By Joseph Ax and Barbara Goldberg (Reuters) -Two years into the coronavirus pandemic, the United States is confronting another dark winter, with the red-hot Omicron variant threatening to worsen an already dangerous surge of cases. Hospitalizations for COVID-19 have jumped 45% over the last month, and confirmed cases have increased 40% to a weeklong average of 123,000 new U.S. infections a day, according to a Reuters tally. Pfizer Inc, one of the chief vaccine makers, on Friday predicted the pandemic would last until 2024 and said a lower-dose version of its vaccine for children ages 2 to 4 ge…