Carolina Reid and nine other volunteers waited to participate in a clinical study for a brand-new, experimental malaria vaccine one morning in Seattle.
Reid was next to go. She placed her arm over a cardboard box that contained 200 mosquitoes and was wrapped in mesh, which prevents them from escaping but still permits bites. She remembers it as “literally a Chinese food takeaway container.” The scientist then draped a dark cloth over her arm since nighttime is when mosquitoes like to bite.
The feeding frenzy then started.
Reid claims, “My entire forearm swelled and blistered.” “My family was laughing and asking you why you were doing this to yourself?” She also did it repeatedly. Five times she did it.
You could be thinking, “Surely this is a joke,”
Yet it isn’t. Dr. Sean Murphy, a physician and scientist at the University of Washington in Seattle, is the primary author of a report published on August 24 in Science Translational Medicine that describes the vaccination trials. He says, “We use the mosquitoes like they’re 1,000 miniature flying syringes.”
The parasitic insects transmit live Plasmodium parasites that cause malaria but are genetically altered to not infect humans. In order to be ready to combat the true parasite, the body continues to produce antibodies against the weak parasite.
To be clear, Murphy has no intention of immunizing countless numbers of people via mosquitoes. Although it is uncommon, mosquitoes have occasionally been employed to deliver malaria vaccinations for clinical studies.
Because it is expensive and time-consuming to design a formulation of a parasite that can be administered with a needle, he and his colleagues chose this course of action. It makes logical to utilize mosquitoes for delivery at this proof-of-concept stage, or early stage trials, because the parasites develop inside of them.
According to Dr. Kirsten Lyke, a doctor and vaccine researcher at the University of Maryland School of Medicine who was not involved in the trial, “They went old school with this one.” Everything old may be made new again.
For the creation of vaccines, she deems the use of a genetically altered living parasite “a huge game changer.”
Of course, this particular vaccination is not yet suitable for widespread use. However, the tiny research with 26 people did demonstrate that some subjects were temporarily shielded against malaria by the modified parasites.
The RTS,S vaccine developed by pharmaceutical company GlaxoSmithKline, according to Murphy, was the world’s first malaria vaccine and might eventually be significantly outperformed by this strategy. It was authorized by the World Health Organization last year, but only has a 30–40% effectiveness rate.
Malaria and mosquitoes have a negative association.
Reid joined the trial in 2018, searching for employment. She claims that the $4,100 reward for participation was what initially drew her attention. She discovered a new reason, though, after speaking with friends who had fallen ill with malaria. She claimed that although the money was still wonderful, at that time it was more about taking part in significant study than it was about the money.
Anopheles mosquitoes have salivary glands that are home to malaria parasites. In Africa, where the warm temperature favors the parasite’s development, the sickness is most prevalent. Malaria is spread via the bite of an infected mosquito. The malaria parasite can be transmitted by infected individuals to mosquitoes that bite them, continuing the cycle of infection.
Nations use mosquito nets, insecticides, anti-malarial medications, and even release genetically altered mosquitoes that are unable to bite or lay eggs in an effort to combat malaria.
Scientists estimate that despite these precautions, there are still over 240 million cases of malaria each year and over 600,000 fatalities, which is why immunizations are required.
A good beginning, yet there is still potential for development
Because it employs a complete, weakened parasite instead of the WHO-approved RTS,S vaccine, Murphy believes this experimental vaccination should elicit a stronger immune response. RTS,S, according to him, targets “only one out of more than 5,000 proteins” the parasite makes.
Others have tried to use deactivated parasites to create a malaria vaccine. The disarming was carried out by this researchers using CRISPR, a highly developed set of molecular scissors that can cut DNA, which is novel.
Reid and the other volunteers had to endure a second round of mosquito bites, but this time they carried the actual malaria parasite, to see how well the strategy worked.
Reid was one of seven volunteers that contracted malaria out of the 14 who were exposed to the illness, making the vaccination just 50% effective. Protection didn’t last more than a few months for the other seven.
Reid adds, “I really sobbed when they informed me I had malaria since I grew so close to the nurses.” She wanted to stay in the trials, but her sickness disqualified her. She received a medication to treat her malaria and was then sent home.
The study’s author and a parasitologist at the University of Washington Seattle and Seattle Children’s Research Institute, Stefan Kappe, adds, “We think we can clearly do better.” By administering the vaccine using syringes rather than mosquitoes so they can precisely control the dosage, he and Murphy expect to increase the effectiveness of their team’s vaccine. Greater protection for a longer length of time could result from a bigger initial dosage.
According to Lyke, some researchers believe that employing a parasite that is a little bit more developed than the one in this vaccine might allow the body more time to create an immune response. According to Kappe, the team is already working on such strategy.
There are other issues to think about if next trials show promise. How much would this kind of vaccination cost, to begin with? To create the modified parasites, the researchers are collaborating with a little business named Sanaria. According to Kappe, investment will be needed to scale up manufacturing through boosting production capabilities.
Reid’s experience was so satisfying that she later took part in clinical trials for the Moderna COVID-19 vaccine and a bird flu vaccination. She claims that “for the rest of my life literally,” she will continue to sign up for vaccination research studies.