BA.5, the newest COVID subvariant of the omicron family, comes with a new problem.
Not only is it more contagious, but early research shows it appears to be both vaccine and immunity resistant, meaning those who have had COVID before - even recently - are not protected, health officials said.
"I think we're heading into a period of frustration, a period of uncertainty," UCSF infectious disease specialist Dr. Peter Chin-Hong said. "If you've had omicron recently, you're not going to get that out of jail pass as much as you would have liked, unfortunately."
Get a weekly recap of the latest San Francisco Bay Area housing news. Sign up for NBC Bay Area’s Housing Deconstructed newsletter.
And while the number of COVID cases has plateaued in recent weeks, the overall number of cases remain incredibly high.
Chin-Hong said it is more important than ever to protect yourself, especially if you're over 50 years old. He adds the BA.5 is also more likely than earlier variants to be transmissible outdoors through close contact.
Chin-Hong said outside visits are still much safer, but consider keeping a little extra distance.