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HomeSouth AfricaFormer head of NICD says SA's COVID-19 modelling 'flawed and illogical'

Former head of NICD says SA's COVID-19 modelling 'flawed and illogical'

The modelling of how many people would contract COVID-19 and die was “flawed and illogical and made wild assumptions”. The Financial Mail reports that this is according to Professor Shabhir Madhi, the former head of South Africa’s National Institute for Communicable Diseases (NICD) who says the initial modelling and fatality estimates were “back-of-envelope calculations”

The report says this is an important claim not just because of Madhi’s stature (he also co-ran the SA Medical Research Council), but also because the COVID-19 model, which suggested between 87,000 and 350,000 deaths, was instrumental in the government’s decision to implement a lockdown

The government’s initial model also predicted that 600 COVID-19 patients would need treatment in intensive care units (ICU) in South Africa by 1 April 1. But by 18 April, there were 32 COVID-19 patients in ICU. The report says while the lockdown would have slowed the spread of the disease, it had only been in place for four days by 1 April, so this was likely not the reason why there were so few ICU patients.

The models were prepared by the SA Centre for Epidemiological Modelling & Analysis (Sacema) at Stellenbosch University, as well as the NICD. They used data from Wuhan, the Chinese city where the outbreak began. The Sacema model modelled its fatality projections around different scenarios in which 10%, 20% and 40% of the population contracted the virus. Madhi claims the model was not sufficiently flexible to adjust for infection rates, depending on how many other people in the population had contracted the virus. As it is, the more people who are infected, the fewer new people a contagious person can potentially affect.

The report says when asked why their model was based on a minimum 10% infection rate, and whether they still believed deaths would be as high as initially predicted, Professor Juliet Pulliam, the head of Sacema, said: “The model you refer to was a preliminary assessment that was based on the best available information at the time. A new modelling report will be released by the NICD (this week).”

The report says in its defence, Sacema’s model isn’t the only one to be adjusted downwards. The UK’s Imperial College London initially predicted huge numbers of deaths, including 2.2m in the US, but this has since been toned down.

Madhi also warns that no-one is modelling the “collateral damage” of the lockdown, and the impact of the economic meltdown on disease and death. He says the government’s focus is on decreasing infections and fatalities rather than the broader picture. The report says at this point, the economic impact is unclear. Neither economists nor business leaders have provided any estimates of “life years lost” because of the increase in unemployment.

[link url="https://www.businesslive.co.za/fm/features/2020-04-24-sas-covid-19-models-were-flawed-says-former-nicd-expert/"]Full Financial Mail report[/link]

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