Effect of thermal ballast loading on temperature stability of domestic refrigerators used for vaccine storage

• DOI: 10.1371/journal.pone.0235777
• Publication Date: 2020-07-08T17:30:18Z
• Authors: Michal Chojnacky; Alexandra L. Rodr...
• Keywords: Ballast

Vaccine temperature control failures represent a significant public and private healthcare cost. Vaccines damaged by excessive heat or freezing lose their effectiveness, putting health at risk. Some vaccine administration programs recommend placing water bottles inside domestic refrigerators used for storage as thermal ballast, to mitigate excursion risks. However, the effect of variable ballast loading on refrigerator performance has not been thoroughly quantified documented, generalized programmatic recommendations are subject end-user interpretation. Here we show that load comprising ten fifteen percent total volume provides measurable stability during power outage events, maintaining temperatures between 2 °C 8 4 6 hours without power. Thermal usage does reliably reduce frequency severity excursions caused repeated door opening, accidental "door left open" defrost cycle activation. Use moderate is practical strategy mitigating risks in areas with frequent protracted outages, but practice limited benefit other adverse scenarios. Empowering providers make informed decisions about use materials supports better, safer management.