Which storage condition is most detrimental to vaccine efficacy?

Freezing is the most detrimental storage condition for many vaccines because it can cause irreversible damage to the vaccine's formulation. Most vaccines are designed to be stored in refrigerated conditions where the temperature is maintained between 2°C and 8°C. When vaccines freeze, ice crystals can form within the solution, potentially destabilizing the active components and rendering the vaccine ineffective.

While refrigeration is the recommended storage condition and room temperature may be tolerated for short periods depending on the vaccine type, both of these conditions are less harmful compared to freezing. Direct sunlight exposure can degrade some vaccines but generally presents a lesser risk than the structural changes caused by freezing. Therefore, it’s essential to adhere to proper storage guidelines to maintain vaccine efficacy.