Can a new vaccine eliminate malaria in Africa? | News

After decades of research and trials, a ground-breaking malaria vaccine has been rolled out across West Africa in a major effort to eradicate the disease, the second leading cause of child death on the continent. .

On January 22, health workers in Cameroon began recruiting infants and children under five for their first dose of the RTS,S vaccine, developed by pharmaceutical giant GlaxoSmithKline (GSK) and non-profit health organization PATH. Ta. The name of the vaccine – RTS,S – refers to the gene of the parasite for which it was produced.

Children in Burkina Faso will be next to receive the jab starting this month. The second vaccine, R21, was approved by the World Health Organization (WHO) in December and is expected to be rolled out within months. The vaccine is already being used in some African countries, led by Ghana. approve first That was last year.

These vaccines were developed as part of a global effort to eliminate malaria, a potentially fatal disease for children and pregnant women. Almost all of the more than 200 million cases of infection worldwide each year occur in African countries.

Here's what you need to know about the new malaria vaccine.

How do vaccines work?

Malaria vaccine research has been ongoing since the 1980s, and trials began in 2004, but the RTS,S vaccine WHO recommends It will be certified in 2021 as part of the process towards certification. In July 2022, the WHO officially approved the vaccine for use. The effectiveness rate is 75 percent.

The vaccine, named Mosquirix, is formulated to activate antibodies and target the infectious stage of Plasmodium falciparum, the parasite that causes malaria. This parasite is transmitted through the bite of a female Anopheles mosquito.

In trials conducted in seven African countries between 2009 and 2011, the RTS,S vaccine prevented infants from developing malaria for at least three years after the first vaccination. Over four years, the number of malaria infections among children vaccinated between five and 17 months of age decreased by 39%. Malaria cases were reduced by 27% in people vaccinated between 6 and 12 weeks of age.

In a pilot program launched in Ghana, Malawi and Kenya in 2019, WHO reported that the use of the vaccine reduced malaria deaths by 13 percent among more than 2 million children monitored. did.

R21 (Matrix-M) is the second malaria vaccine approved by WHO in December 2023. It was developed by the University of Oxford and manufactured by the Serum Institute of India. In pilot trials, R21 showed an efficacy rate of 75% over 12 months. There are plans to roll out the jab in Africa alongside the RTS,S vaccine in mid-2024.

Duke University professor Wendy Prudhomme O'Meara told Al Jazeera that the main drawback of the Oxford vaccine is that it requires frequent booster shots.

“The effects wear off within a year.” [and] This makes it very effective for seasonal protection, which we hope will continue as research and development continues. [research and development] “We can improve the malaria pipeline,” O'Meara said. “I think the malaria community understands that this is an important first step, but it's not the end.”

How dangerous is malaria?

Severe malaria can cause complications such as organ failure and death. Malaria is the second leading cause of childhood death in Africa after respiratory diseases, with nearly 500,000 children dying from malaria each year in African countries.

This disease is especially deadly for children. Because children are less likely to have immunity to this disease.

Pregnant women in their second and third trimesters are also particularly susceptible to malaria, as their immunity levels are reduced. People visiting high-transmission areas from malaria-free areas are also vulnerable because they do not have the immunity built up from living in endemic areas.

Millions of malaria cases are recorded each year around the world. In 2022 alone, approximately 249 million infections were recorded in 85 countries, with 608,000 deaths.

Almost all of these (94%) were in African countries.

Why are African countries so vulnerable to malaria?

Many factors, including weather patterns, poor sanitation, and weak public health systems, contribute to the continent bearing nearly all of the world's malaria burden.

In 2022, nearly all of the world's malaria deaths were recorded on the continent. Four countries accounted for almost half of all cases: Nigeria (27%), Democratic Republic of the Congo (12%), Uganda (5%) and Mozambique (4%).

Malaria thrives in the tropics, where climatic conditions allow Anopheles mosquitoes to produce malaria parasites in their saliva, which can then be transmitted to humans when they bite. Soggy, damp areas are favorite breeding grounds for insects. Therefore, malaria infection rates tend to be higher during the rainy season.

Some analysts describe malaria as a “poor people's disease.” Families who live in mosquito-infested environments and cannot afford chemically treated bed nets or insecticides often bear the brunt of the disease. Treatment for this disease can be expensive. In Mozambique, a 2019 study found that each household needs to spend $3.46 to treat uncomplicated cases, but up to $81.08 to treat severe cases. The average household income in Mozambique is approximately $149 per month.

