Why are there so many flu in America?

Without protection. According to the information about flu, most of the flu in the United States is because they are not well protected. When Americans have a fever, cough and poor breathing, they will definitely go to the hospital, and the hospital will test the flu virus. There are many kinds of influenza viruses, such as H 1N 1, H2N3 and even N5. The classification of influenza adenovirus is very clear, and each case will be reported to the CDC, so as to accurately count the number of influenza patients and the mortality rate.