There are more than 240 million cases of malaria each year, and this deadly disease kills more than 400,000 people in 60 different countries.
April 25 is World Malaria Day, when the World Health Organization (WHO) raises awareness about the collective struggle for a world free of this disease.
But while the launch of the first WHO-approved malaria vaccine is helping to fight, climate change and warming temperatures are causing the deadly disease to spread to new areas where it has never been seen before. before.
To read especially on BBC Africa:
A deadly spread
“Warmer temperatures increase competition or the ability of mosquitoes to carry the disease-causing malaria parasite,” says Dr. Isabel Fletcher, science data manager for science at the Wellcome Trust.
“Climate change will make more areas of the world more prone to mosquito-borne malaria transmission. As the world warms, malaria can be expected to spread to new mountainous areas, which could now be too cold for transmission, “he warns.
According to the United Nations Intergovernmental Panel on Climate Change (IPCC), even if all the carbon reduction policies put in place by governments by the end of 2020 were fully implemented, the world would warm by 3.2 ° C more this century. . The overall goal is to keep the temperature rise to 1.5 ° C or less by reducing carbon emissions.
Along with rising temperatures, researchers warn that rainfall and humidity, or even drought conditions, can also cause faster growth of malaria-carrying mosquitoes where the disease had not been previously reported.
“Studies have shown in the Caribbean and Brazil that in times of drought people store more water. This creates a good habitat for mosquitoes. Dengue can increase,” says Dr. Fletcher.
There is concern that if this happens with dengue, it will also happen with malaria.
Climate change may also reduce malaria transmission in some areas where conditions are already optimal. That is why Dr. Fletcher believes that a better understanding of the effects of temperature changes will be key to continuing the fight against the disease.
“By creating risk projections for the future, we can identify populations that are at risk and therefore target interventions accordingly,” he says.
What are the symptoms of malaria?
Malaria is a serious infection spread by mosquitoes, which can cause death if left undiagnosed and treated quickly. Symptoms include:
- high temperature, sweating and chills
- headache and feeling of confusion
- feeling very tired and sleepy (especially in children)
- feeling unwell, abdominal pain and diarrhea
- loss of appetite
- muscle aches
- yellow or white skin of the eyes
- sore throat, cough and difficulty breathing
But as climate change threatens to complicate the fight against malaria, new advances have been made against the disease.
The WHO has just announced that more than one million children in Ghana, Kenya and Malawi have now received one or more doses of the world’s first malaria vaccine, thanks to a trial program coordinated by the organization .
Malaria vaccine pilots, first launched by the government of Malawi in April 2019, have shown that the RTS, S / AS01 (RTS, S) vaccine is safe and feasible, and significantly reduces severe malaria death .
It was the first stages of this program that led the WHO to approve its widespread use in sub-Saharan Africa and other areas with moderate to high malaria transmission.
What is the WHO’s strategy to prevent malaria?
The WHO has developed a roadmap to fight the disease. The objectives of the organization are:
- reduce the incidence of malaria by at least 90% by 2030
- reduce malaria mortality rates by at least 90% by 2030
- eliminate malaria in at least 35 countries by 2030
- prevent the resurgence of malaria in all malaria-free countries.
The organization estimates that the vaccine could save the lives of an additional 40,000 to 80,000 African children each year.
“We were able to examine the impact of the vaccine after two years and its safety profile. We found that the vaccine is very safe and well tolerated,” said Dr. Mary Hamel, who runs the program. the WHO malaria vaccine. .
“In those first two years of vaccine use, the impact was spectacular, with a one-third drop in hospital admissions due to severe and life-threatening malaria.”
In addition to RTS, S, there are other candidates for the malaria vaccine. R21 / Matrix-M is among those in initial clinical development.
Pharmaceutical giant BioNTech also aims to develop a malaria vaccine using the same cutting-edge mRNA technology that was first used publicly in its Covid-19 vaccine.
Malaria is a parasite that invades and destroys human blood cells to reproduce. It is transmitted by the bite of blood-sucking mosquitoes.
The existing RTS, S vaccine targets the most deadly and common parasite in Africa: Plasmodium falciparum.
When a victim is bitten by a mosquito, this parasite enters the bloodstream and infects the liver cells. The vaccine is designed to prevent the parasite from infecting the liver, where it can mature, multiply, re-enter the bloodstream, and infect red blood cells, leading to symptoms of disease.
The vaccine requires four doses to be effective, the first three being given one month apart at five, six and seven months of age and a final booster at around 18 months.
Health experts recommend that the vaccine be used in combination with a number of strategies designed to prevent infection and reduce the transmission of disease in the first place.
WHO expects vaccine demand to exceed 80 million doses a year, especially in sub-Saharan Africa.
This high demand poses challenges.
“Supply will be surpassed by demand quite rapidly as the manufacturer increases vaccine production,” says Dr. Hamel.
There is currently only one manufacturer, GlaxoSmithKline (GSK).
“The plan is to increase GSK to 15 million doses per year,” says Dr. Hamel.
“We really need to bring together the commitment and the political will and ensure that there are enough vaccines to reach children at risk for severe malaria.”