Philadelphia cautiously braces for new Omicron variant

The Omicron variant hasn't yet been detected in Philadelphia, but the city is bracing for the inevitable.

Driving the news: The first U.S. case of the new coronavirus variant was reported in California on Wednesday.

• E. John Wherry, an immunologist at the University of Pennsylvania's Perelman School of Medicine, expects Omicron to turn up in Philadelphia and other major cities within a week.

State of play: COVID-19 cases are on the rise in Philly — with a 5% positivity rate as of Wednesday, up from 3% two weeks ago. But it's still a far cry compared to this time last December, when the city had a 11.7% positivity rate.

• Philadelphia Health Commissioner Cheryl Bettigole said the city isn't issuing any new COVID restrictions at this time, opting to continue pushing vaccine mandates and mask-wearing.
• Yes, but: Bettigole warned, "I can't promise that will continue to be the case. We don't know what's coming with Omicron."

What they're saying: The Omicron variant appears to be more transmissible compared to the Delta variant, Bettigole said.

• It's unknown how the new variant affects people who are vaccinated, but she expects some decrease in efficacy. Bettigole said the current vaccines could be 80-85% effective or lower.
• Bettigole advises anyone who is not vaccinated or hasn’t had their booster to avoid gathering indoors.

Meanwhile, Wherry said Omicron could lead to an increase in infections, including among the vaccinated population, due to the variant's high number of mutations, but it remains to be seen whether hospitalizations would also rise.

• "With more mutations, it's going to be more evasive. It's going to get around our antibodies even better," he said.

What's next: Bettigole said she wants to build a sequencing unit within the city's public health lab.

• Currently, the city works with both the Children's Hospital of Philadelphia and University of Pennsylvania, which conduct the main sequencing.