The development of a malaria vaccine involves the assessment of the efficacy of candidate vaccines through a study called controlled human malaria infection (CHMI). In this type of study, informed willing participants are deliberately infected with the malaria parasite Plasmodium falciparum and such studies have provided invaluable information regarding mechanism of the disease to assist in developing a suitable vaccine. However, current method involving using mosquito bites does not ensure 100% infection success rate in all participants and it restricts the possible number of testing sites.
A novel method which involves inoculating participants with aseptic cryopreserved P. falciparum sporozoites, manufactured by Sanaria who has fellow Malaysian, Dr. Betty Sim Kim Lee as its vice president, could hasten the progress of developing a malaria vaccine. The inoculant, along with the complementary administration regimen, has been shown to be able to infect 100% of the participants. In addition, the amount of sporozoites – one of the stages through which the malarial parasite Plasmodium falciparum undergoes during its life cycle – can be controlled which could not be done if mosquito bites were used. Another advantage is that there is no need for insectary or entomological facilities thus increasing the number of possible sites that CHMI can be conducted.
Malaria is a life-threatening disease and, according to the latest estimates made by the World Health Organisation (WHO), about 627 000 deaths were due to malaria. Approximately half of the world’s population are at risk of contracting malaria but most of the cases of malaria occur in sub-Saharan Africa. It is clear that the inoculant made by Sanaria could potentially aid in relieving the suffering millions of people by expediting the progress of developing malaria vaccine. Even so, before it can be widely used as a routine part of future CHMI studies, the newly made inoculant has to undergo multiple trials in Africa, the US, Europe and, hopefully, Asia. Dr Sim explained that such step needs to be taken to ‘further establish the safety, tolerance level and protective efficacy’. Hopefully, it will be licensed within three to five years. With such a powerful tool, it might not be long before an effective malaria vaccine can finally be developed.
- US-based Malaysian scientist makes major breakthrough – The Malay Mail
- Facts and figures on malaria – WHO
- S. H. Sheehy, A. J. Spencer, A. D. Douglas, B. K. Sim, R. J. Longley, N. J. Edwards, I. D. Poulton, D. Kimani, A. R. Williams, N. A. Anagnostou, R. Roberts, S. Kerridge, M. Voysey, E. R. James, P. F. Billingsley, A. Gunasekera, A. M. Lawrie, S. L. Hoffman, A. V. Hill, PLoS One 2013, 8(6), e65960.
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