Harvard ES21 Fall 2011

Vaccine Freeze Detection

Transcript

1. Vaccine Freeze Detection Kane Hsieh & William Morrow
2. Problem To remain effective, Class C vaccines can’t be frozen. Diptheria Typhoid Tetanus Influenza Hep B Whooping Cough Pneumococcal Polio
3. Problem Due to human error within the cold chain a majority of these vaccines are subjected to some degree of freezing throughout their lives. • Placing a box too near the sides of a refrigerator • Near a vent • On dry ice At least 75% of these vaccines are frozen at some point during their lives
4. Problem The reason this is bad is because crystallization decreases the potency of Class C vaccines Alluminum particles clump together rendering the vaccine useless
5. Current tech FreezeWatch Attached to outside of box Detects freezing temperature
6. Problems with current tech • Real problem is ice crystallization ◦ Temperature does not accurately determine the formation of ice • Location makes it prone to false positives ◦ The single monitor is not accurate enough to detect if an entire box has been frozen If FreezeWatch detects freezing temperatures then the whole box, with thousands of vaccines, must be thrown away
7. Our implementation • Based on existing technology (fast food onion rings, among others) • Low cost - no exotic materials • VVM level granularity • Detects crystallization
8. What's next? Continue research on membrane thickness and monitor placement