Adviser: Omicron could become dominant in France within weeks

PARIS/WASHINGTON DC: Omicron could become the dominant COVID-19 variant in France by the end of January, the top scientific adviser said on Thursday, after both France and the United States reported their first cases and countries around the world tightened curbs.

The first known U.S. case was a fully vaccinated person in California who returned to the United States from South Africa on Nov. 22 and tested positive seven days later. The French case, in the greater Paris region, was a passenger arriving from Nigeria.

US President Joe Biden is working on a strategy to fight COVID-19 this winter and sources briefed on the matter told Reuters one step would be extending requirements for travellers to wear masks through mid-March. A formal announcement is expected on Thursday.

The White House also plans to announce stricter testing for international visitors.

French government adviser Jean-Francois Delfraissy told BFM television the "true enemy" for now was still the Delta variant, spreading in a fifth wave. "We should see a progressive rise of the Omicron variant, which will take over from Delta," possibly by the end of January, he said.

"Christmas is not at risk if the population and decisionmakers are all very cautious," he said, reiterating that social distancing and a third, booster shot of vaccines were key.

The French Omicron infection followed a case found in the French Indian Ocean island of La Reunion last month.

Airlines in the United States were told to hand over the names of passengers arriving from parts of southern Africa, a U.S. Centers for Disease Control and Prevention letter seen by Reuters showed.

Much remains unknown about Omicron, which was first found on Nov. 8 in South Africa and has spread to at least two dozen countries, just as parts of Europe were suffering a surge in infections of the better-known Delta variant as winter sets in.

Top U.S. infectious disease expert Anthony Fauci on Wednesday said it could take two weeks or more to gain insight into how easily the variant spreads, the severity of the illness that it causes and whether it can evade currently available vaccines.