Flu season comes around like clockwork every year, and sooner or later everyone gets infected. The annual flu shot is a key part of public health efforts to control the flu, but the vaccine’s effectiveness is notoriously poor, falling somewhere from 40% to 60% in a typical year.
A growing body of evidence suggests that a history of exposure to influenza virus might be undermining the effectiveness of the annual flu vaccine. Partial immunity developed during prior flu seasons — either through natural infection or vaccination — might interfere with the body’s response to a new vaccine, such that vaccination mainly boosts the recognition of prior influenza strains but does little to create the ability to fight new strains.
Chest infection from spraying Flea Spray (or was it just bad luck, flu season or allergy?)
Just like busses...! 
sudden Bronchiectasis exacerbation.
Adult whooping cough - second time!
