BRASILIA (Reuters) -New cases of COVID-19 in the Americas in the past week have been the highest since the pandemic began in 2020 and the very contagious Omicron variant has clearly become the predominant strain, the Pan American Health Organization said on Wednesday. There were more than 8 million new cases, 32% higher than the previous week, while fatalities throughout the region also increased by 37%, with 18,000 new deaths caused by COVID-19. The United States continues to have the highest number of new infections, although cases decreased by nearly 1 million over the last week, the region…