Approximately half of the world’s population is at risk of malaria. Most malaria cases and deaths occur in sub-Saharan Africa. However, Asia, Latin America, and to a lesser extent the Middle East and parts of Europe are also affected. In 2008, malaria was present in 108 countries and territories.
Specific population risk groups include:
- Young children in stable transmission areas who have not yet developed protective immunity against the most severe forms of the disease. Young children contribute the bulk of malaria deaths worldwide.
- Non-immune pregnant women are at risk as malaria causes high rates of miscarriage (up to 60% in P. falciparum infection) and maternal death rates of 10–50%.
- Semi-immune pregnant women in areas of high transmission. Malaria can result in miscarriage and low birth weight, especially during the first and second pregnancies. An estimated 200 000 infants die annually as a result of malaria infection during pregnancy.
- Semi-immune HIV-infected pregnant women in stable transmission areas are at increased risk of malaria during all pregnancies. Women with malaria infection of the placenta also have a higher risk of passing HIV infection to their newborns.
- People with HIV/AIDS are at increased risk of malaria disease when infected.
- International travellers from non-endemic areas are at high risk of malaria and its consequences because they lack immunity.
- Immigrants from endemic areas and their children living in non-endemic areas and returning to their home countries to visit friends and relatives are similarly at risk because of waning or absent immunity.
