Waning immunity against COVID variants can be influenced by several factors. One key factor is the duration since receiving a booster shot or vaccination, as over time, the effectiveness of the vaccine may decrease. Additionally, the ability of new variants like XBB 1.5 and EG.5 to evade the immune response plays a significant role in waning immunity. Variants with mutations that alter their spike proteins can make it harder for antibodies generated from previous infections or vaccinations to recognize and neutralize them effectively.