Omicron appears to cause mild illness, but experts say too early to know for sure

Compared with other variants, Omicron "looks less severe in really early data."

Since the first case of the new Omicron variant was detected last month, early anecdotal reports indicate people infected seem to be experiencing mild illness -- leading some scientists to wonder if this version of the virus could be less dangerous than prior variants.

But scientists have cautioned it's too soon to know for sure.

It "looks less severe in really early data," Centers for Disease Control and Prevention Director Dr. Rochelle Walensky told ABC News Chief Medical Correspondent Dr. Jennifer Ashton in an interview from CDC headquarters in Atlanta. "We're certainly following and very interested in disease severity."

Omicron was dubbed a "variant of concern" due to its many mutations. As a result, scientists are scrambling to determine if these changes lead to increased transmissibility or weakened response from vaccines. The World Health Organization said several studies are underway and that more information will emerge in the following days to weeks. Preliminary studies show that the Pfizer vaccine may be less effective against the Omicron variant, but, again, more research is needed.