CTTBD EXPLORES THE USE OF DRY ICE AS AN ALTERNATIVE TO LIQUID NITROGEN FOR STORAGE OF EAST COAST FEVER VACCINES


The Centre for Ticks & Tick-borne Diseases (CTTBD), an institution based in Lilongwe, Malawi, has a mandate to support the control of livestock diseases and the development of the livestock industry in Africa through research and production of quality assured veterinary vaccines for tick-borne diseases.

In October, 2020, CTTBD entered into a partnership with a US based company, GH Labs, which proposes to develop technologies that use dry ice as an alternative to liquid nitrogen in the delivery and storage (last mile delivery) of the East Coast Fever (ECF) vaccines that require ultra-low temperatures into the low resource geographical settings of Africa.

A team of experts from VetLife Consultancy (led by Mr. Juma Abinala) from Mbeya, Tanzania, delivered a prototype of a Dry-ice making machine to CTTBD in December, 2020 and trained the local technical staff how to produce the dry-ice to be used in an experiment to assess the viability of the live Muguga Cocktail vaccine after storage for 30 days in dry-ice.





Mr. Juma Abinala, teaching the CTTBD technical staff how to make dry ice pellets from Carbondioxide




Freshly produced dry ice pellet for use in the Alban dewar flask

Preliminary in vitro and in vivo studies showed that step-down of storage conditions of the Muguga Cocktail vaccine from -196 ⁰C to -80 ⁰C (in ultra-freezers) for 30 days had no effect on viability of the sporozoites (Atuhaire et al., 2020). https://doi.org/10.1016/j.vetpar.2020.109304

The aforementioned findings created a platform for more comparative studies that CTTBD embarked on recently to test the viability of the Muguga Cocktail vaccine stored in the ALBAN DEWAR flasks for a 30-day period on dry-ice in comparison with the conventional liquid nitrogen storage.

The Flask was designed by GH Labs and licensed to Carbacid LTD CO2 supplier based in Nairobi.Carbacid will sell the flask as the Alban in mid 2020.  The Alban Flask uses dry-ice to maintain sufficient cryogenic temperatures.  The dewar is equipped with the centre tube, a canister that sits inside the centre tube to hold the payload (e.g. ECF vaccine, bull semen straws). The canister can hold up to thirty (30 x 0.5 mL) straws in the centre tube that is surrounded by the dry-ice.  The centre tube is colour-coded to indicate the minimum dry-ice filling level that will ensure that the correct temperature is maintained.





Muguga Cocktail vaccine being transferred from liquid nitrogen flask into the Alban dewar flask for the comparative studies.

Currently, the comparative studies are underway and the results and conclusions will be drawn once the studies are concluded.

Authored by: Dr. David Kalenzi Atuhaire, R & D Manager, CTTBD

Edited by: Dr. Namukolo Muyamwa, QA Manager, CTTBD

For CTTBD News updates/2021

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