Mehreen Datoo: From Patient to Pioneer in Malaria Vaccines
By Beth He
Every year, nearly 290 million people worldwide are infected with malaria, a disease characterized by high fever, shaking chills, sweats, and other symptoms. It is caused by a parasite that is most commonly spread to humans through infected mosquitoes. Among this alarmingly high infection number was Mehreen Datoo, who contracted the disease in her early 20s during a visit to Uganda. It took her several months to fully recover even after returning to the UK, and some doctors were concerned that she would not make it. Datoo is now a British infectious disease specialist, but back then, she was just a medical student conducting research on HIV. With her family’s roots tracing back to East Africa, Datoo was familiar with the risks of malaria and even recalled sleeping under bed nets during visits. During her hospital stay, she recalls taking antimalarial drugs that helped, but notes that they were not infallible. Inspired by her experiences, Datoo worked at the University of Oxford’s Jenner Institute alongside Sir Adrian Hill, a professor of vaccinology, and developed a breakthrough malaria vaccine.
R21/Matrix-M is the first malaria vaccine to meet the World Health Organization’s (WHO) target of “75 percent efficacy at preventing the disease.” Approved by the WHO in October 2023, it is only the second vaccine to do so; the first was RTS,S/AS01, developed by GSK in 2021. The Serum Institute of India (SII), the world’s largest vaccine manufacturer, has already produced more than 25 million doses of the vaccine. The first doses have already been delivered to patients in South Sudan and Ivory Coast, and it will reach a total of 15 African countries by the end of 2024. Datoo hopes to specifically aid toddlers and infants who are especially at risk due to malnourishment, weak immune systems, and limited access to antimalarial drugs.
The vaccine focuses on the plasmodium sporozoite, the initial infectious stage during which the malaria parasite enters the body. Early on, it primes the bloodstream by stimulating production of antibodies that can protect against the circumsporozoite protein (CSP) of the malaria parasite. R21/Matrix-M is categorized as a subunit vaccine because it utilizes some components of the sporozoite protein combined with a segment of the hepatitis B virus. Together, these help the body initiate a strong immune response to recognize and fight off the malaria protein before it can cause infection. It must be administered in three doses, each four weeks apart, to children three years or younger. One year later, a booster must also be administered to complete the full vaccination.
In a phase 3 study conducted on over 4,800 young children, R21/Matrix-M was shown to have an efficacy of 78%, as compared to the previously approved RTS,S/AS01 which only had an efficacy of 56%. It is important to note that the complex structure of malaria parasites—with over 5,000 genes—makes it extremely difficult to achieve near 100% efficacy. Furthermore, it is $5 less expensive per dose than the previous vaccine.
Yet, despite these successes, Datoo remains adamant that “there’s a lot of work still to be done.” The vaccine only targets one stage of the malaria parasite’s life cycle. Moreover, beyond just infants, many other vulnerable groups, such as pregnant women, are also at higher risk due to potential birth complications and defects. Nevertheless, Datoo’s work on the R21/Matrix-M vaccine brings us one step closer to eradicating malaria and saving countless lives.
Works Cited
Dawisha, Emile. "Malaria Gamechangers, Part 6: R21 malaria vaccine." United to Beat Malaria, 25 May 2023, beatmalaria.org/blog/malaria-gamechangers-part-6-r21-malaria-vaccine/.
Eckert, Nadine. "New Malaria Vaccine Proven Effective in Phase 3 Study." Medscape, 12 Feb. 2024, www.medscape.com/viewarticle/new-malaria-vaccine-proven-effective-phase-3-study-2024a10002yn?form=fpf.
"Malaria." Mayo Clinic, 9 Feb. 2023, www.mayoclinic.org/diseases-conditions/malaria/symptoms-causes/syc-20351184.
Perlman, Elisabeth. "British doctor nearly killed by malaria helps develop new vaccine." The Times & The Sunday Times, 15 July 2024, www.thetimes.com/uk/healthcare/article/british-doctor-nearly-killed-by-malaria-helps-develop-new-vaccine-c3jx7lgts.
Pope, Carmen. "What is the new Malaria vaccine (R21/Matrix-M)?" Drugs.com, 4 Oct. 2023, www.drugs.com/medical-answers/what-new-malaria-vaccine-3575227/#:~:text=The%20R21%2FMatrix%2DM%20vaccine%20specifically%20targets%20the%20plasmodium%20%27,the%20parasite%20begins%20to%20multiply.
