While the new omicron variant of the COVID-19 virus has not yet been detected in the United States, it will "inevitably" arrive, Dr. Anthony Fauci said Sunday.

"We all know when you have a virus that has already gone to multiple countries, inevitably it will be here," Fauci told ABC's "This Week" anchor George Stephanopoulos. "The question is, will be prepared for it?

-ABC News' Bill Hutchinson

As concerns grow with the omicron COVID-19 variant, two of the world's major coronavirus vaccine makers said they'll be able to develop a vaccine to combat the new variant.

Pfizer/BioNTech said that if a "vaccine-escape variant emerges," they "expect to be able to develop and produce a tailor-made vaccine against that variant in approximately 100 days, subject to regulatory approval."

"Pfizer and BioNTech are remaining vigilant, and we are constantly conducting surveillance efforts focused on monitoring for emerging variants that potentially escape protection from our vaccine," the company said in a statement to ABC News.

Similarly, Moderna's Chief Medical Officer Paul Burton told the BBC's Andrew Marr on Sunday that they've mobilized hundreds of employees starting on Thanksgiving and expect to know the ability of the current vaccine to provide protection against the new variant "in the next couple of weeks."

 "If we have to make a brand-new vaccine, I think that's going to be early 2022 before that's really going to be available in large quantity," he told the BBC.

-ABC News' Ahmad Hemingway

As countries around the world prepare for the spread of the omicron variant, one of the U.S.'s largest manufacturers of COVID-19 tests says it is "confident" its products will detect the new strain.

"Abbott has been intently monitoring the mutations of COVID-19 so we can ensure our tests can detect them," Abbott Laboratories said in a statement Saturday night. "We have already conducted an assessment of the Omicron variant and we're confident our rapid and PCR tests can detect the virus. While the Omicron variant contains mutations to the spike protein, Abbott's rapid and PCR tests do not rely on the spike proteins to detect the virus."

Abbott said both its ID NOW tests, used by medical professionals, and BinaxNOW tests, sold for at-home use, have been shown to detect the virus.

The company is currently manufacturing 100 million tests a month for use worldwide. The U.S. government is among those to have purchased the tests, with President Joe Biden announcing in late September that millions of dollars worth of tests would be purchased.

The omicron strain, first detected in southern Africa, has now been identified in several European countries. It was declared a variant of concern by the World Health Organization on Friday.

Israel has become the latest country to institute a travel ban due to the newly emerged omicron variant -- and it's going a step further than other countries.

The country announced Saturday it will be closing its borders to all foreign travelers -- not just those from southern Africa -- for two weeks starting at 12:01 a.m. Monday, the government said. Unvaccinated Israelis who return from overseas will be forced to take a PCR test upon landing and enter home isolation. They will receive a second PCR test on the third day of isolation and be allowed to resume their normal activities if negative.

Israelis returning to the country from certain high-risk countries will be forced to isolate at a hotel until receiving two negative tests.

The country said plans instituted last week to deal with Hanukkah celebrations, including limits on the size of gatherings, will remain unchanged. Hanukkah begins on Sunday.

-ABC News' Joshua Hoyos