Omicron updates: COVID-19 cases could double in New York City

Dr. Anthony Fauci on Tuesday told news agency Agence France-Presse that the omicron variant is "almost certainly" not more severe than delta.

He stressed, however, that it is important to not overinterpret early data, as the patients being followed skew younger and are less likely to become hospitalized. Severe illness can take weeks to develop.

"There is some suggestion that it might even be less severe, because when you look at some of the cohorts that are being followed in South Africa, the ratio between the number of infections and the number of hospitalizations seems to be less than with delta," Fauci said.

He also reiterated that it would take at least several more weeks to understand key questions surrounding omicron's severity.

Results from labs testing current vaccines against omicron should come in the "next few days to a week," Fauci said.

-ABC News' Arielle Mitropoulos

The daily death average in the U.S. has increased to more than 1,150 -- up by 57% in the last week, according to federal data.

The U.S. is about 10,000 deaths away from reaching yet another grim milestone of 800,000 Americans lost to COVID-19. 

The U.S. is now averaging approximately 103,000 new cases per day, which is a 19% increase in the last week and a 62% jump since late-October, according to federal data.

Minnesota currently holds the country's highest case rate followed by Vermont and Wisconsin. Puerto Rico, Hawaii and Louisiana have the nation's lowest infection rate.

-ABC News' Arielle Mitropoulos

The TSA screened nearly 21 million travelers during the 10-day Thanksgiving holiday period. Despite new concerns over omicron, the agency expects to see the near pre-pandemic travel volumes continue through the December holidays.

-ABC News' Mina Kaji

The omicron variant of the virus that causes COVID-19 has been found in Houston’s wastewater, the Houston Health Department announced Monday night. "The detection is the first indication the new variant is in Houston, although a case has not yet been confirmed in the city," the department said.

Wastewater samples collected between Nov. 29 and Nov. 30 showed omicron at eight of the city’s 39 wastewater treatment plants, and the genomic sequencing results confirming the variant were received Monday evening.

"The Houston Health Department and Houston Water continue to do an exceptional job tracking the impact of the virus in our community. While no specific case of the Omicron variant has been confirmed in an individual in the city of Houston, we should use this information as a reminder to get fully vaccinated, including a booster shot," Houston Mayor Sylvester Turner said in a statement. "Vaccines help protect us, our loved ones, friends, and colleagues in the work environment. As the holidays approach, I encourage everyone to remain vigilant about their health and safety."

The health department said it routinely tests the city’s wastewater for COVID-19, including variants, and recently started testing samples for omicron, as "people infected with COVID-19 shed the virus in their feces."

"The wastewater data helps to more quickly identify emerging outbreaks and hotspots needing interventions to help stop the spread of the virus," the health department added.