Immunization, Vaccines and Biologicals

Immunization highlights: 2011

Vaccine research and development

Promising results from clinical trial of advanced malaria vaccine candidate

Anopheles minimus, a malaria vector of the Orient mosquito, as she feeds on a human host
CDC/James Gathany
The complexity of the malaria parasite makes development of a malaria vaccine a very difficult task

First results from a large-scale phase 3 clinical trial of the most advanced malaria vaccine candidate, RTS,S/AS01 announced at the Global Malaria Forum in Seattle in October 2011, show a 55% reduction in the frequency of malaria episodes during the 12 months of follow-up in children 5-17 months of age at first immunization. The phase 3 trial of RTS,S/AS01 includes 15 460 infants in seven sub-Saharan African countries: Burkina Faso, Gabon, Ghana, Kenya, Malawi, Mozambique, and the United Republic of Tanzania. The two age groups participating in the trials are: infants, who have received three doses of the malaria vaccine together with other routine childhood vaccines at 6, 10 and 14 weeks of age, and older children aged 5-17 months at first dose of RTS,S/AS01. While all those involved in the trials are excited by the latest results in the 5-17 month age group, the efficacy of the population in the expected target population of 6-14 weeks is not yet known.

WHO has provided advice to the partnership responsible for the development of RTS,S/AS01 — GlaxoSmithKline Biologicals and the PATH Malaria Vaccine Initiative — since the outset of the vaccine's development. The expert group advising WHO on phase 3 malaria vaccine trials, the Joint Technical Expert Group on Malaria Vaccines, has reviewed the latest results, and will review further results from the trial as they become available. If all required public health information, including safety and efficacy data, from the trial is deemed satisfactory, a WHO recommendation for use could be possible as early as 2015. Governments in Africa often find WHO recommendations helpful for national policy-making.

"Malaria has never had a vaccine get this far. If licensed, it would be the very first human vaccine against a parasitic disease"

Dr Margaret Chan, WHO Director-General during her keynote address to participants at the Global Malaria Forum in Seattle

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