Having influenza once can produce antibodies, but it does not necessarily prevent the next influenza infection. The pathogen of influenza is influenza virus. Having influenza once will produce antibodies to the corresponding subtype of the virus, but the surface antigen of influenza virus is prone to mutate and produce new subtypes, and there is often no cross-immunity between different viral subtypes, therefore, even if you have had influenza, you may not necessarily be able to prevent the next influenza infection. Influenza is mainly transmitted through droplet transmission and contact transmission, often outbreaks in the fall and winter, the population is generally susceptible, it is recommended that children, pregnant women, the elderly and immunocompromised people of the population every year in advance to receive influenza vaccine, to avoid going to the areas where the population gathers, go out to wear a mask, timely hand hygiene to prevent infection. To summarize, the effect of influenza antibody protection is poor, it is recommended to do a good job of protection during the high incidence of influenza to prevent infection.