What If We Used Mosquitoes To Vaccinate People? Japan Actually Did

The stinging mosquito; the blood-sucking beast; the destroyer of your evening peace; and the silent killer of your midnight sleep. Who knew these pesky little super-spreader of diseases could be transformed into flying vaccine-carrying syringes.

AFP

Turning killers into saviours

The story goes back 11 years ago when a group of Japanese researchers genetically engineered mosquitoes that spread vaccines instead of disease. Now normally when mosquitoes bite, they inject a tiny drop of saliva that prevents your blood from clotting. What this group did was add an antigen--a compound that triggers an immune response--to the mix of proteins in their saliva.

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For their study, the group attached SP15 vaccine against leishmaniasis--a parasitic disease spread by sand flies that can cause skin sores and organ damage--to a malaria mosquito. These mosquitoes produced SP15 in their saliva, the team reported in their paper published in Insect Molecular Biology, and mice bitten by these mosquitoes produced antibodies against the parasite.

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However, the team wasn¡¯t sure whether the immune response was strong enough to protect against infection. In the experiment, mice were bitten some 1,500 times on average; and although that number may seem quite staggering, other studies show that in places where malaria is rampant, people get bitten more than 100 times a night.

¡°Following bites, protective immune responses are induced, just like a conventional vaccination but with no pain and no cost,¡± lead researcher Shigeto Yoshida had said in a statement. ¡°What¡¯s more, continuous exposure to bites will maintain high levels of protective immunity, through natural boosting, for a lifetime. So the insect shifts from being a pest to being beneficial.¡±

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Can we really use mosquitoes to vaccinate humans?

The regulatory and ethical issues may, however, prevent these flying vaccinators from ever taking wing--at least for the delivery of human vaccines. For one, there¡¯s a huge difference in the number of mosquito bites a person receives as compared to someone else; and therefore, people would get vastly different doses of the vaccine. Think of it as like, giving a jab of Covishield to one person and the others getting hundreds of them.

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Secondly, releasing mosquitoes out in the wild also rids people of the choice whether they want to get vaccinated in the first place. However, these ¡®flying syringes¡¯ may have potential in vaccinating animals--they don¡¯t need to sign a consent and the variation in dosage might be less of a concern.

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Scientists have long been dreaming of several ways to tinker with insects' DNA to fight diseases. They¡¯re looking to create a strain of genetically modified mosquitoes that would spread genes that either reduce their population or make them resistant to infections so mosquitoes don¡¯t pass on pathogens to humans. It was only earlier this week that researchers looked to curb malaria by altering a mosquito¡¯s gut genes to make them spread antimalarial genes to the next generation of their species.

With the alarming rise in Covid-19 daily cases, who knows we might need a crazy solution like ¡®flying vaccinators¡¯ after all.