The number of new positive cases of COVID-19 reported in South Africa has continued its downward trend despite increased testing, according to South African National Institute of Communicable Diseases (NICD) data.
The NICD reported 17,154 new cases on Dec. 11, nearly 2,000 down from the 19,018 new cases reported on Dec. 10. At the same time the NICD recorded 104,831 new tests conducted on Dec. 11, which was over 20,000 more carried out than on Dec. 10.
Professor Francois Balloux, director of the University College London Genetics Institute, noted a “dramatic decrease in test positivity,” which fell from 45 percent on Dec. 10 to 28 percent from Dec. 11.
“The Omicron outbreak in SA [South Africa] with its extraordinary fast rise, and apparently nearly equally fast fall, is one of the most mind-boggling things I’ve ever seen during my career as an infectious disease epidemiologist,” Balloux stated on Twitter.
While the number of daily hospital admissions saw an upward trend from 374 new admissions on Dec. 8 to 507 new admissions on Dec. 10, it dropped to 184 new admissions on Dec. 11.
The current trend appears to vary from that projected by a pre-print study in the UK that sets out to model the effects of the Omicron variant in England.
Assuming the most ideal conditions (low immune escape of Omicron and high booster efficacy), researchers projected an infection leading to a peak of 2,000 daily hospital admissions with 175,000 hospitalizations and 24,700 deaths between Dec. 1, 2021 and April 30, 2022 if England sticks with its current “Plan B” policy, according to the study conducted by the London School of Hygiene and Tropical Medicine (LSHTM).
However, Rosanna Barnard who co-led the research, acknowledged that “there is a lot of uncertainty about the characteristics of Omicron, and whether Omicron in England will follow the same course as it has in South Africa,” according to a LSHTM news release.
“In our most optimistic scenario, the impact of Omicron in the early part of 2022 would be reduced with mild control measures such as working from home,” Barnard added.
She then pointed out that in the worst case scenario, “mask-wearing, social distancing, and booster jabs are vital, but may not be enough.”
Regarding these projections produced by models, University of East Anglia medicine professor Paul Hunter told The Independent on Dec. 11 that any model “is only as good as its assumptions.”
Hunter said that the UK study assumed that the severity of disease outcomes for Omicron was identical for Delta in the unvaccinated.
“Although we will not know for certain for a few weeks, indications from South Africa do suggest that Omicron does cause less severe disease than Delta, though this is likely to be due to partial immunity,” Hunter said.
“There is early as yet not peer reviewed data suggesting that although Omicron mutations are enough to escape antibody, T-cell immunity would be less compromised,” Hunter added.