Researchers in the Milken Institute School of Public Health developed two vaccines using messenger RNA technology that could be the first to limit the infection and transmission of malaria, according to a December release.
Nirbhay Kumar, the lead researcher and a professor in the department of global health, said his teams’ vaccines improved mice’s ability to resist malaria infection and transmission during initial trials, which will hopefully transfer over to humans during the inhuman trials in the next few years. He said the use of mRNA technologies that transcribe DNA into proteins helped researchers develop the vaccine, which produced a 95 percent efficacy rate at limiting transmission during the trials, which is almost 25 percent more efficient than the currently approved malaria vaccine.
Kumar said previous vaccine creation efforts in the last decade stagnated until recent technological advances in vaccine development in the last few years, like the methods used to create the COVID-19 mRNA vaccine, inspired the use of mRNA technologies. He said the proteins in the mRNA vaccine have a high success rate in improving the immune system’s response against malaria-causing P. Falciparum parasites.
“Vaccines are going to be absolutely central to the process of malaria elimination,” Kumar said.
He said the use of a vaccine cocktail, a combination of two vaccines in a single dose, led to the most improved response – blocking infection and transmission during the mice trials. Kumar said he hopes the vaccine will help lead to the eventual elimination of the disease, a goal of researchers for decades.
Kumar said the next step in the trials is to seek funds from the National Institutes of Health to test the safety, toxicity and effectiveness of the vaccines on larger animals before moving the trials onto humans. He said the continued testing on animals and humans could be as fast as two to three years.
“A combination of the two vaccines would be much more effective or likely to be much more effective than a single vaccine alone,” Kumar said.
The World Health Health Organization reported 247 million cases of malaria worldwide in 2021, the most recent year of data, with 95 percent of the cases reported in Africa. Children under five account for 80 percent of malaria-related deaths in Africa, and the continent accounts for 96 percent of all malaria-related deaths, according to the WHO data.
Plasmodium parasites transmitted through the bite of a mosquito cause malaria, a disease characterized by headaches, vomiting and fever. About 2,000 cases of malaria are diagnosed each year in the United States, making up a small fraction of the estimated 247 million cases worldwide in 2021, according to the Centers for Disease Control and Prevention.
Kumar said the R21 vaccine, a shot developed in 2021 that uses a protein to control immune responses, has an efficacy rate 25 percent lower than his team’s vaccines. He says by both targeting infection and transmission, the mRNA vaccine is able to work together at different stages of the parasite’s life to eliminate infection more effectively than the R21 vaccine, which does not incorporate mRNA technology.
The World Health Organization has only approved the RTS, S/AS01 malaria vaccine for children in regions with moderate to high malaria transmission like sub-Saharan Africa in 2021, according to the WHO. GlaxoSmithKline – a global biopharma company – researched and developed the vaccine and found it reduces the risk of death and hospitalization by 70 percent.
“We are proposing to combine a vaccine that targets infection with a vaccine that also targets the transmission of malaria,” Kumar says.
Experts in medicine and biochemistry said the vaccines developed by the GW researchers explore new antigens – foreign substances that induce an immune response in the body – and allow researchers to study their effects on malaria and eventually its effects on humans.
Andrea Berry, an associate professor of pediatrics and medicine at the University of Maryland School of Medicine, said the ever-changing, malaria-causing parasites posed significant challenges to the creation of an effective malaria vaccine. She said the parasite goes through different cycles of life in the body, making it harder to target the disease because the shape and number of proteins can change weekly.
She said mRNA vaccines allow for researchers to experiment with different antigens faster, which can increase vaccine development times. Berry said with the help of vaccines, eradication of malaria needs to be a “concerted effort” with awareness campaigns, foundations and resources.
“If we want to eradicate malaria, we have to have a campaign,” Berry said. “I think the way we just poured our resources into COVID is the way that we might be able to achieve eradication.”
Manuel Llinás, a distinguished professor of biochemistry and molecular biology at Penn State University, said creating a vaccine for malaria has been difficult in the past because scientists are still working to understand the immune response to the disease and how to achieve long-term protection. He said the main defense against malaria that currently exists continues to be antimalarial drugs like Artemisinin, which helps the body to attack malaria-causing parasites.
Llinás said the vaccines with mRNA technologies can withstand transportation, undergo easy modification and immunize patients in concentrated doses, which can mitigate the spread of malaria in areas with a high number of cases.
“It’s in our good conscience to treat infectious diseases that affect not only the wealthy nations but those who are most in need in the endemic and impoverished places of the world,” Llinás said.