1 BACKGROUND Influenza viruses are among the most widespread and contribute to pandemic viruses worldwide, demonstrating a catastrophic impact on human health.1 The World Health Organization reported that the annual incidence of influenza in adults is 10% globally, and the annual incidence of influenza in children is 20%–30%.2 It is worth noting that influenza outbreaks can cause 3,000,000–5,000,000 severe cases and 290,000–650,000 deaths each year.3 Some severe cases are prone to viral...