The CDC estimates around 30 million symptomatic influenza infections in a year; in recent years, more[1]. And roughly three-quarter of infections are asymptoma

The CDC estimates around 30 million symptomatic influenza infections in a year; in recent years, more[1]. And roughly three-quarter of infections are asymptomatic[2], so ~120 million total cases annually. [1]: https://www.cdc.gov/flu/about/burden/past-seasons.html https://www.cdc.gov/flu/about/burden/past-seasons.html [2]: https://www.sciencedirect.com/science/article/pii/S2213260014700347 https://www.sciencedirect.com/science/article/pii/S221326001...