The Omicron variant of coronavirus has now become the dominant strain of the virus in the United States, AFP quoted health authorities as saying on Monday.

The new variant accounted for 73.2% of coronavirus infections in the past week till Saturday, according to the country’s Centers for Disease Control and Prevention. In the week ending on December 11, the variant had accounted for just 12.6% of the coronavirus cases, CNN reported.

The new strain comprises over 90% of new Covid-19 cases in certain regions of the country, particularly the Pacific Northwest, South and parts of the Midwest.

The United States detected its first case of the Omicron variant 20 days ago. The strain has now been detected in 48 out of 50 states till Monday, with Oklahoma and South Dakota being the only states that have not found cases of Omicron yet.

However, White House Press Secretary Jen Psaki said on Monday that President Joe Biden is not planning on “locking the country down”. The president is expected to deliver an address on the coronavirus situation on Tuesday.

Meanwhile, Psaki told the media on Monday that a mid-level official tested positive for Covid-19 three days after being in proximity to Biden for about 30 minutes. “This staff member is fully vaccinated and boosted, and tested negative prior to boarding Air Force One, as is required for everyone traveling with the president,” she said.

The United States president got tested for Covid-19 on Monday after being notified about the official testing positive. He tested negative, and will get tested again on Wednesday.

Covid-19 in the US

The United States has been reporting a sharp surge in coronavirus cases in the past few weeks. Covid-19 cases that required hospitalisation in the country rose by 45% over the last month, according to Reuters.

Over the past one week, the country has recorded 1,23,000 cases on an average everyday. This marked a jump of 40% since last week.

The Omicron variant, which has a large number of mutations, was first detected in South Africa on November 24. Two days later, the World Health Organization declared it a “variant of concern”.

Last week, the World Health Organization said that the Omicron variant had been detected in 89 countries till December 16. It said that the strain was spreading fast even in countries with high levels of herd immunity.