Third Covid-19 wave full of unknowns, but more than 70,000 could die

SA’s third wave of Covid-19 could see more than 70,000 deaths if there is a “slow, weak, response” to its inception, but about 7,800 if the response is “fast and strong”.

These figures, which include Covid-19 deaths in and out of hospital, are according to the latest model by the South African Covid-19 Modelling Consortium. They were released by the National Institute for Communicable Diseases (NICD).

The researchers said the modelled scenarios “do not yet include the impact of vaccination and do not estimate the timing of a third wave”. There is “substantial uncertainty” about if and when a new variant might emerge, and changes in population behaviour “remain unpredictable”.

Looking at Covid-19 deaths in hospital (and thus not including excess deaths, 85% of which are assumed to be due to Covid-19), the modellers predict 40,000 will die in a third wave if the response is slow and weak, but if fast and strong the number will be 4,600.

In the second wave the country saw 34,300 Covid-19 deaths in hospital and 18,600 in the first wave.

In general, the researchers said, the third wave will not exceed the second wave, unless a new variant appears.

“The emergence of a highly transmissible new variant may result in a third wave of the same size as the second wave — or worse, especially if the variant provides an opportunity for immune escape,” they said.  

The most likely drivers of a third wave would be people relaxing their behaviour after the end of the second wave, ongoing viral mutation, seasonal factors and reinfection due to the waning of immunity conveyed by previous infection, they added. 

As SA heads into winter transmission could increase due to more people being indoors, decreased ventilation and “increased susceptibility to respiratory infections”.

In the early phases of the pandemic these factors were not yet clearly understood.

According to Wits university vaccinology expert Prof Shabir Madhi, variables make the third wave difficult to predict, but what is certain is that Covid-19 is not going away.

According to Wits university vaccinology expert Prof Shabir Madhi, variables make the third wave difficult to predict, but what is certain is that Covid-19 is not going away.

This because it is an airborne disease, he said.

“It came as a real blow to the entire control system when we realised that contaminated surfaces and direct infection are not the biggest problems.”

Because it is a “truly respiratory pathogen”, it is impossible to totally contain it.

“Anyone who understands respiratory viruses will know that unlike other viruses that are not airborne, it is going to spread quickly, and once it seeds widely, it’s impossible that it is just going to disappear,” he said.

The researchers generated a spectrum of five possible scenarios based on differences in adherence or non-adherence to non-pharmaceutical interventions (such as mask-wearing, social distancing and hand hygiene) and government restrictions.

They said “across scenarios”, in the absence of a new variant, the peak of the third wave would likely be lower than the second.

However, “a slow, weak behavioural response increases admissions for severe or critical cases across most groups”.

Across provinces there is likely to be notable variation, with Gauteng likely to be hardest hit across the potential scenarios that could unfold.

This is due to the “higher concentration of working-age adults and people with comorbidities in the province, and the lower estimates of seroprevalence”.

In all provinces the time “from initial increase in transmission to the peak is, on average, two to three months”, but this could change depending on several factors.

The model projections will be updated as new data becomes available, according to the researchers.