PATH | VRL
Menu

Malaria

Every year, malaria kills hundreds of thousands of people, most of them young African children. Malaria can be controlled through the use of medicines, insecticides, and insecticide-treated screens and bednets, and can be treated with antimalarial drugs. Currently, there is no licensed vaccine against malaria; however, several vaccines are under development.

View resources on malaria

On the PATH website

Malaria disease

  • Among the various species of the malaria protozoan parasite, Plasmodium falciparum is the deadliest.
  • Every year, P. falciparum malaria causes the deaths of hundreds of thousands of people, most of them sub-Saharan children younger than five years of age. Malaria also contributes to anemia in children and pregnant women, low birth weight, premature birth, and neurological damage. Hundreds of millions of cases of malaria occur every year.
  • Malaria is transmitted by the female Anopheles mosquito, of which there are more than 40 species. Malaria transmission, which is affected by climate and geography, often coincides with the rainy season.
  • Malaria-control strategies include the use of medicines, insecticides, and insecticide-treated screens and bednets. Control programs led to the elimination of malaria from Australia, Europe, and the United States by the 1950s.
  • Malaria can be treated with a regimen of antimalarial drugs based on the type of infection and status of the patient.

Malaria vaccines

  • No licensed vaccine against malaria currently exists.
  • The malaria vaccine community aims to license—by 2015—a first-generation vaccine that has 50 percent efficacy against severe disease and death, with protection lasting at least one year without the need for boosting.
  • Malaria vaccines in development include: pre-erythrocytic or liver-stage vaccines that aim to protect against the early stage of malaria infection; blood-stage vaccines that aim to reduce the severity of disease; and transmission-blocking vaccines that are intended to prevent mosquitoes that fed on an infected person from spreading malaria to new hosts.
  • The development of malaria vaccines is complex for several reasons:
    • The size and genetic complexity of the parasite mean that each infection presents thousands of antigens to the human immune system. Understanding which of these can be a useful target for vaccine development has been complicated, and to date at least 40 promising antigens have been identified.
    • The parasite changes through several life stages even while in the human host, presenting a different subset of molecules for the immune system to combat at each stage.
    • The parasite has evolved a series of strategies that allow it to confuse, hide, and misdirect the human immune system.
    • It is possible to have multiple malaria infections of different strains at the same time.

References

Page last updated: November 2014.

Photo: PATH/Amy MacIver.