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Aim: Insulin loses potency when stored at high temperatures. Various clay pots part-filled with water, and other evaporative cooling devices, are used in less-resourced countries when home refrigeration is unavailable. This study examined the cooling efficacy of such devices., Methods: Thirteen devices used in Sudan, Ethiopia, Tanzania, Mali, India, Pakistan and Haiti (10 clay pots, a goat skin, a vegetable gourd and a bucket filled with wet sand), and two identical commercially manufactured cooling wallets were compared. Devices were maintained according to local instructions. Internal and ambient temperature and ambient humidity were measured by electronic loggers every 5 min in Khartoum (88 h), and, for the two Malian pots, in Bamako (84 h). Cooling efficacy was assessed by average absolute temperature difference (internal vs. ambient), and % maximal possible evaporative cooling (allowing for humidity)., Results: During the study period, mean ambient temperature and humidity were 31.0°C and 32.0% in Khartoum and 32.9°C and 39.8% in Bamako. All devices reduced the temperature (P < 0.001) with a mean (sd) reduction from 2.7 ± 0.5°C to 8.3 ± 1.0°C, depending on the device. When expressed as % maximal cooling, device efficacy ranged from 20.5% to 71.3%. On cluster analysis, the most efficacious devices were the goat skin, two clay pots (from Ethiopia and Sudan) and the suspended cooling wallet., Conclusions: Low-cost devices used in less-resourced countries reduce storage temperatures. With more efficacious devices, average temperatures at or close to standard room temperature (20-25°C) can be achieved, even in hot climates. All devices are more efficacious at lower humidity. Further studies are needed on insulin stability to determine when these devices are necessary., (© 2016 Diabetes UK.)

Typically, vaccines distributed through the Expanded Program on Immunization (EPI) use a 2-8°C cold chain with 4-5 stops. The PfSPZ Vaccine comprises whole live-attenuated cryopreserved sporozoites stored in liquid nitrogen (LN(2)) vapor phase (LNVP) below -140°C and would be distributed through a LNVP cold chain. The purpose of this study was to model LNVP cold chain distribution for the cryopreserved PfSPZ Vaccine in Tanzania, estimate the costs and compare these costs to those that would be incurred in distributing a 'conventional' malaria vaccine through the EPI. Capital and recurrent costs for storage, transportation, labor, energy usage and facilities were determined for the birth cohort in Tanzania over five years. Costs were calculated using WHO/UNESCO calculators. These were applied to a 2-8°C distribution model with national, regional, district, and health facility levels, and for the cryopreserved vaccine using a 'modified hub-and-spoke' (MH-S) LNVP distribution system comprising a central national store, peripheral health facilities and an intermediate district-level transhipment stop. Estimated costs per fully immunized child (FIC) were $ 6.11 for the LNVP-distributed cryopreserved vaccine where the LN(2) is generated, and $ 6.04 with purchased LN(2) (assuming US $ 1.00/L). The FIC costs for distributing a conventional vaccine using the four level 2-8°C cold chain were $ 6.10, and with a tariff distribution system as occurs in Tanzania the FIC cost was $ 5.53. The models, therefore, predicted little difference in 5-year distribution costs between the PfSPZ Vaccine distributed through a MH-S LNVP cold chain and a conventional vaccine distributed through the more traditional EPI system. A LNVP cold chain provides additional benefits through the use of durable dry shippers because no refrigerators, freezers or refrigerated trucks are required. Thus strain at the cold chain periphery, vaccine wastage from cold chain failures and the environmental impact of distribution would all be reduced., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

A study was carried out in Tabora region to determine the magnitude of exposure of vaccines to adverse temperatures using the Cold Chain Monitors (CCMs). Except for refrigerators in the regional hospital, almost all refrigerators were found to be exposed to adverse temperature. The RAK type of refrigerators were found to be more exposed to adverse temperature than the RCW type. While an alternative type of refrigerator suitable for tropical countries is being sought there is a need of focusing more attention on improving cold chain system in the peripheral facilities.