The World Health Organization Endorses the World’s First Malaria Vaccine

Four doses of the vaccine Mosquirix prevents the risk of the mosquito-borne disease by 40 percent

A health worker vaccinating a child against malaria in Kenya. The child is being held by her mother who is smiling.
In 2019 alone, malaria killed 400,000 people, with most individuals residing in sub-Saharan Africa. Children under five are more vulnerable to the detrimental effects of malaria, and most deaths occur within this age group. Joseph Odour/Associated Press

On October 6, the World Health Organization (WHO) announced it is recommending a groundbreaking vaccine for children in countries that have high malaria transmission rates. The drug—dubbed RTS,S or Mosquirix—is the world's first human parasite vaccine and may save tens of thousands of lives each year, reports Apoorva Mandavilli for the New York Times.

The health agency's recommendation follows a successful pilot program in three African countries that inoculated 800,000 children with the vaccine since 2019. The results of the program showed that the vaccine was safe and effective in remote rural areas, Aylin Woodland and Jake Epstein report for Insider.

"Using this vaccine in addition to existing tools to prevent malaria could save tens of thousands of young lives each year," said WHO director-general Tedros Adhanom Ghebreyesus during a press conference.

Malaria is transmitted through a parasite called, Plasmodium falciparum, which is only carried by infected female Anopheles mosquitos. The illness can strike a person more than once. Even when the disease does not result in death, continuous reinfections can weaken and alter the immune system, leaving individuals more vulnerable to other diseases and pathogens, per the New York Times. Children under five are more vulnerable to the detrimental effects of malaria, and most deaths occur within this age group. Repeated infection can affect a child's development, Helen Branswell reports for STAT News.

In 2019 alone, malaria killed 400,000 people, with most individuals residing in sub-Saharan Africa and children under five accounting for as many as 279,000 deaths within that total, STAT reports. In sub-Saharan Africa, malaria is the primary cause of childhood illness and death. On average, more than 260,000 children under the age of five die from the disease annually, per a WHO statement.

The malaria vaccine was first produced in 1987 by GlaxoSmithKline (GSK) and funded by the Bill and Melinda Gates Foundation and PATH, a global health group based in Seattle, the Guardian's Lizzy Davies reports. After 30 years in the making, the vaccine lowers the risk of getting malaria by 40 percent. While its efficacy rate is not as high vaccines for other illnesses, it is still highly effective when combined with other malaria prevention methods.

"It may not sound like much, but we're talking about 40% reduction in severe malaria, which unfortunately still has high mortality even when you have good access to good treatment," said David Schellenberg, a WHO scientific advisor, in an interview with BBC.

While the vaccine isn't perfect, a study published in the New England Journal of Medicine last month found that when used in combination with other preventive treatments, it more effectively prevented severe illness, hospitalization, and death than using any single method alone, especially during seasons of high malaria transmission rates, the New York Times reports.

Based on clinical data, Mosquirix prevents four-in-ten mild-to-moderate malaria cases and three-in-ten cases of severe, life-threatening malaria for at least four years after receiving the vaccine, Insider reports.

The vaccine is administered in four doses. Because four shots are needed for the vaccine to be effective, scientists raised concerns about the practicality of delivering a four-dose regimen in the real world, especially in rural settings, STAT reports. 

Researchers in the pilot study administered all four doses to recipients in Ghana, Kenya, and Malawi. The first three doses were given to children within their first months of life. Many children received their first dose at either five or six months old, and then received the other two doses at monthly intervals thereafter, Insider reports. The children were then inoculated with the final dose around their second birthday. Community demand for the vaccine was strong, and they reached a high number of children, Tedros tells Insider.

Next, the global vaccine alliance (Gavi) will determine if the malaria vaccine is a worthwhile investment, per the New York Times. If the board approves the vaccine, then they will purchase the vaccine for countries that need it.

"It has been a long road, and is extremely exciting to finally be able to say that [the vaccine] could soon be available – alongside other malaria interventions – to more children across Africa," Ashley Birkett, the head of malaria vaccine development at PATH, tells STAT.

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