At this point in time, with experts assuming but not actually knowing the facts regarding the long term effects of these shots, I am assuming as well that two doses will not have a negative effect on most individuals taking these shots. However, they will need to be repeatedly injected every half a year or so, like flu shots are, likely every half a year or yearly, and I definitely believe repeated injections of these shots would be very dangerous to the human body.
As far as it’s effectiveness, studying the results in Israel, which now with a new lockdown looming, and other countries who have high doses of the shot per capita, it doesn’t seem like the shots have successfully eliminated the rising rates of coronavirus infections which is what they are intentend for