the current dominant variant and the reason why we worry about Ba.5, it is very infectious and two, it can cause reinfection and as well as invade immunity in people who are fully vaccinated or boosted,” said Dr. Aimee Sisson.

Yolo County is one of the counties that categorize in the high risk group. Dr. Sisson says their case rate numbers might not show the entire picture since they closed their largest testing facility.

“As a result, our case rate has fallen, and we know that is misleading because when we look at wastewater levels are still high and, in many cases, still climbing,” she explained.

Dr. Sisson also says the vaccine is still effective in keeping people out of the hospital.

The California Department of Public Health shows new case rates stand at 45.6 per 100,000 across the Sacramento region.

Dr. Greg Poland with Mayo Clinic says he doesn’t think people are taking enough precautions. He also says people should be worried about catching it multiple times.

“Regardless of how mild they are you are adding and adding and adding onto your risks,” he said. “We’re playing with fire here; we’re pretending the pandemic is over.”

Health officials warn people should think about what kind of masks they use.

“Ba.5 laughs at a surgical mask or a cloth mask. We really want people to wear a higher quality mask… as N95, Kn95 or KF94,” she explained.

Dr. Sisson also adds that even vaccinated people can catch the new variant, the vaccine is still the strongest defense.

“If you are over the age of 50 or has somebody in your life who is over the age of 50, please don’t wait to get the second booster. Covid rates are very high right now, so now is the best time to get that second booster,” she said.

Anyone six months and older is eligible to get a COVID-19 vaccine. People 5 years old and older are eligible for a booster shot.

For more information on the CDC’s California transmission data you can visit it’s official website.