Fourth wave modelling to help inform new lockdown restrictions: advisor

 ·23 Nov 2021

Professor Bruce Mellado, a member of Gauteng’s Covid-19 Advisory Committee, says the province is busy preparing models for a potential fourth wave of Covid-19 infections.

Mellado told radio station 702 that the province reported a 300% rise in cases over the last week, much higher than expected given the history of the pandemic. He added that the province was now awaiting further data, independent from what had already been received, to help calibrate models and give an idea of what to expect in the coming weeks and months.

“This is crucial as we need to understand what levels of restrictions we are going to need during the fourth wave. They are going to be different (from the third wave) – but how different will depend a lot on how we understand the data now.”

Mellado said that this modelling was essential to help prepare medical professionals and government and inform policy decision-makers, such as hospital CEOs, over the December period.

“We really need to get now, based on the data which is the most accurate we can use, where we are going to be in a few weeks now. Those numbers are going to be absolutely critical for policymakers on the ground to make preparations – like for the third wave.”

On Monday (22 November), the National Institute for Communicable Diseases (NICD) reported an increase in the 7-day moving average for new Covid-19 cases and the percentage testing positive in Gauteng, particularly in Tshwane amongst 10 – 29-year-olds over the past week.

Additionally, the NICD has recently identified a cluster among the 20 – 44 age group at an institute of higher education in Tshwane.

“We are monitoring these trends to see if these increases persist. Localised increases in case numbers (clusters) are not unexpected. However, it is hard to say whether the increases indicate the start of a widespread resurgence,” said NICD acting executive director Professor Adrian Puren.

Previous waves have been driven to a large extent by the emergence of new SARS-CoV-2 variants, Beta in the second wave and Delta in the third wave.

“Genomic sequencing in South Africa has, to date, not yet detected the emergence of any new variants which are making up an increasing proportion of the sequences,” Puren said.

“Regardless of potential new variants in the future, the importance of non-pharmaceutical interventions remains unchanged, and individuals are encouraged to wear masks, practice hand hygiene, maintain social distancing and to gather in well-ventilated spaces.”

The Department of Health reports that 41% of adults in South Africa have received at least one dose of a Covid-19 vaccine, with 35% fully vaccinated.

“It is difficult to predict the magnitude and timing of a potential Covid-19 resurgence, however, we implore the unvaccinated to get the Covid-19 vaccine, especially the elderly and those with comorbidities,” said the head of the division of Public Health Surveillance and Response, Dr Michelle Groome.

She added that vaccination and prior infection provide good protection against developing severe disease, and while there might be an increase in future case numbers, the number of hospitalisations and deaths are expected to be less severe in comparison to the previous resurgence.

“As the endemic endures, I would like to reassure the public that the NICD continues to acutely monitor trends in case numbers, positivity rates and hospitalisations,” Puren said.

Read: South Africa fourth wave predicted as Covid-19 cases rise

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