If i get a booster, should i change the brand of booster vs. my original vaccine? is it more effective? i have seen some things say the booster immunity wanes some after 2.5 months - how much does it wane? how much does booster reduce severe illness?

The effect of a "booster shot" of the same vaccine received by the first two vaccine shots does reduce statistically the infection rate, and prevents by extension the length of protection from the first two shots. It has not been determined how much time is gained but the statistics of severity of infection and hospitalization is a valid reason to receive the booster shot.

Best get boosted with original vaccine since you had no side effects. Another brand could cause none or some side effects. Why take a chance .Six months is good antibody buildup but you can still get a breakthrough with little problems or none. Still wear a mask and stayaway from strangers and crowds.