The hyper-transmissible delta variant is now the most common COVID-19 strain in California, according to the California Department of Public Health.
The health department says the delta variant now accounts for more than 35% of new COVID-19 cases in the state, up significantly from 5% of California's cases in May.
"What's surprising to me is not only that it's the most common, but the rate of increase is really dizzying," UCSF infectious disease expert Dr. Peter Chin-Hong said. "It's expected to be over 90% in a few months, if not in a few weeks."
Chin-Hong noted that there is also a possibility that the delta variant might also cause more severe symptoms.
"The fact that it produces more virus and people produce virus for a longer period of time, not only makes it more transmissible but potentially more deadly," he said.
Flamingo Nail Salon in Walnut Creek hasn't taken any chances since reopening in February. Even after the state lifted its mask mandate for vaccinated people last month, the salon decided masks would still be mandatory.
"We cannot check everybody, the vaccination card, so we don’t know who is vaccinated," manager Tiffany Nguyen said. "That's why we do that. That’s better."
But while some businesses are taking all precautions, others worry a second mask mandate could crush them.
"To be honest, at this point, I don’t know what to do," Brioche de Paris owner Sam Kheriji said.
Kheriji said he's taken too much of a hit during the pandemic and said his customers would not be OK with putting masks back on.
"There is not much I can do," Kheriji said.
In the meantime, people who haven't been vaccinated yet are encouraged to do so.
"It's really a good time to get vaccinated if you haven't because right now things are still pretty quiet in the Bay Area, but we don't know how long that quiet will last," Chin-Hong said.