Duke University's O'Meara said malaria could be eradicated even without a vaccine if more attention was paid to reducing poverty structures and providing better living conditions.

“Before modern insecticide-treated nets were used, before DDT, malaria was eradicated in the United States. [insecticide] And definitely before artemisinin combinations and vaccines. ” she said. “The ecology of malaria in America was of course very different from Africa, but it was still achieved through environmental management and bed nets. [untreated] By reducing human-mosquito contact through better living conditions. Poor housing construction, open windows and eaves, open drainage systems, and poor urban water management contribute significantly to the persistence of malaria. ”

Transmission of malaria also occurs in countries in Asia, the Pacific, and South America, particularly Papua New Guinea. Outside Africa, the disease is spread by female Anopheles mosquitoes, which carry another malaria parasite, Plasmodium vivax, which thrives in cold temperatures.

Which African country has eradicated malaria?

So far, three African countries have successfully eliminated malaria. Mauritius (1973), Algeria (2019) and Cape Verde, which reported zero infections for three consecutive years and was certified malaria-free by the WHO last month.

It took a lot of effort. For example, Cape Verde took decades to obtain WHO certification. In the 1950s, all ten of her islands were affected by malaria. Using targeted pesticide spraying campaigns, the country reported malaria eradication in 1967 and 1983, but many more malaria cases have since been discovered.

Can malaria be eradicated from the world?

It may be possible to eradicate malaria everywhere in the world, but it will not be possible with vaccines alone.

Billionaire philanthropist Bill Gates, who has committed billions of dollars to malaria research through the Bill & Melinda Gates Foundation, says malaria could be eradicated by 2040 based on national eradication goals. We predict that there will be.

The new vaccine is a “major achievement” and a major boost to the global eradication drive, but it won't work on its own, says Target Malaria, an organization working to develop genetically modified mosquitoes to reduce malaria. entomologist Crystal Birungi says. contagion; infection.

“This is an important addition to the toolbox to fight malaria and will save many lives,” Birungi said. “However, research has shown that there is no single cure for malaria, and existing methods such as insecticide sprays, long-lasting insecticide-treated nets, and anti-malarial drugs can be used to develop It remains vitally important that we continue to develop new tools such as genetically modified mosquitoes and gene drives to fight malaria. ”

Many countries are already distributing insecticidal nets, chemicals and preventive oral solutions free of charge to high-risk areas. However, conflict and instability in some countries have hampered those measures, and there are financial and logistical challenges to carrying out widespread and consistent spraying.

Additionally, mosquito behavior is changing. As the world continues to warn about climate change, research shows there will be more breeding grounds for mosquitoes, meaning the transmission of diseases such as malaria could be higher.

Currently, African countries are trying to deal with Anopheles stephensi., An invasive species native to South Asia that thrives in urban environments.

“The mosquito vector is a mosquito that can fly without boundaries, so we need to achieve malaria elimination everywhere to ensure everyone's safety, even in places where malaria has been declared free.” added Birungi.

What happens next with vaccines?

Burkina Faso, which recorded nearly 12.5 million malaria cases in 2022, launched its immunization campaign on February 5, adding RTS,S to other routine vaccines for children. About 250,000 children are being vaccinated in the initial phase because doses are limited.

Children from 5 months of age are eligible to receive 4 scheduled doses. For infants and children in high-risk areas, five doses may be given.

Liberia, Niger and Sierra Leone are next to deploy the jab later this year.

Vaccines are in such high demand that there could be significant supply shortages. Currently, only 18 million doses of the RTS,S vaccine are available to cover 12 countries by 2025, according to the World Health Organization. gabi [full name, organisation, etc?]. It is unclear how many doses will be needed or how large the shortage is, but there are about 207 million children under the age of four across the continent. In total, African countries will need about 40 million to 60 million malaria vaccinations per year by 2026.

There is also the possibility of facing social issues during deployment. In the past, rumors that the vaccine would make women infertile led people to avoid polio shots in countries like Nigeria. Getting the doses to rural and remote areas, as well as finding an adequate electricity supply to store them at the required low temperatures, could be major hurdles to overcome.