In a small early clinical trial in adults, a single injection, which can provide protection against malaria for up to several months, has been shown to be effective and safe.
The team that conducted the trial said the vaccine, which contains monoclonal antibodies, is mainly used in infants and children in countries with the most malaria transmission. These young children are at the highest risk of dying from severe malaria.
In clinical trials, 15 of 17 participants The person receiving the monoclonal antibody is not infected Researchers report Aug. 4 after exposure to malaria mosquitoes in the lab New England Journal of Medicine. All six people who did not receive the drug developed infections.
Clinical trials have tested different doses and administered intravenously or by injection. Based on computer models of how the drug is ingested, distributed and cleared from the body, the researchers estimate that a single shot can prevent malaria for six months.
“We’ve been looking for some kind of intervention that can reliably prevent infection for as long as possible,” said Miriam Laufer, a pediatric infectious disease physician and director of the Malaria Research Program at the University of Maryland School of Medicine in Baltimore.
Ideally, this would be a highly effective vaccine that would provide years of protection, Laufer said.One New Malaria Vaccine Started recently, but it is not very protective against the disease, and the protection is rapidly diminishing (Serial Number: 12/22/21). The vaccine requires four shots.
Monoclonal antibodies can provide an option that requires only one injection per year. More research is needed to understand how well antibodies work against malaria outside the laboratory, and how cost-effective a vaccine is.
Laufer, who was not involved in the new study, said injecting monoclonal antibodies does not rule out the need for other prevention strategies. But it could be “one of the simpler interventions with minimal engagement with the healthcare system, and it has good benefits.”
The appeal, she says, is, “You can give a child, even the youngest, an injection [of] Pre-made antibodies can last six months or more and protect them throughout the rainy season. “The seasonal vaccine is helpful in West African countries, where malaria transmission occurs only during the rainy season.
In 2020, an estimated 241 million people worldwide died from malaria, resulting in 627,000 deaths. Most of these deaths occurred in children under the age of five in sub-Saharan Africa. These youngest children have no chance of developing immunity to the disease and are more likely to contract and die if severe malaria develops.
Reducing malaria transmission includes measures to control mosquitoes, such as using insecticide-treated nets on beds or spraying indoors with insecticides, and preventing infections, such as taking antimalarial drugs regularly. The new vaccine was also recommended by the World Health Organization in October 2021, and after four years of follow-up, it reduced malaria and severe malaria cases by 36% in clinical trials.
Monoclonal antibodies are lab-made versions of antibodies, proteins that the immune system produces in response to a vaccine or natural infection. Monoclonal means that it contains a clone or copy of a specific antibody.
The antibodies evaluated in clinical trials attach to proteins on the surface of sporozoites — a type of Plasmodium parasite that enters the body after an infected mosquito bites it — and prevent the parasite from infecting the liver.
The new monoclonal antibody is an improvement over earlier versions developed by the same research team. The new version binds more strongly to the targeted Plasmodium protein. It also has a tweak that prevents it from degrading too quickly in the body. This increased its half-life in blood (the time it takes for half of the drug to degrade) to 56 days, almost three times as long as its predecessor.
Two clinical trials are planned to evaluate the drug’s protective effect on children in areas where malaria is transmitted. A trial in Mali, where malaria transmission is seasonal, will study the efficacy of the vaccine over seven months. Another trial in Kenya, in the East African country where malaria is perennial, will assess the vaccine’s effectiveness in following children for a year. These studies will also help determine the best dose for children.