Amid a worldwide surge in cases of the Omicron variant of COVID-19, Wall Street began the week of Christmas in a slump. The S&P 500, Dow Jones Industrial Average and Nasdaq composite were all down roughly 1.8% at various points Monday.

Oil producers were some of the biggest losers Monday. U.S. crude fell 6% on concerns the Omicron variant could lead factories, airplanes and drivers to burn less fuel. Stocks that are associated with that reopening are also taking big hits. Royal Caribbean was down 3%, and airlines like United and Southwest were dropping significantly at the start of trading Monday.

Such Wall Street concerns were escalated when Israel announced Monday it would ban travel to the United States, Canada and eight other countries due to the spread of Omicron. Once authorized, the travel ban will take effect at midnight Wednesday morning.

Israel has seen a surge in new Omicron cases in recent weeks. It began closing borders and restricting travel in late November. As of Sunday, Israel’s Health Ministry has reported 175 cases of the new variant.

“Omicron is spreading fast. Our goal is to overcome this wave while keeping our economy and educational institutions going,” Israel Prime Minister Naftali Bennett said in a Sunday tweet. “We must delay the infection rate as much as possible and use the time we gain to vaccinate.”

The Monday morning slump followed similar drops across Europe and Asia. Germany’s DAX lost 1.9% and Japan’s Nikkei 225 dropped 2.1%. The slump comes as European countries are weighing the possibility of more lockdowns and other increased COVID-19 restrictions related to the Omicron variant. The Dutch government began a tough nationwide lockdown on Sunday. On Monday, a U.K. official said he could not guarantee new restrictions would not be announced this week.

One company that actually got a Wall Street boost thanks to Omicron was Moderna. The company’s shares rose 6.7% to $314.51 in early trading in response to data released by Moderna Monday morning. That data showed Moderna’s booster shot “can boost neutralizing antibody levels 37-fold higher than pre-boost levels” to fight the Omicron variant.

“To respond to this highly transmissible variant, Moderna will continue to rapidly advance an Omicron-specific booster candidate into clinical testing in case it becomes necessary in the future,” Moderna CEO Stéphane Bancel said in a news release.