Malaria vaccine: administered by a mosquito bite

Malaria vaccine: administered by a mosquito bite

scientists have a new vaccination strategy against malaria Immunity strengthens by bites of genetically modified mosquitoes. Immunization takes place via insects that are infected with modified versions of the parasite, caused by malaria. In a study, the receipt of the participants was reduced to Malaria, which may be paving the way for more effective methods to combat this disease, which infected around 250 million people annually.

"These results represent a significant progress in the development of malaria vaccines," says Julius Hafalla, immunologist at the London School of Hygiene & Tropical Medicine. "The persistent global malaria pollution makes the development of more effective vaccines a critical priority."

The study was published on November 20 in New England Journal of Medicine . The participants were exposed to bite of mosquitoes that were infected with a modified version of the Falciparum parasites plasmodium, which caused malaria. In humans, the parasites reach the liver, where they infect red blood cells. The parasites were developed so that they stop growing into the human body shortly after the transfer. Almost 90 % of the participants who were exposed to the modified parasites do not suffer from the stings of malaria pieces.

There are two approved Malaria vaccine . Both aim to produce long -term immunity by producing antibodies that prevent malaria parasites from infecting liver cells, as well as breakdown infections.

However, these vaccines only achieve an effectiveness of around 75 % and require refreshing vaccinations. Therefore, immunologists are still looking for alternative strategies.

An approach is to use genetically modified parasites. The research team had previously tested the effectiveness of a modified malaria parasite called GA1, which is designed in such a way that it stops growing in humans about 24 hours after infection 2 . But the GA1 parasite protected only a few participants from Malaria, which caused the team to develop a second parasite, GA2. GA2 is designed in such a way that he stops growing about six days after the infection, in the crucial phase in which the parasites in the human liver cells replicate.

The researchers tested whether exposure to GA1 or GA2 could help people develop immunity against malaria. Participants were exposed to 50 mosquitoes; 10 participants received bites of mosquitoes that were infected with GA1 parasites, and 10 were bitten by mosquitoes with GA2 parasites. Three weeks later, the participants were exposed to mosquitoes that transmit malaria. Shortly before exposure to these mosquitoes, both groups of participants had higher antibody values ​​than before. Only one of eight (13 %) participants bitten by GA1 parasites does not affect malaria, compared to 89 % in the GA2 group. Apart from the itching through the mosquito bites, the side effects were limited.

The researchers are now trying to reproduce their results in a larger study.

The work "should be followed by more extensive studies to confirm the ga2 sustainability of GA2 as a candidate for global malaria control," says Hafalla.

1. Lamers, O. A. C. et al. N. Engl. J. Med. 391, 1913–1923 (2024).

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2. Roestenber, M. et al. Sci. Transl. Med. 12, Eaaz5629 (2020).

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