Live updates: follow the latest news on Covid-19 variant Omicron
Cases of Covid-19 are surging in South Africa as new infections doubled overnight and more people were admitted to the hospital.
The country reported 8,561 cases on Tuesday, up from 4,373 the previous day as the positivity rate soared to 16.5 per cent, from 10.2 per cent.
Last week only 3.6 per cent of tests were positive.
The rise in cases has worried officials despite doctors scientists from South Africa's National Institute for Communicable Diseases saying on Thursday that they believe Omicron infections are less severe.
Doctors have reported a similar trend however the institute is still trying to prove the theory and data will take time to gather and check given factors like the delay between infections and hospitalisations and that many infections have so far been in young, healthy people.
Only about 20 per cent of Covid-19 cases are severe, with about 80 per cent classed as either mild or asymptomatic.
One area of concern is whether antibodies from previous covid infections protect against the Omicron variant.
"Previous infection used to protect against Delta but now with Omicron that doesn't seem to be the case," said the institute's Prof Anne von Gottberg on Thursday during an online briefing organised by the World Health Organisation.
Vaccines should, however, still offer protection against severe disease, the experts said.
The institute warned that travel bans mean there are fewer flights that can bring in equipment and specialists and fly out specimens and samples, something that could hamper research and battling the new surge.
The WHO said it was deploying a surge team to help countries in southern Africa handle the latest wave.
Experts estimate somewhere between 65 per cent and 70 per cent of Gauteng, the centre of South Africa’s outbreak, has been infected with either the Delta or Beta strains.
“This variant certainly appears to skip over infection-acquired immunity without too much difficulty,” tweeted British immunologist Andrew Croxford.
“That’s my working hypothesis so far.”
Gauteng has recorded a steep rise in hospital admissions, with 674 last week, up from 286 in the seven days before.
It could surpass the figure this week, with 366 admissions so far and four days still left to report.
“New admissions increased by 144 per cent last week, or doubling about every six days,” Ridhwaan Suliman, a senior researcher at the Council for Scientific and Industrial Research in South Africa, tweeted on Wednesday.
“Remember: hospitalisations lag cases by one to three weeks, and with reporting delays, we need to wait a week to understand actual hospital admissions for the previous week.”
Children aged two and under make up the highest percentage of Covid-19 patients admitted to hospital in Gauteng in the final two weeks of November.
“When you look at the numbers of admissions by age, what we normally see is a large number of admissions in older people,” pubic health spokeswoman Dr Waasila Jassat said this week.
“But in this early resurgence in Tshwane, we are seeing most admissions in the 0-2 age group.
“And we are seeing a large number of admissions in the middle ages, sort of around 28 to 38.”
South Africa's National Institute for Communicable Diseases said on Thursday that there is anecdotal evidence more children are being admitted for treatment with the Omicron variant but that it requires more study to understand fully.
Prof Salim Abdool Karim, an epidemiologist in South Africa, said the country is currently seeing a “very rapid rise” in cases.
“Now this was anticipated because Omicron has mutations in it that will enable it to be more transmissible,” he told Times Radio in the UK.
“But we don’t really know how much more transmissible, and the early indications are that it seems to be tracking at about or just above the way in which Delta has spread.
“So when you take our case, if you take 10 days ago, we were at about 200 cases per day. Yesterday [it] was 8,000 cases.
“Now at that rate of increase and doubling time, that exceeds the doubling time of the Delta variant that we had in our third wave.
“So certainly, we know that the epidemiological evidence is confirming that the virus is highly transmissible, and the cases will rise quickly.”