Don't take any generic crap - injected or otherwise - simply buy this product and when you feel symptons coming on - take it and it will go away.
I spend a fortune every month eating organic food etc I know my stuff - I recommend this to EVERYONE - I have not had a flu develop beyond a few hours of discomfort for the last 3 yrs since I started taking it nor has anyone I know who takes it. This company Boiron also makes remedies for regular colds also. This stuff works - period end of story.
http://www.oscillo.com/
Most natural food stores sell it and lately more and more generic stores sell it also.