A second malaria vaccine has been approved by the World Health Organization (WHO) in an effort to shield children from the deadly illness that claimed 619,000 lives in 2021.
The R21 vaccine is expected to be less expensive per dose and simpler to produce than the first malaria vaccine approved, RTS,S, according to researchers.
The London School of Hygiene and Tropical Medicine’s Jackie Cook, a malaria researcher, predicts that there will be sufficient to genuinely distribute to children.
R21 was found to be 75% effective in preventing malaria in a trial involving 4,800 children who were administered three doses prior to the onset of the seasonal malaria peak. After a year, a booster dose continued to provide protection. Data from the phase III trial, which was carried out in Tanzania, Kenya, Mali, and Burkina Faso, were published in a preprint1 on September 26.
At a press conference announcing the endorsement on October 2 in Geneva, Switzerland, epidemiologist Mary Hamel, who oversees WHO’s Malaria Vaccine Implementation Programme, stated, “By adding the vaccine to the current tools that are in place, tens of thousands of children’s lives will be saved every year.” The WHO’s recommendation came after last week’s talks between its Malaria Policy Advisory Group and its Strategic Advisory Group of Experts on Immunization.
The vaccine, which has already received approval in Burkina Faso, Ghana, and Nigeria, will go on sale in mid-2024 for $2–4 per dose. RTS,S costs $9.30 per dose, and the WHO recommended it for use in children in 2021.
More supply
More than 1.7 million children in Ghana, Kenya, and Malawi have received RTS,S, which is manufactured by the London-based pharmaceutical company GSK and marketed under the name Mosquirix, since 2019. However, the vaccine’s supply is limited, making it unable to keep up with the demand to fight the mosquito-borne illness that claims the lives of over 260,000 African children under the age of five every year.
The Serum Institute of India in Pune, which claims to have the capacity to produce more than 100 million doses annually, will be responsible for manufacturing the most recent vaccine, a modified version of RTS,S that was developed at the University of Oxford, UK. At the press conference, Kate O’Brien, director of the WHO’s Department of Immunization, Vaccines and Biologicals, based in Baltimore, Maryland, stated, “This is a very big step towards access and full supply to meet the demand.”
In addition, R21 is administered in three doses, with a booster shot 12 months after the third shot. The hepatitis B virus surface antigen and the malaria antigen from the Plasmodium falciparum parasite are combined to create the “scaffold” of both vaccines.
The two antigens have different structures; R21 is more potent and contains five micrograms of the antigen in each dose, whereas RTS,S contains 25 micrograms in a single dose.
Choice of jabs
According to Adrian Hill, a vaccinologist at the University of Oxford who worked on the development of R21, every molecule of R21 has a malaria antigen fused to it, as opposed to one in five molecules in the RTS,S vaccine. This gives R21 a more resilient immune response.
According to Hamel, the two vaccines are equally effective at preventing transmission when administered prior to the peak seasons. However, she continues, “the data to date does not allow us to say that one vaccine performs better than the other.”
Soon, nations will be able to select between the two vaccinations. The biotechnology company Novavax, based in Gaithersburg, Maryland, makes an adjuvant called Matrix-M, which is less expensive and easier to manufacture. According to Hill, this combination will enable the production of 40 times more R21 than RTS,S in the upcoming year.
There are still numerous challenges in the way of eradicating malaria, despite the availability of the two vaccines. Immunization against other diseases is not widely available in certain nations where malaria transmission is particularly high, according to Cook. Making sure it reaches enough kids’ arms to be protective will still be difficult, she continues.
