Advance administration of antibiotics in residents of areas with high malaria transmission could act as a natural “needle-free” vaccination against the disease, a new study has found.

In the study, led by Dr. Steffen Borrmann from the Department of Infectious Diseases at Heidelberg University Hospital, mice were given an antibiotic for three days and were simultaneously infected with malaria.

And they found that no parasites appeared in the blood and life-threatening disease is averted. In addition, the animals treated in this manner also develop robust, long-term immunity against subsequent infections. The scientists developed the following immunization model on mice. Sporozoites (infectious stage of malaria parasites transmitted by mosquitoes) were injected directly into the animals’ blood. At the same time, mice were treated with the antibiotics clindamycin or azithromycin. Normally, the sporozoites enter the liver, where they replicate massively and mature to the disease-causing blood stage forms (merozoites). The medication did not slow down the maturing of the merozoites in liver cells, but they prevented the red corpuscles in the blood from becoming infected. The typical disease symptoms such as fever and if left untreated, fatal malaria, which are caused solely by the blood stage forms of the parasite, did not occur. The parasites that accumulated in the liver gave the immune system sufficient stimulus to develop robust, long-term immunity. After 40 days, four months, and six months, the researchers again infected the mice with sporozoites, this time without adding antibiotics. All animals had complete protection against malaria. “The antibiotics used are reasonably priced medicines with few and self-limiting side effects. The periodic, prophylactic administration of antibiotics to people in malaria regions has the potential to be used as a “needle-free”, natural vaccination. This would give us an additional powerful tool against malaria,” said Dr. Steffen Borrmann. The study has been published in Science Translational Medicine.