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.
