British scientists have developed vaccine technology that can prevent malaria with just a single dose. Existing vaccines require 2 to 3 doses. In countries with inadequate medical infrastructure, it is often difficult to adhere to vaccination schedules, so a vaccine that only requires one injection is expected to have a greater impact on malaria prevention.
Professor Romain Guyon’s research team at the University of Oxford announced on the 26th that they have developed a vaccine platform that manufactures microcapsules based on microfluidic chips. The research findings were published in the international journal "Science Translational Medicine."
Malaria causes more than 600,000 deaths annually, particularly in underdeveloped regions including Africa. A significant number of the deceased are children. Although vaccines have been developed since the 1940s to combat malaria, only two vaccines have been approved by the World Health Organization (WHO), GlaxoSmithKline's "Mosquirix" and Oxford University's "R21," which were approved in 2021 and 2023, respectively.
Both vaccines are made from proteins (antigens) of the parasite that causes malaria. However, there are limitations with these vaccines. First, Mosquirix requires a minimum of 3 doses, with a malaria prevention effectiveness of only 39%, well below the WHO standard of 75%. Mass production has also been difficult.
R21 has a prevention effectiveness of 77% by adding Novavax's immune booster Matrix-M to the parasite protein, and it can also be mass-produced, but it still requires 2 to 3 doses. There is a problem where its effectiveness diminishes in low-vaccination-rate underdeveloped countries.
The researchers have developed a vaccine platform that can provide additional immune effects with a single dose. The key technology involves encapsulating the vaccine in microcapsules made from a biodegradable polymer called PLGA. When the vaccine is administered, injecting the microcapsules simultaneously causes the initially injected vaccine to trigger an immune response, and after a predetermined time, the capsules release additional vaccine for a secondary vaccination effect.
In animal experiments, the new vaccine achieved a prevention effectiveness of 85%, similar to the existing 2-dose method, with just one injection. Antibody levels were also maintained for up to 11 weeks, which was similar to the levels seen in the existing 2-dose group.
The new vaccine platform is also suitable for refrigeration. The researchers measured effectiveness after refrigerating the vaccine at 4 degrees Celsius for 4 to 7 weeks. The results showed that the immune effect was maintained even after refrigeration. The microcapsules have a diameter of 65 µm (micrometers; 1 µm is one-millionth of a meter) and can be injected with a standard syringe.
The researchers believe that the new vaccine platform will significantly contribute to preventing malaria in underdeveloped regions. They noted that it can be mass-produced and can be applied with only slight modifications to existing vaccine production technologies, adding that "it can induce effective immunity against malaria with just one injection, which could improve vaccination rates and reduce the logistical burdens of vaccine distribution."
The researchers plan to further confirm the safety of the vaccine platform through clinical trials involving humans in the future.
References
Science Translational Medicine (2025), DOI : https://doi.org/10.1126/scitranslmed.adw2256