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Refrigeration, a key player to eradicate malaria

Refrigeration techniques have been used to develop and preserve the very first malaria vaccine, which has been administered to almost 2 million children since 2019.

Every year on 25 April, the World Health Organization (WHO) aims to highlight the need for continued investment and sustained political commitment for malaria prevention and control.

 

In 2022, malaria was responsible for 608,000 deaths, with 95% of malaria cases and deaths occurring in sub-Saharan Africa, and the remainder in South-East Asia and South America. [1] Children under the age of 5 are the most vulnerable group.

Malaria is a protozoan infection of red blood cells transmitted through the bite of an infected female anopheline mosquito. Symptoms range from fever, headache and chills to extreme tiredness and fatigue, convulsions, difficulty breathing and eventually death in severe cases. [1, 2] Malaria is a curable disease, but it is difficult to prevent and treat due to the high adaptability of the vector and parasites involved.

 

The first-ever malaria vaccine was formulated using lyophilisation and must be stored at 2° to 8°C.

 

In October 2021, the WHO recommended he widespread use of Mosquirix (RTS,S/AS01), a recombinant protein-based vaccine for children at risk of contracting malaria.

The Mosquirix vaccine is made of two vials. One vial contains lyophilised antigen (RTS, S) which must be reconstituted with the second vial containing the adjuvant system (AS01) in liquid form. [3, 4]

Lyophilisation is a process for dehydrating a substance by freezing followed by sublimation of the ice formed. The lyophilised antigen is thermostable, whereas the liquid part is temperature sensitive. To simplify the storage procedure, it is recommended to store both antigen and adjuvant between 2 and 8 °C. [3]

Since 2019, the Mosquirix (RTS,S/AS01) vaccine has been administered to about 2 million children in Ghana, Kenya and Malawi, resulting in a 13% reduction in child deaths and a substantial reduction in the number of children admitted to hospital with severe malaria. [5]

 

The WHO recommends that the malaria vaccine should be provided as part of a comprehensive malaria control strategy. The highest impact is achieved in association with other malaria control interventions. [3]

 

For more information, please visit the WHO website.

 

 

Sources 

[1] https://www.who.int/news-room/fact-sheets/detail/malaria 

[2] Gnaneswaran, B., & Gladstone, M. (2021). The febrile illness of malaria: an overview of assessment, management and its prevention. Paediatrics and Child Health, 31(4), 163-166. https://doi.org/10.1016/j.paed.2021.01.006  

[3] Malaria vaccine: WHO position paper – March 2022. https://www.who.int/publications/i/item/who-wer9709-61%E2%80%9380  

[4] https://www.bmedicalsystems.com/en/blog/why-promising-malaria-vaccines-need-a-modern-cold-chain/ 

[5] Statistical report, Malaria Vaccine Pilot Evaluation (MVPE), analysis of data to month 46. https://www.who.int/publications/m/item/statistical-report--malaria-vaccine-pilot-evaluation-(mvpe)--analysis-of-data-to-month-46