COVID-19: UCT math modeller makes her mark

14 April 2021 | Story Nadia Krige. Photo Supplied. Read time 7 min.

In January 2020, the World Health Organization (WHO) invited the University of Cape Town’s (UCT) Dr Sheetal Silal to join an international taskforce of mathematical modellers to study the dynamics of a novel coronavirus outbreak in China. Little did she know the impact this would have on her life and career. 

Silal, an associate professor in the Department of Statistical Sciences at UCT and director of the Modelling and Simulation Hub, Africa (MASHA), is an expert in the development of mathematical models for predicting the dynamics of infectious diseases. This type of work has become a crucial part of evaluating the potential of control programmes to reduce morbidity and mortality, as well as supporting policy development around public health systems.

When she received the call from WHO’s head of emergency situations at the beginning of last year, the SARS-CoV-2 virus had only just started making global headlines. However, authorities were already concerned about it reaching pandemic proportions and the devastating effect this could have on lives and livelihoods everywhere.

Although Silal had spent the past 10 years doing mathematical modelling of infectious diseases, with particular focus on malaria, working on something of this magnitude was a first.

Inter-university collaboration

By the time the first COVID-19 cases were reported in South Africa early in March 2020, Silal had gained almost two months’ experience working with the international taskforce, placing her in a ready position to respond the South African National Treasury’s request to develop a mathematical model to investigate the dynamics of the local outbreak.


“We came together in an emergency situation and have since become a formidable team, applying for funding together to strengthen our collaboration.”

She and her team at MASHA joined forces with researchers from the South African DSI-NRF Centre for Epidemiological Modelling and Analysis at Stellenbosch University, the Health Economics and Epidemiology Research Office at the University of Witwatersrand and the National Institute for Communicable Diseases.

Together they formed the core modelling team of the South African COVID-19 Modelling Consortium. Ever since, they have been responsible for projecting the spread of the virus to support the South African government’s policy and planning. Among other things, the consortium created a COVID-19 dashboard alerting the public to infection rates and providing analyses of the various waves at a district and provincial level.

As the lead, Silal and the MASHA team are responsible for developing and running the models and hosting the dashboards, while all groups contribute to model conceptualisation and validation.

“It really is a very good example of inter-university collaboration,” says Silal. “Traditionally, we would be competitors for the same pots of research funding, but we came together in an emergency situation and have since become a formidable team, applying for funding together to strengthen our collaboration.”

Malaria research

In many ways, collaboration is the name of the game when it comes to mathematical modelling.

Prior to COVID-19, Silal’s work largely focused on developing models to track the successes and failures of, as well as the challenges facing, the fight against malaria in Africa.

“Though mathematical in theory, modelling is very much a multi-disciplinary process, because we need to have input from specialists in all areas of the malaria ecosystem, including clinicians, epidemiologists, pharmacologists, entomologists and so forth,” she explains.

Silal’s models synthesise this data to create a cohesive computer-based representation of malaria. Once that has been done, the models can be used to test the impact of interventions such as new drugs or prevention methods in silico, at no further cost.

In 2018, Silal was invited by the South African National Department of Health to develop a model to estimate the costs and benefits of achieving malaria elimination in the SA Malaria Elimination Investment Case.


“COVID-19 modelling consumed all my time last year. We have been, and are still working in panic mode without a chance to take a break.”

“We used the model to make a funding application to National Treasury and managed to secure ZAR319 million [about USD22 million] for malaria elimination,” recalls Silal.

Career highlights amid crisis

Her role in securing this funding is also, partly, what put Silal and her work on the map for the fight against COVID-19. Unsurprisingly, this has also come with its fair share of challenges.

As Silal points out: “COVID-19 modelling consumed all my time last year. We have been, and are still working in panic mode without a chance to take a break.”

Amid the challenges, however, the experience has also led to career highlights.

“For me, one of the biggest highlights was presenting to President Cyril Ramaphosa at the National Coronavirus Command Council,” she says. “It’s not often that researchers or scientists get to present directly to the president. So, I consider that a huge honour and privilege.”

Silal has also enjoyed the challenge of engaging with the public and the press.

Featured in Forbes Africa

As a result of her work, Silal was recently featured as one of the 10 women leading the charge against COVID-19 in Africa in a Forbes Africa cover story for International Women’s Day.  Although no stranger to interviews, this was the first time Silal had been featured in a publication not focused solely on academia or science. Despite the ups and downs of 2020, she feels that one of the silver-linings has been the opportunity to introduce mathematical modelling and its benefits to a wider audience.

“It’s been quite gratifying for us to witness the acceptance of modelling and modelling outcomes by policymakers in government and by the public as well,” she says.


“The ability to act fast and create new vaccines at a speed marks the start of a new era in global healthcare. This brings hope for combatting other deadly infectious diseases.”

Light at the end of the tunnel

It’s been more than a year since COVID-19 arrived on South African shores and a third wave of infections is looming.

Just like frontline healthcare workers, Silal and her team have been working nonstop. “We are very much in the burnout phase.”

Despite this, she sounds remarkably chipper and believes that there is light at the end of the tunnel, especially with the planned vaccine rollout and the building of population immunity.

“The ability to act fast and create new vaccines at a speed marks the start of a new era in global healthcare. This brings hope for combatting other deadly infectious diseases,” she adds.

“I think COVID-19 marked a paradigm shift in global consciousness. This new normal does require behaviour change, doing something differently from before, and the world will be in a better place because of it.”

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