UPDATE 1-Nebraska is sixth U.S. state with Omicron coronavirus variant

(Adds U.S. CDC director quotes, details on spread of variant)

WASHINGTON, Dec 3 (Reuters) - A sixth U.S. state - Nebraska - reported the Omicron variant of the coronavirus after detecting six confirmed cases of the highly contagious strain, the state's health department said on Friday.

Only one of the six people was vaccinated and none have needed to be hospitalized with COVID-19, the department said.

One case involved a traveler who returned from Nigeria on Nov. 23, while the other five cases were likely exposed through household contact with that same person, the department said.

While Omicron has been grabbing headlines as the newest coronavirus variant in the United States, the predominant strain remains the Delta variant, said U.S. Centers for Disease Control and Prevention Director Rochelle Walensky at a White House briefing.

"I know that the news is focused on Omicron. But we should remember that 99.9% of cases in the country right now are from the Delta variant. Delta continues to drive cases across the country, especially in those who are unvaccinated," she added.

The CDC is working with local authorities to investigate suspect cases of the Omicron variant of COVID-19 in states other than those where cases have already been reported, she said.

There have been cases of Omicron detected in about 40 countries, including the United States, where it was found in California, New York, Colorado, Minnesota, Hawaii and Nebraska.

Health policy researcher Dr. Kavita Patel on Friday urged people to be patient as they seek booster shots amid Omicron's arrival, saying there was plenty of supply even as cases spike with Delta-related infections in the U.S. Northeast and Midwest.

"It's here. We've seen community spread from Hawaii to New York," Patel, a former health policy official under former President Barack Obama, told MSNBC, where she is a news contributor. "It's good that the vaccinated ones we've seen have been mild so far." (Reporting by Caitlin Webber, Tim Ahmann and Susan; additional reporting by Barbara Goldberg; editing by Tim Ahmann and Grant McCool)