Once in a while, we all succumb to seasonal influenza, commonly known as the flu.
Seasonal influenza outbreaks are caused by small changes in viruses that are already circulating around us, and to which many people have some immunity.
Once in a while, we all succumb to seasonal influenza, commonly known as the flu.
Seasonal influenza outbreaks are caused by small changes in viruses that are already circulating around us, and to which many people have some immunity.