The omicron Covid-19 variant has quickly overtaken delta as the dominant strain of the virus across the U.S., accounting for 90% of the cases in some parts of the country, CDC director Dr. Rochelle Walensky said Wednesday.
The variant makes up more than 73% of the cases in the United States as of Saturday, according to the latest data released by the Center for Disease Control and Prevention. Last week, U.S. health officials said omicron accounted for 2.9% of all cases sequenced through Dec. 11, but later revised that number up to 12.6%.
Walensky said the highly mutated and contagious strain accounts for up to 90% of the infections in the eastern Atlantic states, parts of the Midwest, South and northern Pacific states.
"This rapid increase in the proportion of omicron circulating around the country is similar to what we've seen across the world," she told reporters during a White House Covid-19 press briefing.
Unvaccinated people are 10 times more likely to get Covid-19 and 20 times more likely to die from the virus when compared to a person who is fully vaccinated and received their booster, according to CDC data collected in November when delta was the dominant variant.
"Early data on the vaccine is promising against the omicron variant," Walensky said. "Especially when people are boosted."
Walensky and White House chief medical advisor Dr. Anthony Fauci encouraged people to get tested for Covid before meeting up with friends or family over the holidays and recommended celebrating at home with others who are also vaccinated to reduce the chance of transmission.
Jeff Zients, White House Covid-19 response coordinator, said Pfizer's anti-viral treatment Paxlovid, which was authorized by the FDA earlier Wednesday, was "very promising."
According to Zients, the Pfizer pill is expected to "dramatically reduce" the risk of hospitalizations and deaths. The Pfizer pill has a 90% efficacy rate in preventing hospitalizations.
The U.S. purchased 10 million treatment courses of the Pfizer pill and is expected to have 265,000 treatment courses available in January.
The Merck pill is awaiting clearance from the FDA, which could come this week.