The scientists identified three popular potato varieties grown in Kenya –Shangi, Sherekea, and Wanjiku – which can carry the cholera vaccine.Imagine biting into a potato and getting vaccinated. No needles, no
pills, just immunity served on a plate.
That is exactly what scientists
from three Kenyan universities have proposed – turning
commonly-consumed potatoes into edible cholera vaccines.
The process involves inserting
into the potato plant’s DNA a special bacteria that carries the vaccine gene.
The potato plant then grows with the vaccine built in.
They detailed this approach in
their paper “Engineering local Kenyan Irish potato varieties as
carriers for edible cholera vaccines” published in Discover Plant, on June 2.
The Kenyan experts said such potatoes
could radically transform vaccine accessibility in remote and poor parts of Kenya.
They identified
three popular potato varieties grown in Kenya –Shangi, Sherekea, and Wanjiku –preferred because of their “high
yield, consumer preference, and suitability for genetic transformation.”
Shangi, for instance, matures quickly and has a high yield, making it ideal
for large-scale production.
Cholera is caused by the bacterium Vibrio cholerae, and can be prevented through an oral
vaccine which must be stored under certain temperature levels.
This cold chain storage requirement
makes vaccines hard to deliver to remote or rural areas without reliable
electricity.
Starting February this year, at least 244 cases of cholera and 11 deaths have been
reported in Kenya, according
to the Ministry of Health.
“Existing traditional
vaccines are costly to manufacture and require specialised cold-chain storage,
alongside transportation and distribution systems, which may not be readily
available facilities especially in limited-resource settings,” the scientists
explained.
They are Beenzu Siamalube
and Emmanuel Ehinmitan from Pan African University; Maina Ngotho and Justus
Onguso of the Jomo Kenyatta University of Agriculture and Technology; and Steven
Runo from Kenyatta University.
So why potatoes? Aside from being a common food, they offer unique advantages. “Potatoes can be
cultivated on a large scale with minimal additional investment,” the experts said.
They referenced earlier studies, including
one from 2005 where humans consumed genetically engineered potatoes expressing
a hepatitis B antigen.
The results showed that 62.5
per cent of participants who consumed three doses developed increased
immunity. “This study demonstrated the potential of plant-based oral vaccines
to boost immunity in individuals previously vaccinated,” the authors write.
Still, turning potatoes
into syringeless immunisation
is not without challenges.
Since potatoes are
typically cooked before eating, there is a risk that heat might degrade the vaccine. “Cooking can
degrade some of the antigenic proteins,” they noted.
Another obstacle is public perception. “Public skepticism toward genetically
modified organisms (GMOs) further complicates their acceptance, particularly
for vaccines intended for direct consumption.” The authors suggest that science
communication and stakeholder engagement will be essential in building trust.
Regulatory concerns also loom large. In Kenya, the use of GM crops is
governed by the National Biosafety Authority. The study calls for “developing
regional or national regulatory guidelines specific to plant-derived
biologics,” alongside robust safety testing like allergenicity and gene flow
analysis.
Despite these hurdles, the promise is too great to ignore. “By harnessing
the power of molecular farming, scientists can produce vaccines and therapeutic
proteins in potatoes, offering a near-user-site alternative to traditional
production methods,” the researchers emphasise.
They said genetically
engineered potatoes could even carry vaccines for other diseases such as malaria and ebola. They even propose
integrating these edible vaccines into “school feeding programmes” to ensure wide access.
However,
their paper only offers a detailed conceptual and methodological framework, but
no experimental or proof-of-concept studies on the same have been done in
Kenya.
As of now,
no plant-based edible vaccines have been approved for public use in humans globally.