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With omicron spreading globally at a dizzying pace, scientists are scrambling to learn as much as they can about the latest worrisome variant of the coronavirus. First spotted in South Africa and Botswana at the end of November, omicron is already poised to soon become the dominant variant — dethroning delta — in some regions, public health officials warn. In a few places, it already has. So answers, including how sick does omicron make people and how well do vaccines hobble it, can’t come fast enough.

A rising tide of data on omicron is beginning to provide a glimpse at what’s ahead as we enter year three of the global pandemic, though many questions linger. And with many people preparing to gather with family and friends for holidays, experts are bracing for yet more case surges, compounded by already high infection rates in some countries linked to the still-prevalent delta variant.

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Omicron’s collision with the holidays and travel is “a perfect storm,” Thomas Denny, a vaccine expert at Duke University, said December 16 in a call with journalists. At this point, even vaccinated people should be taking precautions, such as wearing masks indoors and testing before family gatherings, he said. “This new variant has thrown us a curve ball at the worst possible time.”

Still, amid the worries, there are positive signals that vaccines can still protect people from the worst of COVID-19. As many countries hurtle toward a season of omicron, here’s what researchers are learning so far.