Kumar Sandeep, Lennon Pat, Muller Nancy, Uranw Surendra, Mvundura Mercy, Sibole Alexandra, Diesburg Steven, Little Joe, Ray Arindam, Sharma Gautam Jhalak, Rajbhandari Singh Rupa, Jha Nilambar
PATH, New Delhi, India.
PATH, Seattle, WA, USA.
Vaccine X. 2022 Feb 11;10:100146. doi: 10.1016/j.jvacx.2022.100146. eCollection 2022 Apr.
Preventing vaccine freezing is one of the biggest challenges in vaccine management. Until 2018, vaccine carriers used in the immunization program lacked features to prevent vaccine freezing. Freeze-preventive vaccine carriers (FPVCs) have an engineered liner that buffers vaccines from direct exposure to frozen ice packs. A field evaluation of three FPVCs was conducted in 24 health posts in eastern Nepal. The objective was to evaluate the FPVCs' performance, acceptability, systems fit, and cost, to inform prequalification and introduction planning. The study was carried out in two phases: in the first phase, FPVCs containing dummy vaccines (labeled "Not for Human Use") were transported to outreach sessions along with a standard vaccine carrier (SVC); in the second phase, the FPVCs were used for transporting vaccines taken to outreach sessions and used for vaccinating eligible children. The study gathered quantitative and qualitative data from health workers, logbooks, and electronic temperature monitors placed inside and outside the FPVCs. Results indicate the FPVCs successfully prevented temperatures below 0 °C more than 99% of the time-except at one site, where ambient temperatures were below the minimum rated testing temperature specified by the World Health Organization. Internal cool-down times for the FPVCs were highly variable, as were mean kinetic temperatures, possibly driven by the wide range of ambient temperatures and higher-than-expected variations in freezer performance, which, along with the need to transport ice packs to some locations, affected ice-pack temperatures. Almost all health workers requested smaller, lighter-weight FPVCs but appreciated the FPVCs' ability to prevent vaccines from freezing while avoiding undue heat exposure. FPVCs had benefit-cost ratios greater than 1 and hence good value for money. Results point to the importance of understanding the intended environment of use and the need for smaller, short-range as well as long-range carriers.
防止疫苗冻结是疫苗管理中最大的挑战之一。直到2018年，免疫规划中使用的疫苗运输箱都缺乏防止疫苗冻结的功能。防冻疫苗运输箱（FPVC）有一个经过设计的内胆，可缓冲疫苗，使其不直接接触冷冻冰袋。在尼泊尔东部的24个卫生所对三种FPVC进行了现场评估。目的是评估FPVC的性能、可接受性、系统适配性和成本，为预认证和引入规划提供依据。该研究分两个阶段进行：在第一阶段，装有虚拟疫苗（标签为“非供人类使用”）的FPVC与标准疫苗运输箱（SVC）一起被运送到外展接种点；在第二阶段，FPVC用于运输送往外展接种点的疫苗，并用于为符合条件的儿童接种疫苗。该研究从卫生工作者、日志以及放置在FPVC内外的电子温度监测器收集了定量和定性数据。结果表明，除了一个环境温度低于世界卫生组织规定的最低额定测试温度的地点外，FPVC在超过99%的时间内成功防止了温度低于0°C。FPVC的内部冷却时间变化很大，平均动力学温度也是如此，这可能是由环境温度范围广泛以及冷冻性能的变化高于预期所驱动的，这与需要将冰袋运送到某些地点一起，影响了冰袋温度。几乎所有卫生工作者都要求提供更小、更轻的FPVC，但赞赏FPVC防止疫苗冻结同时避免过度受热的能力。FPVC的效益成本比大于1，因此性价比高。结果表明了解预期使用环境的重要性，以及对更小、短程和远程运输箱的需求。
