Immunity protein shots may protect against malaria for months

A single injection that can provide months of protection against malaria has proven effective and safe in small early clinical trials in adults.

Shots containing monoclonal antibodies are aimed primarily at infants and children in countries with the highest malaria infections, the team that conducted the trial said. These young children are most at risk of dying from severe malaria.

In clinical trials, 15 of 17 participants People who received monoclonal antibodies were not infected After being exposed to malaria-infected mosquitoes in a lab, researchers will report on Aug. New England Journal of MedicineAll six people who were not given the drug developed infections.

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In clinical trials, different doses were tested and the drug was administered intravenously or by injection. Based on computer models showing how drugs are taken up, distributed, and eliminated from the body, the researchers estimate that one injection could prevent him from malaria for six months. increase.

“What we were always looking for was some kind of intervention that would prevent transmission reliably and for as long as possible,” says a pediatric infectious disease physician and director of the University of Maryland’s Malaria Research Program. Miriam Laufer says. medical school in Baltimore.

Ideally, it would be a highly effective vaccine that provides years of protection. new malaria vaccine has recently become available, but offers only modest protection against this disease and its protection declines rapidly (SN: 12/22/21). Four doses of the vaccine are required.

Monoclonal antibodies may offer an option that requires only one injection per year. More research is needed to confirm how effective the antibodies are against malaria outside the laboratory and how cost-effective injections are.

Laufer, who was not involved in the study, said injected monoclonal antibodies do not preclude the need for other preventive strategies. However, it is “one of the simpler interventions in terms of minimizing contact with the health system, and may have good benefits.”

What’s fascinating is that “the possibility of giving injections to children, even the youngest ones,” she says. [of] An off-the-shelf antibody that lasts more than 6 months and protects during the rainy season. “His single injection this season will help in West African countries where malaria transmission occurs only during the rainy season.

In 2020, an estimated 241 million people were infected with malaria, resulting in 627,000 deaths worldwide. Most of these deaths occurred in children under the age of five in sub-Saharan Africa. Severe malaria causes death.

To reduce the spread of malaria, measures to control mosquitoes, such as using insecticide-treated bed nets over beds and spraying indoors to kill mosquitoes, and regular use of antimalarial drugs. This includes measures to prevent infection, such as taking In October 2021, the World Health Organization also recommended a new vaccine. In clinical trials, he had a 36% reduction in cases of malaria and severe malaria after four years of follow-up.

A monoclonal antibody is a laboratory-made version of an antibody, a protein produced by the immune system in response to a vaccine or natural infection. Monoclonal means that it contains a clone or copy of a specific antibody.

Antibodies evaluated in clinical trials attach to proteins on the surface of sporozoites (the forms of the malaria parasite that enter the body after being bitten by an infected mosquito) and block the parasite from infecting the liver. .

The new monoclonal antibody is an improvement over previous versions developed by the same research team. The new version binds more tightly to the target Plasmodium protein. It is also regulated so that it does not break down rapidly in the body. This shortens the blood half-life (the time it takes for half of the drug to break down) to 56 days, almost triple that of the previous product.

Two clinical trials are planned to evaluate how effectively the drug protects children in areas where malaria is endemic. One of his trials in Mali, where malaria transmission is seasonal, will study the efficacy of injections over seven months. Another trial in Kenya, one of the East African countries where malaria is endemic year-round, will follow children for a year to assess how well the injections work. can also help determine the optimal dosage for children.