good! autumn and winter are the seasons when respiratory infections are more common. to acknowledge and scientifically respond to infectious diseases, protect our physical health together. here is a call for action: the flu (also known as influenza) is an acute respiratory infectious disease caused by the influenza virus. it poses a significant threat to human health and can cause seasonal outbreaks every year. the main mode of transmission is through respiratory droplets. due to its high incidence rate, rapid spread, and widespread susceptibility among the population, it primarily affects older adults, children, medical personnel, and individuals with weakened physical conditions. these groups are particularly vulnerable in schools, daycare centers, nursing homes, and other crowded settings. preventive measures: vaccination is the most effective way to prevent flu, reduce the risk of severe complications, and death. previous vaccinations can provide protection for 6-8 months. however, immunity will wane over time, so annual vaccination is necessary to maintain immunity. ideally, vaccination should be completed by late october. if not done by then, it can still be done throughout the flu season.