While the Omicron variant is now the dominant strain of COVID-19 in South Africa, findings are showing that it is less severe, with fewer hospitalisations compared to the previous waves.
The National Institute of Communicable Diseases (NICD) revealed this during a media briefing on Wednesday.
According to the NICD’s Professor Cheryl Cohen, Omicron patients had an 80% lower chance of hospital admission.
“However, when we compare Omicron to the Delta in the previous waves, amongst hospitalised people, [it] was significantly 70% less in severity. So all the data together are pointing to a very consistent predictor picture of a reduction in severity in South Africa.”
However, according to Cohen, who is the Head of the Centre for Respiratory Diseases and Meningitis, researchers cannot yet tell how much it is from vaccination, previous infection or intrinsic reduced virulence of the virus.
“We still need to explain that. But I think what we can say is that in South Africa, this is the epidemiology. Omicron is behaving in a way that is less severe and likely this is generalisable to other countries in the region in sub-Saharan Africa, which have a similar picture, with very high levels of previous infections,” she explained.
In addition, the Professor said it was still unclear whether the picture will be similar in countries where there are high levels of vaccination but very low infection.
Following the emergence of Omicron, the NICD compared the severity of these infections to the Delta variant using S gene target failure (SGTF) as a proxy for Omicron.
The severity of SARS-CoV-2 was tested by comparing the proxy for Omicron, SGTF infections to non-SGTF (non-Omicron) infections diagnosed between 1 October and 30 November 2021.
This comparison revealed that 2.5% of those with SGTF infection were admitted to hospital compared to 12.8% of those with non-SGTF infection.
A comparison was made between Delta variant infections from April to November 2021, to SGTF infections diagnosed between 1 October and 30 November 2021.
“In short, the data suggest that individuals infected with Omicron may have a higher viral load, which could make them more infectious to others,” said Cohen.
Meanwhile, NICD’s Dr Michelle Groome, said there has been a decrease in daily case numbers and percentage of people testing positive in Gauteng.
In addition, infections are dropping in Limpopo, North West and Mpumalanga.
While hospitalisations have increased in Gauteng, Mpumalanga and the North West, the NICD said there are signals towards decreased severity in adults and a shorter length of stay.
Regardless of variant, Groome has called on people to continue to vaccinate, wear masks, social distance and limit large gatherings.