Getting the message from particles to protection

10 June 2025 - Wits University

mRNA vaccine innovations are revolutionising how homegrown life-saving jabs can tackle persistent diseases like TB.

One reason that scientists like Dr Kristie Bloom would painstakingly work with minuscule particles and molecules in labs, over many years, is to create simpler and more swiftly manufactured vaccines that are designed to save lives.

Bloom is working off a long and necessary history—traditionally, vaccines work when a weakened virus, or a piece of the virus’s protein, was injected into a patient to train their immune system to attack the actual virus when it enters their body. These vaccines saved lives, but they take a long time to make.

mRNA: a leap forward in vaccine science

足球竞彩app排名 catapulted the use of messenger ribonucleic acid (mRNA) as a vaccine, galvanising the Wits Antiviral Gene Therapy Research Unit (AGTRU), where Bloom works as a next-generation vaccine team lead.

They leveraged their basic scientific work in RNA therapies and applied it to mRNA vaccines and associated technologies. Once the genetic code of SARS-CoV-2 (the virus that causes 足球竞彩app排名)was established, scientists could speedily design an mRNA.

“The 足球竞彩app排名 pandemic highlighted the need for scalable vaccine platforms, particularly in low- and middle-income countries like South Africa. We quickly prioritised mRNA vaccine development and created a candidate in six months,” says Bloom.

How mRNA vaccines work

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, such as a lipid nanoparticle.

This then instructs your cells to make a harmless piece of the virus or antigen, usually a protein from its surface, like the spike protein in 足球竞彩app排名 vaccines.

When the immune system sees the protein, it recognises it as foreign and mounts an immune response.

The protein is only briefly produced by your own cells. It’s a temporary instruction sheet. If the actual virus ever shows up, the immune system is trained to defeat it.

Made in a lab, without living cells

mRNA can be made quicker than traditional vaccines because it is cell-free and many doses can be made in small manufacturing facilities.

“We also see that the processes mimic how real infection works, potentially leading to stronger and longer-lasting immunity. One of the best parts about this technology is that it is flexible. If a new virus pops up, the mRNA ‘recipe’ can be changed,” says Bloom.

She and her team make mRNA in the AGTRU lab without using living cells. The team does this through in-vitro transcription, using a strand of DNA as the starting point. An enzyme reads this DNA and builds a matching mRNA strand as if copying a recipe onto a note card.

Tackling TB, an ancient enemy

As mRNA is so adaptable, it is a significant game changer in fighting disease. This is where Bloom’s passion and expertise meet. AGTRU is using mRNA technology to create a prophylactic vaccine in the fight against tuberculosis.

The infectious airborne pathogen, Mycobacterium tuberculosis, has been around for about 9000 years, and is still a thorn in the side of infectious disease experts. While the traditional BCG vaccine for TB is administered to infants as a preventative measure, protection wanes in adolescence. TB incidence, therefore, remains endemic to South Africa, with TB deaths remaining high.

The World Health Organization (WHO) notes that TB has “catastrophic” costs for affected households. The WHO’s End TB strategy is a blueprint for countries to have 80% fewer new cases of TB, 90% fewer deaths, and to eliminate the suffering of TB-affected households by 2030.

A new partnership for a new solution

A new vaccine is thus urgent and necessary but has felt elusive. AGTRU’s scientists are however hoping to outsmart the M. tuberculosis germ, which cleverly evades the T-cells necessary to fight infection.

AGTRU joined forces with Professor Thomas Scriba and Dr Munyaradzi Musvosvi from the South African Tuberculosis Vaccine Initiative (SATVI) at the University of Cape Town, to create a home-grown vaccine to fight TB, which 56,000 people in South Africa died from in 2023.

“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 prophylactic candidates currently in advanced discovery and product development stages,” says Musvosvi.

The hope and the stakes

SATVI notes that over 25 years, an effective vaccine could prevent up to 76 million TB cases and 8.5 million TB deaths, resulting in US$3.8 billion in treatment costs.

“With our candidate vaccine, we could push the boundaries of what’s possible, including developing and manufacturing the vaccine on South African soil,” says Bloom.