Influenza H3N2 refers to Influenza A H3N2. Influenza A H3N2 is spread through the respiratory tract. Influenza A H3N2 is a respiratory disease caused by the influenza A H3N2 virus, which can be transmitted through the respiratory tract. If droplets with influenza A (H3N2) virus particles are transmitted through the respiratory tract, they cause the respiratory ciliary epithelial cells to become infected, denatured, necrotic, and detached, resulting in an inflammatory response. The susceptible population of influenza A H3N2 includes children and the elderly, the high incidence period is usually in summer and winter, and its transmission capacity is strong. Patients tend to show symptoms of influenza, such as fever, cough, headache, chills, and weakness of limbs, but it may also be combined with pneumonia and respiratory failure, and even lead to death. At present, influenza A H3N2 can be prevented by vaccination. Susceptible people such as the elderly and children with low resistance can receive the relevant vaccine in time before the high incidence of the active, and the antibody can be produced generally after 2 weeks, thus preventing the virus from infection. Influenza A H3N2 can be transmitted through the respiratory tract. During the influenza epidemic, attention should be paid to wearing masks when going out and avoiding contact with infected patients, so as not to lead to the attack of the virus.