I travelled to southern Africa in 2011 and needed the Yellow Fever jab - I think it was to get back into South Africa after having been to Zambia (even though I didn't travel to an area with Yellow Fever, the officials at the airport don't know where we've been, do they). And I remember, I think all of the internal flights in Africa were fumigated - they tell you to cover your eyes and mouth so it must be something potent!
I didn't experience any side effects from the injection at all.
RM.