The new Omicron variant of the novel coronavirus is continuing to build momentum in the United States, and now makes up the majority of confirmed cases nationwide. With Omicron cases doubling every 1.5 to three days in areas with community transmission, the variant is poised to fuel yet another wave of COVID-19 this winter. This has added urgency to recommendations for people aged 16 years and older who have received two doses of the mRNA vaccines from Pfizer and Moderna, or the single-dose Johnson & Johnson vaccine, to get a booster shot. To read the full story.