In just one week, the Centers for Disease Control and Prevention data showed a nearly six-fold increase of omicron infections.
It's higher in many parts of the country. Omicron is responsible in 90% of all new infections in the New York, Southeast, Midwest, and Pacific Northwest. According to the national rate, more than 650,000 Omicron infections were reported in the United States last week.
The main variant causing U.S. infection was the delta variant since June. According to CDC data, delta was responsible for more than 99.5% coronavirus infections as recently as November.
Dr. Rochelle Walensky, Director of the CDC, stated that the new numbers reflect growth in other countries.
She said, "These numbers may seem stark but it's not surprising."
Scientists in Africa raised the alarm about the omicron virus less than a month before it was discovered. The World Health Organization declared it a "variant concern" on Nov. 26, and the mutant has been found in approximately 90 countries.
Many details about the omicron variant remain unknown. This includes whether it causes more severe or less severe illnesses. Early research suggests that booster shots are necessary to prevent omicron infections. However, even without this extra dose, vaccines should still provide strong protection against serious illness and death.
"All of us have an omicron date," Dr. Amesh Adalja, senior scholar at Johns Hopkins Center for Health Security, said. "If you want to interact with the society, if your life is going to be meaningful, omicron will be a part of it. The best way to encounter it is to get fully vaccinated."
Adalja stated that he wasn't surprised by the CDC data showing that delta was being overtaken in the U.S. due to what had been seen in South Africa and the U.K. as well as Denmark. He expected spread during the holidays, including breakthrough infection among the vaccinated, and serious complications among those who aren't vaccinated. This could put pressure on hospitals already burdened with delta.
Dr. Eric Topol of Scripps Research Translational Institute said that while other countries have experienced omicrons' rapid growth, the data from the United States showed a "remarkable jump in such short time".
Topol said that it was not clear how milder omicron is in comparison to other variants. "That's where the real uncertainty lies now."
The CDC estimates are based upon thousands of coronavirus samples collected every week by state and local health departments, as well as commercial and university laboratories. Scientists examine their genetic sequences in order to determine which COVID-19 virus versions are most prevalent.
After analyzing more samples, the CDC updated its estimate of omicron cases in the week ending Dec. 11. The CDC reported that 13% of cases in the week ended Dec. 11 were from omicron. This is compared to the previously reported 3%. Omicron was only 0.4% of all cases the week before.
Officials at the CDC said that they don't yet know how many deaths or hospitalizations are caused by omicron.
Walensky stated that although there are still many new infections due to the delta variant, "I expect that over time that Delta will be crowded outby omicron."
