Experts warn of more COVID-19 variants after Omicron

• The chance of the virus mutating increases with every infection, raising concerns as the highly contagious Omicron variant rapidly spreads, per AP.

Between the lines: It's not clear what subsequent variants might look like or how they may impact the pandemic, experts caution.

What they're saying: "The faster Omicron spreads, the more opportunities there are for mutation, potentially leading to more variants," Leonardo Martinez, an infectious disease epidemiologist at Boston University, told AP.

• "It’s the longer, persistent infections that seem to be the most likely breeding grounds for new variants," Stuart Campbell Ray, an infectious disease expert at Johns Hopkins University, said, per AP.
• "It’s only when you have very widespread infection that you’re going to provide the opportunity for that to occur."

The big picture: Preliminary research suggests that the highly contagious Omicron variant is more resistant to prior coronavirus infection than with other variants, Axios' Caitlin Owens reports.

• Initial studies also have found that coronavirus vaccines — particularly without a booster shot — are less effective against Omicron infections than other variants, although they appear to hold up well against severe disease.
• The World Health Organization reported nearly 20 million new COVID-19 cases over the last seven days.

Go deeper: Protection from prior infection significantly reduced against Omicron