Adults over the age of 30 only catch flu about twice a decade, reveals a study published in PLOS Biology.

Adam Kucharski said, "There's a lot of debate in the field as to how often people get flu, as opposed to flu-like illness caused by something else. These symptoms could sometimes be caused by common cold viruses, such as rhinovirus or coronavirus. Also, some people might not realize they had flu, but the infection will show up when a blood sample is subsequently tested."
The findings will help understand how the immunity in the population affects the evolution of flu viruses, and potentially make predictions about how the virus will change in the future. It could also help scientists consider how immunity to historical strains will influence the way vaccines work and how effective they will be.
Source-Medindia