Malaria Vaccine Trial Shows Promising Results
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WHO WELCOMES PROGRESS
Geneva - The World Health Organization (WHO) welcomes the re-
sults of a clinical trial demonstrating that a candidate malaria
vaccine has conferred protection in young children in Africa and
comments as follows:
Dr Marie-Paule Kieny, Director, Initiative for Vaccine Research
(IVR), WHO:
The results of this trial indicate that an effective vaccine
against malaria that could potentially save the lives of mil-
lions of children is possible. While much more work on this vac-
cine is still required, this constitutes a breakthrough in ma-
laria vaccine research.
This step forward also highlights the crucial role that African
governments, research institutions and scientists in the malaria
endemic areas of Africa play in developing tools and strategies
against this major killer of children.
While many candidate malaria vaccines have been developed over
the past 25 years, the RTS,S/AS02A vaccine is the first that has
demonstrated a significant capability to protect human adult
volunteers against an experimental infection with the malaria
parasite. The new results indicate that the vaccine induces pro-
tection against malaria in children one to four years old in Af-
rica.
Although the 57.7% reported vaccine efficacy against severe dis-
ease is less than that of classical childhood vaccines, which is
often greater than 80%, the outcome of the trial is very encour-
aging for the future of malaria vaccines because it is the first
demonstration of any efficacy against severe malaria in chil-
dren.
The partners (see Background below) involved in the clinical
trial participated in the WHO/IVR Malaria Vaccine Advisory Com-
mittee in Montreux, Switzerland on 13 October. Established in
2002, the MALVAC Committee monitors global malaria vaccine de-
velopment, identifies scientific knowledge gaps and new research
areas and convenes funding agencies who support malaria vaccine
development.
Background
The most advanced candidate malaria vaccine, RTS, S/AS02A, was
developed through the partnership of GlaxoSmithKline Biologicals
and the Malaria Vaccine Initiative (MVI) of the Program for Ap-
propriate Technology in Health (PATH). RTS,S/AS02A was tested in
a Phase 2b clinical trial involving 2022 one to four year old
children in Maputo Province, southern Mozambique, from April
2003 to May 2004. The children received three doses of the can-
didate vaccine. The trial site has perennial malaria transmis-
sion mostly due to/ Plasmodium falciparum/, one of the most com-
mon and the most deadly type of malaria infection. The candidate
vaccine delayed the time to new infections with the/ P. falcipa-
rum/ malaria parasite by 45%, reduced the risk of a clinical
episode of malaria by 29.9% and reduced new episodes of severe
malaria by 57.7%.
Over 40% of the world's children live in malaria-endemic coun-
tries. Around 90% of these deaths occur in Africa, mostly in
young children. There are 300-500 million malaria infections
each year globally, resulting in more than one million deaths.
Malaria is Africa's leading cause of under-five mortality. It
kills one African child every 30 seconds. Children who survive
an episode of severe malaria may suffer from learning impair-
ments or brain damage.
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Efficacy of the RTS,S/AS02A vaccine against Plasmodium falcipa-
rum infection and disease in young African children: randomised
controlled trial
Pedro L Alonso et al.
The Lancet Volume 364, Number 9443, 1411-1420, 16 October 2004
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