(CTN News) _ Anopheles Malaria Vaccine mosquitoes (called malaria vectors) transmit malaria by biting people, which introduces the parasites present in their saliva – sporozoites – into their bloodstream.
In severe cases, untreated fever, headache, chills, and vomiting can lead to coma or death.
In many parts of Africa, Asia, and the Americas, malaria is prevalent in tropical and subtropical regions around the equator.
There were 241 million malaria cases and 627,000 deaths worldwide in 2021, an increase of 14 million cases and 69,000 deaths over the previous year. 80% of the deaths are caused by pregnant women and children under five.
A vaccine inducing an early immune response
Genetically modified malaria mosquito parasites may be used for creating Malaria Vaccine (through targeted gene deletions), thus containing the entire infectious agent (parasite) in attenuated form.
Using CRISPR, researchers can cut parts of DNA coding for dysfunctional or disease-inducing genes.
PfGAP3KO was created by deleting P52, P36 and SAP1 genes from parasites.
As a result of three deletions, the parasite cannot replicate in the liver or enter red blood cells.
Mosquitoes instead of syringes
In order to create an injectable Malaria Vaccine, the scientists used mosquitoes infected with PfGAP3KO to vaccinate the 26 study participants.
About 200 mosquito bites were given over three or five immunization phases.
50% of the 26 volunteers did not develop blood-stage infections after being exposed to mosquitoes carrying unmodified parasites.
A subset of these individuals were exposed a second time six months later and remained partially protected.
It is believed that live vaccines of this type will produce better protection than those based on single proteins, like the RTS,S malaria vaccine approved by the WHO in 2021, but only 30-40% effective.
In fact, the PfGAP3KO vaccine stimulates broader and more protective immune responses.
In a press release, Dr. Ashley Vaughan, assistant professor of pediatrics at the University of Washington School of Medicine, explains: RTS,S is a subunit vaccine,
So the immune system responds to one antigen, whereas our vaccine expresses thousands of antigens due to its genetically attenuated live parasite. It’s more likely to be protective because it responds to so many antigens. “.
An even more protective immune response would be stimulated by this vaccine.
Attenuated infectious agents with a higher initial dose would provide longer-lasting protection.