US records first case of Omicron COVID-19 variant

The United States recorded the first confirmed case of the Covid-19 Omicron variant had been detected in California. A fully vaccinated traveller who recently returned from South Africa and was recovering from mild symptoms.

Top health official Anthony Fauci said authorities "knew it was only a matter of time" before the tribe was found in the country, reminding Americans that vaccination, boosters and masking in indoor public environments are the best way stay to stay protected.

According to the Centers for Disease Control and Prevention (CDC) statement, the person returned from South Africa on November 22, and their close contacts all tested negative.

Fauci spoke to reporters, adding that the patient tested positive on November 29 and that they did not get a booster to the best of his knowledge.

Some early press reports about the Omicron variant suggested it could cause more mild illnesses, but Fauci warned against reading too much into it until more hard data became available.

"We feel good that this patient not only had mild symptoms, but the symptoms seem to be improving," he said.

"But as we said, there is a lot of information now evolving from countries like South Africa that has a much larger number of individuals," with the variant, he added.

Such data should follow in the coming weeks and months. While the person in question has been fully vaccinated, Fauci stressed that a Covid enhancer remains a good idea because it increases the number of overall antibodies in a person's immune system, some of which will remain effective in stopping new variants.

"Our experience with variants like the Delta variant is that even though the vaccine is not specifically targeted to the Delta variant, you get flood protection when you get a high enough level of an immune response," he said.

Fauci also defended the US travel ban on southern African countries, which UN chief Antonio Guterres described as "unfair" and "ineffective".

"We had to buy time to prepare, to understand what was going on," he said.

"We wanted to make sure that we did not suddenly say it's like anything else, do not worry about it, and then suddenly something unfolds in front of you that you are not prepared for. We, therefore, consider it a temporary measure. "

To prepare for Omicron, the US is planning stricter testing and weighing quarantine requirements for international travellers arriving in the country, including taking a Covid-19 test one day before departure, the CDC said Wednesday.