How cashew nut shells could help Africa make vaccines
- Beth Amato
Waste to wonder: Chemists and scientists are engineering a next-generation vaccine from a surprising and humble source.
As the US pulls the funding rug out from under African countries fighting infectious diseases, it is more necessary than ever for Africa to make its own medicine.
Health inequity began long before 2025 and it is more critical now that innovation for accessible healthcare be ‘home-grown’. An unexpected opportunity emanating from this public health crisis comes in the form of the shell of the humble cashew nut, which is widely farmed across Africa. Cashew nut shells are also waste products, so their use for various industrial and medical applications does not compete with any other applications.
How it works
This C-shaped nut and the oil extracted from its discarded shell can easily be converted into hydrogenated cardanol. A few simple synthetic steps are then followed to make ionisable lipids, which can be custom-designed and assembled as lipid nanoparticles to carry encapsulated messenger RNA (mRNA) in a vaccine, triggering an immune response.
This magic trick can be decoded as follows: Instead of giving your body part of a virus, as was done traditionally, you get a small piece of genetic code (mRNA), wrapped up in a protective bubble (in this case, the lipid nanoparticle made from cashew nutshell oil).
This then instructs your cells to produce a harmless piece of the virus or an antigen so that the immune system recognises the protein as foreign and mounts an immune response. The protein is only briefly produced by your own cells. It is a temporary instruction sheet. If the actual virus ever shows up, the immune system is trained to defeat it.
Why mRNA vaccines matter
These mRNA vaccines can be produced more quickly than traditional vaccines because it is cell-free and a large number of doses can be manufactured in small facilities. This is a game-changer for Africa, making it possible for the African Union to achieve its target of producing 60% of the continent’s vaccines regionally by 2040. Currently, Africa produces only 1% of the vaccines it uses and even then, this is still under a foreign patent for which the continent pays enormous licensing fees.
Professor Patrick Arbuthnot, Director of the South African Medical Research Council’s Antiviral Gene Therapy Research Unit (AGTRU) at Wits, says that the pandemic highlighted the need for scalable vaccine platforms, particularly in South Africa. Arbuthnot and his team quickly pivoted their gene therapy research to prioritise mRNA vaccine discovery.
Turning waste into medical gold
Together with the Wits School of Chemistry, the AGTRU secured a R7-million grant to develop vaccine-enabling compounds derived from cashew nutshell liquid.
“Traditional vaccine production is an arduous and time-consuming process. We have discovered that our lipids can be made at a fraction of the price and are as effective as the lipid molecule’s ‘gold standard’ [SM102] used by Moderna in their 足球竞彩app排名 vaccines,” explains Dr Robin Klintworth, a Postdoctoral Fellow in the Wits School of Chemistry.
According to Professor Charles de Koning, the Head of the Wits School of Chemistry, “We see that these lipids can indeed deliver delicate genetic material safely and flexibly. Cashew nutshell oil-derived lipids are made in a more sustainable manner than petrochemical-based lipids currently on the market [such as the SM102] and used in mRNA vaccines. Indeed, some of our ionisable lipids have induced a similar immune response to the Moderna lipid SM102.”
Previously, de Koning and his team of chemists previously found a way to turn the same chemical building block derived from cashew nut shells – hydrogenated cardanol – into a class of compounds known as triazines that filter harmful UV rays from the sun. This could be a potential ingredient in sunscreen products.
mRNA’s expanding frontier
“The beauty of this discovery is that it is flexible – the team can alter the mRNA code to tackle other viruses,” says Arbuthnot.
This is where Dr Kristie Bloom from the AGTRU weighs in. This next-generation vaccine team leader is using mRNA technology to create a prophylactic (disease-preventing) vaccine in the fight against tuberculosis (TB).
“It seems that the pursuit of these next-generation mRNA vaccines, which were previously seen as the poor cousins of vaccinology, may activate the T-cells needed to fight TB. We have two TB prophylactic candidates currently in advanced discovery and product development stages,” she says.
While the BCG vaccine is administered to infants as a preventative measure against TB, protection decreases in adolescence. TB incidence, therefore, remains endemic in South Africa, with TB deaths remaining high. The World Health Organization (WHO) noted that TB has “catastrophic” costs for affected households. The WHO’s End TB strategy is a blueprint for countries to achieve 80% fewer new cases of TB, 90% fewer deaths and to eliminate the suffering of TB-affected households by 2030.
Towards a health-equitable future
A new TB vaccine is urgent and necessary but has been elusive until now.
“The discovery of the discarded cashew nutshell oil and its transformation into ionisable lipids as an important part of the mRNA vaccine delivery system is one of the ways we can strengthen the continent’s future pandemic preparedness and response capabilities. This will enhance the continent’s vaccine sovereignty and ultimately, health security and equity,” says Arbuthnot.
- Beth Amato is a freelance writer.
- This article first appeared in?Curiosity,?a research magazine produced by?Wits Communications?and the?Research Office.
- Read more in the 19th issue, themed #Disruption, which explores the crises, tech, research, and people shaking up our world in 2025.