The United States and several other nations are reporting higher rates of the flu compared with past seasons. American health officials say the winter outbreak is expected to be one of the most severe in 15 years, with up to 34 million people infected. Across the U.S., 1 in 15 doctor visits last week were related to the flu the highest level since the 2009 swine flu pandemic. Before that outbreak, the last time the U.S. experienced such high levels of seasonal flu was in 2003-2004. The U.S. Centers for Disease Control and Prevention or CDC said last week that flu cases are currently active in all U.S. states except for Hawaii. All remaining 49 states have reported widespread flu activity for the past three weeks.