The outcome of the Phase IIb trial of RTS,S (a vaccine comprising the polypeptides RTS and S) in young Mozambican children consolidated hopes that effective vaccination against malaria is a step nearer, and even elicited a generous promise of commitment from the Chancellor of the Exchequer of the UK. However, it seems that both optimism and generosity should be moderated by the failure of this vaccine to induce meaningful protection against infection by Plasmodium falciparum and that we should await confirmation of its efficacy in diminishing the incidence of severe malaria.
There are still approximately 500 million cases of malaria and 1 million deaths from malaria each year. Yet recently, malaria incidence has been dramatically reduced in some parts of Africa by increasing deployment of anti-mosquito measures and new artemisinin-containing treatments, prompting renewed calls for global eradication. However, treatment and mosquito control currently depend on too few compounds and thus are vulnerable to the emergence of compound-resistant parasites and mosquitoes.
A 20 year-old healthy female volunteer participated in a clinical Phase I and IIa safety and efficacy trial with candidate malaria vaccine PfLSA-3-rec adjuvanted with aluminium hydroxide. Eleven weeks after the third and last immunization she was experimentally infected by bites of Plasmodium falciparum-infected mosquitoes. When the thick blood smear became positive, at day 11, she was treated with artemether/lumefantrine according to protocol. On day 16 post-infection i.e. two days after completion of treatment, she woke up with retrosternal chest pain.
The American Journal of Tropical Medicine and Hygiene
From April 2005 to April 2006, a phase 2 malaria vaccine trial in Kenya enrolled 400 children aged 12-47 months. Each received mixed supervised and unsupervised artemether-lumefantrine for uncomplicated malaria, using a standard six-dose regimen, by weight. Children were followed for detection of parasitemia and clinical malaria. A median of two negative malaria blood films occurred during every recurrent parasitemia (RP) episode, suggesting reinfection over late recrudescence. Median time to RP after starting artemether-lumefantrine was 37 days (36-38).
Antimalarial drugs will be essential tools at all stages of malaria elimination along the path towards eradication, including the early control or "attack" phase to drive down transmission and the later stages of maintaining interruption of transmission, preventing reintroduction of malaria, and eliminating the last residual foci of infection.
In 2009, malaria, a disease transmitted by the bite of an infective Anopheles mosquito, caused an estimated 225 million clinical cases and 781,000 deaths worldwide, of which more than 90% occurred in children aged <5 years in Africa. Approximately half of the world's population, or 3 billion persons, are at risk for acquiring the illness. Malaria is transmitted most intensely in central and western Africa, where in some areas >40% of children aged <10 years are infected and residents can be bitten by more than one infective mosquito every day of the year.
BACKGROUND & OBJECTIVES: With the current snags from the use of Artemisinin - combination therapies (ACTs) in malaria treatment in addition to fear of cross- resistance to unrelated drugs, raising the immunocompetence of individuals in malaria endemic areas by vaccination is the best approach to malaria - free world. METHODS: Water - soluble cationic derivative, N, N, N- trimethylchitosan (TMC) was synthesized from chitosan.
Malaria is an intra-cellular parasitic protozoon responsible for millions of deaths annually. Host and parasite genetic factors are crucial in affecting susceptibility to malaria and progression of the disease. Recent increased deployment of vector controls and new artemisinin combination therapies have dramatically reduced the mortality and morbidity of malaria worldwide. However, the gradual emergence of parasite and mosquito resistance has raised alarm regarding the effectiveness of current artemisinin-based therapies.
Sterile protection against malaria infection can be achieved through vaccination of mice and humans with whole Plasmodium spp. parasites. One such method, known as infection-treatment-vaccination (ITV), involves immunization with wild type sporozoites (spz) under drug coverage.