Written by Naina Mahajan, a grade 6 student.

The World Health Organization has approved the world’s first vaccine against malaria. This is really good news because Malaria causes severe illness and death in children.

• It’s called the RTS,S/AS01 malaria vaccine
• The disease kills more than 400,000 people a year, most of these are African children.
• It’s made by a pharmaceutical company called GSK
• The vaccine acts against one of five (and the most deadly) malaria parasite species

How bad is the Malaria problem?

GSK says that every two minutes, a child dies of malaria. And more than half of malaria deaths in the world happen in six sub-Saharan African countries – most in Nigeria.

What happens when you get a mosquito bite?

When you get a mosquito bite, the mosquito pierces your skin with a special mouthpart called the “proboscis”. As the mosquito feeds (sucking on your blood), it injects saliva into your skin. This causes a reaction in your body, which mostly results in a bump and itching.

While most mosquito bites are innocuous, some of them carry pathogens, like bacteria and viruses. If you are bitten by a mosquito that carries harmful pathogens, you could get a deadly disease.

Compounds in a mosquito’s saliva react with your body’s initial immune response. The compounds in the saliva help pathogens evade the body’s defenses. Studies have uncovered the fact that animals that have antibodies to the proteins in mosquito saliva have some amount of protection against mosquito-borne diseases.

Vaccines against mosquitoes

There are vaccines that are in the process of being studied for some individual mosquito-borne diseases (like malaria, West Nile virus, and dengue fever), scientists are also trying to develop a vaccine for overall protection against mosquito saliva. This could provide a broader umbrella of protection against many diseases.

An investigation…

To investigate this, Drs Jessica Manning and Matthew Memoli led a research team at the NIH’s (the National Institutes of Health) National Institute of Allergy and Infectious Diseases (NIAID). They tested out a “universal mosquito vaccine” with the name AGS-v. This vaccine contains four synthetic peptides (Peptides are a short chain of amino acids. Amino acids are the chemicals that combine to form proteins.) that are found in the saliva of multiple different mosquito species.

…And a test

Naturally, before any vaccine is made available to the masses, it must be tested. And so, it was with the AGS-v. Forty-nine healthy human volunteers were assigned randomly to any one of three different groups.

Group one received placebo (fake) injections of sterile water; group two received the proper vaccine injections, and group three received the vaccine along with a compound designed to improve immune responses. They were given two injections each, 21 days from one to the next.

The 42^nd day of the study dawned. The volunteers had to undergo a “feeding session”. Disease-free mosquitoes had been specially bred at the NIH and were allowed to feed briefly from the volunteers’ arms, albeit through a fine mesh, while being kept in a cup-like container.

The volunteers were subsequently monitored for twelve months after they received the first vaccination. No one had any serious adverse reactions to the vaccine or the mosquito feeding. After the feeding session, the mosquitoes were also monitored to see whether the vaccine had caused any impact on their survival and the number of offspring they produced.

Results

To test volunteers, scientists normally conduct blood tests. In the volunteers’ blood tests, the results showed that the ones who were in the third group, those who had gotten the vaccine mixed with the compound, produced antibodies specific to the peptides. While one of the volunteers developed a significant rash, after the first dose, no larger side effects were identified. The mosquitoes seemed to remain unaffected after feeding on the vaccinated volunteers.

One of the leaders of the study, Dr. Jessica Manning says this: “A widely available ‘universal’ vaccine could possibly provide protection against emerging and re-emerging mosquito-borne diseases as they arise, allowing public health officials to quickly respond to new outbreaks and epidemics without waiting for new treatments or vaccines to be developed.”

Scientists still need to conduct more research to see whether this vaccine could possibly work against individual pathogens and with exposure to mosquitoes in a natural environment.

Hopefully, though, the vaccine will be effective enough to stop the itching of a mosquito bite and for reducing the severity of mosquito-borne diseases.

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