Obesity may also impact flu transmission, not just severity of illness

"Obesity increases a person's risk for severe complications from influenza, including hospitalization and even death. It may also play a role in how flu spreads, according to a new study published in The Journal of Infectious Diseases. The findings suggest that obese adults infected with flu shed the virus for a longer time than adults who are not obese, potentially increasing the opportunity for the infection to spread to others."