Mosquitoes as vaccine carriers: a controversial plan to immunise wild bats
They call it “ecological vaccination”, a nod to the One Health dogma that humans are one with Gaia as a living organism. The article says, “both bats and mice exposed to the sterilised vaccine-carrying mosquitoes developed neutralising antibodies against both (rabies and Nipah) diseases.”
The lead Chinese scientist plainly stated, “We want to turn the mosquito into a vaccination tool.” They are clearly thinking about human vaccination.
Mosquitoes usually spread disease, but a Chinese research team proposed flipping that role and using the insects to deliver vaccines to bats. The idea is to reach animals that are hard to treat with conventional methods because they fly, roost in dense colonies and populate inaccessible caves.
The work appears in the journal Science Advances and describes mosquitoes engineered to carry immunisations for both rabies and Nipah viruses inside their saliva. The vaccine platform uses a weakened vesicular stomatitis virus, or VSV, which can infect insects and mammals and is already used in an approved Ebola vaccine made by Merck.
The researchers point out two practical transmission routes: the insect can transfer vaccine when it bites a bat, or the bat can acquire it by eating the insect. Lab experiments showed the vaccine replicates in the mosquito’s salivary glands, creating a biological pathway for delivery.
Vaccinating bats is attractive because they host many dangerous pathogens, from rabies and Nipah to Ebola and various coronaviruses, and human encroachment raises spillover risk. Reaching wild populations with shots is nearly impossible, and mass culling has proven ecologically damaging and counterproductive in some regions.
“Directly targeting bats, the natural reservoirs of these viruses, is crucial to preventing spillover events and mitigating public health risks,” the authors wrote, adding that traditional approaches have largely failed. The paper argues that an ecology-informed method could reduce human and livestock exposures.
To tackle the problem the team developed two delivery options for bat vaccination: vaccine-carrying mosquitoes and an oral route via saline drinking stations that release a salty mist to attract bats. Both approaches were tested in controlled lab settings to assess immune response.
In those experiments, both bats and mice exposed to the sterilised vaccine-carrying mosquitoes developed neutralising antibodies against both diseases. A rabies challenge trial reportedly protected all vaccinated animals from a lethal infection.
The researchers could not run the equivalent lethal test for Nipah because they lacked access to a high-level biosecurity laboratory, but they said antibody levels in vaccinated animals were comparable to those seen for rabies protection. The team also reported that mice and bats consuming the saline vaccine solution developed neutralising antibodies.
“We want to turn the mosquito into a vaccination tool,” Aihua Zheng, a virologist at the Chinese Academy of Sciences and co-author of the report, told NPR. “I’m pretty excited with these result[s].”
Despite the promising lab data, the authors acknowledge the approach is not universally applicable and that “the real work is complicated.” They stress regulatory approvals and environmental safety assessments would be required before any field use.
They add that the platform could be scalable and aimed at conservation goals as well as spillover reduction. “These results demonstrate a flexible, ecology-informed vaccination platform for immunising wild bats, offering a scalable strategy to reduce zoonotic spillover risk while supporting bat conservation,” the authors wrote.
Many outside researchers praised the ingenuity but voiced doubts about practicality, long-term immunity and unintended effects such as continued viral shedding by non-ill but infected bats. There are also geopolitical and funding hurdles that could block development and deployment.
“Technically, it’s very innovative and impressive, no doubt about that,” Prof Dr Edward Holmes, an evolutionary biologist and virologist at the University of Sydney, told The Telegraph. “My main issue is that there are just so many bat viruses, at such high prevalence, and with such dynamic transmission that I have doubts that it could ever work in nature.
He added: “Also, I strongly argue that the real issue is not bats, which have had these viruses from aeons – in reality very few transmit directly [to] humans. But the way humans have disrupted bat habitats and massively increased zoonotic risk, through fur farms and the wildlife trade. Lower tech solutions… would have more impact.”