According to public information, there are more than 6 million flu cases in the United States in the flu season of 2022, and there is a high probability that they will be imported into the mainland of China.
Influenza is a disease caused by virus, which is highly contagious. Influenza is caused by different types of viruses. There are three types of influenza known, namely, A, B and C, among which A is more common.