Clinical Trial To Test Mosquito Saliva Vaccine For Malaria, Zika And Dengue Viruses
The National Institutes of Health is set to begin the Phase 1 clinical trial of an experimental vaccine aimed to provide protection against mosquito-borne diseases which include Zika, West Nile fever, malaria, and dengue fever.
Thousands Per Year Killed
Mosquito-borne diseases kill thousands of people per year. Malaria, for instance, infected 212 million people and killed more than 438,000 in 2015, according to figures from the World Health Organization.
Other mosquito-transmitted diseases, on the other hand, initially appeared harmless but eventually turned out to cause serious deformities. The Zika virus has recently raised concern particularly to pregnant women as it was tied to birth defects such as microcephaly.
Their prevalence and ability to carry illness-causing viruses and parasites make mosquitoes very deadly despite their size.
"Mosquitoes are one of the deadliest animals in the world. Their ability to carry and spread disease to humans causes millions of deaths every year," the WHO said.
Prevention is better than cure when it comes to mosquito-borne diseases. Researchers have been conducting studies to develop vaccines that could provide protection from mosquito-transmitted pathogens albeit there are still mosquito-borne diseases without commercially available vaccines.
Experimental AGS-v Vaccine
The vaccine called AGS-v works by triggering an immune response to mosquito saliva instead of targeting specific mosquito-transmitted viruses or parasites. The vaccine has four synthetic proteins from the salivary glands of mosquitoes. Such proteins induce antibodies in vaccinated individuals and result in an allergic response that provides vaccinated individuals immunity to infection once bitten by a mosquito carrying disease-causing pathogens.
Up To 60 Volunteers To Participate In The Clinical Trial
The clinical trial will involve up to 60 participants between 18 and 50 years old who will be assigned to any of three groups.
Those in the first group will be administered AGS-v vaccine while those in the second group will get two injections of the vaccine along with an adjuvant — a mixture of oil and water that is usually added to vaccines to boost immune responses. Participants assigned in the third group will get two placebo injections.
The participants will undergo a physical exam and give blood samples between vaccinations and twice after getting the second vaccination to allow investigators to examine their blood samples and measure the levels of antibodies that the vaccination triggered.
After completing the vaccination schedule, the participants will be exposed to mosquitoes that do not carry viruses or parasites. Investigators will then take blood samples to determine if vaccinated participants experience modified response to mosquito bites.
Investigators are also set to conduct a study of the mosquitoes after feeding to evaluate any changes to their life cycle. Researchers think that the mosquitoes that feed on vaccinated participants will experience changes in behavior that may lead to their early death and reduced ability to reproduce, which would indicate that the vaccine has the potential to control mosquito populations and prevent disease transmission.