Malaria: stay informed

Health

What is malaria?
Malaria is an acute febrile illness caused by the Plasmodium parasite; it is transmitted to humans through the bites of infected female Anopheles mosquitoes. It is a preventable disease that can be cured.

Who is at risk of malaria?
Nearly half of the world's population is exposed to the risk of malaria. In 2021, an estimated 247 million people contracted the disease in 85 countries. That same year, malaria claimed approximately 619,000 lives.

Some people are more likely to get a severe form of malaria than others. Infants and children under five, pregnant women and people with HIV/AIDS are particularly at risk. Other vulnerable groups include people who travel to areas of intense transmission without having developed partial immunity from prolonged exposure or who are not on chemo-preventive treatment, such as migrants, mobile populations and travellers.

Some people living in areas where malaria is common will develop partial immunity. Although partial immunity never confers complete protection, it reduces the risk that infection will lead to a severe form of the disease. This is why most malaria deaths in Africa occur in young children, while in areas of low transmission where the population has low immunity, all age groups are at risk.

Where is malaria most prevalent?
Malaria mainly occurs in tropical and subtropical countries. The vast majority of malaria cases and deaths from the disease occur in the WHO African Region, most of them caused by the Plasmodium falciparum parasite. This parasite also predominates in other areas with high malaria prevalence, including the South-East Asia Region, the Eastern Mediterranean Region and the Western Pacific Region. In the WHO Region of the Americas, the parasite Plasmodium vivax, responsible for 75% of malaria cases, is the predominant parasite.

The risk of malaria is highest in sub-Saharan Africa; in 2020, almost half of all malaria deaths globally were concentrated in 4 countries in this region – Nigeria (26.6%), Democratic Republic of Congo (12.3%), Uganda (5.1% ) and Mozambique (4.1%).

Is it dangerous to travel to areas where malaria is endemic?
People who are not partially immunized against malaria are at increased risk of contracting the disease. This includes travelers from non-endemic countries going to areas of high transmission as well as people who live in endemic countries but in areas where there is little or no transmission.

As symptoms usually do not appear for 10 to 15 days after infection, travelers are likely to return to their country of origin before showing signs of illness. Physicians in non-endemic areas may fail to recognize symptoms, which can lead to delays in diagnosis and treatment with life-threatening consequences. Also, effective antimalarial drugs are not necessarily licensed or available in all countries.

Chemoprophylaxis can be used as a preventive treatment before traveling to an endemic area. Combined with the use of insecticide-treated bed nets and repeated application of a topical repellent to prevent mosquito bites, chemoprophylaxis significantly reduces the risk of infection. In the event of an infection, a person who has used a given drug as part of chemoprophylaxis should not take the same drug as treatment.

Prior to departure, travelers are encouraged to consult a physician or their National Center for Disease Control to determine appropriate preventative measures.

How to prevent malaria?
Malaria is a preventable disease.

1. Vector control. Vector control is the main strategy used to prevent malaria and reduce its transmission. Two methods of vector control are effective in protecting people living in countries where malaria is endemic: the use of insecticide-treated bed nets, which protect people from mosquito bites while they sleep and kill mosquitoes trying to feed, and indoor residual spraying, which involves applying insecticide to mosquito resting surfaces – interior walls, eaves, house ceilings and other structures servants. The use of insecticide-treated bed nets is the most practical vector control intervention for travellers. WHO maintains a list of vector control products that have been proven to be safe, effective and of good quality.

Is there a vaccine against malaria?

The RTS,S/AS01 (RTS,S) malaria vaccine is the first and, to date, only vaccine proven to be effective in significantly reducing cases of malaria in young children living in areas of moderate transmission to high. It works against Plasmodium falciparum, the deadliest malaria parasite in the world and the most prevalent in Africa.

In 2019, Ghana, Kenya and Malawi began introducing the vaccine in selected areas under a large-scale pilot program coordinated by WHO. To date, the program has demonstrated that the RTS,S vaccine is safe, effective and feasible as part of routine immunization services. By March 2023, more than 1.3 million children had received at least 1 dose of vaccine through this program. Twenty-nine countries in Africa have expressed interest in adopting the malaria vaccine as part of their national malaria control strategies.

What is the difference between malaria elimination and malaria eradication?

Malaria elimination refers to the interruption of transmission in a given geographical area, usually a country. Malaria eradication refers to the complete interruption of malaria transmission globally, in all countries.