New research has developed a vaccine against malaria using mRNA technology, the same used in some vaccines against Covid-19, and which also uses a mechanism to increase the performance of immune cells in the liver. With organ defense, a break in the disease cycle can occur before it reaches critical stages.
The search for a malaria vaccine has been going on for years. One of them is Mosquirix. It was approved by the World Health Organization (WHO) in 2021 after being developed for 35 years. With an effectiveness of around 50% in the first year after application, the immunizer is indicated for the type of disease most prevalent in Africa – in Brazil, it is not very advantageous.
Another malaria vaccine, this one more powerful, was made by the Oxford University team that created the AstraZeneca vaccine. The vaccine was approved for use in Ghana in April 2023.
There is still mRNA technology, adopted in some vaccines against Covid-19. In this case, a part of the pathogen’s RNA is used to trigger the immune response, without any incorporation into the DNA of the vaccinated living being.
The technology is also studied for the case of malaria and was adopted in the new study published this Thursday (20) in the journal Nature Immunology. The idea of the authors, who are mainly linked to research centers in New Zealand and Australia, was to use mRNA to generate an immune response in people’s livers.
This is because it is in this organ that an important part of the disease cycle takes place in the human body. Caused by protozoa, malaria is transmitted to humans by mosquito bites. After 30 minutes in the body, these parasites enter the liver and stay there for about 15 days. Afterwards, they invade the bloodstream, and symptoms begin to appear, such as fever, headache and chills.
That is, the authors sought ways for the vaccine to generate an immune response concentrated in the liver in order to prevent the completion of the protozoan cycle. To achieve this objective, the focus was given to the T cells present in the tissue of the organ. These cells are an important tool, alongside antibodies, in combating invading microorganisms.
The mRNA model was adopted for the research, but it by itself did not bring very positive results in the generation of liver T cells. So, the scientists set out to add an adjuvant, a substance that enhances the effect of a vaccine, which could boost this immune response concentrated in the organ.
The selected ingredient was already being studied for cell therapy in cases of liver cancer. Through adaptations, he started to compose the vaccine and, then, had a considerable action in generating the T cells of the liver.
There were also no indications that the vaccine is contraindicated for those who have already had malaria, an aspect that is an obstacle in the construction of a drug. “Our vaccine is still capable of generating liver-specific immune cells and providing protection even when animal models were pre-exposed to the disease,” said Lauren Holz, from the University of Melbourne and one of the study’s co-authors, to the study’s disclosure material.
The data are encouraging, but it still takes a long time to confirm that the vaccine will be safe and effective in humans. All tests were pre-clinical, only on animals, and now the scientists intend to evaluate the product in people. This, however, can take years and requires a lot of investment.