By Alexander Winning and Wendell Roelf
JOHANNESBURG (Reuters) -South Africa's daily COVID-19 infection rate could triple to more than 10,000 by the end of this week as the new Omicron variant spreads rapidly, an infectious disease expert said on Monday.
Professor Salim Abdool Karim, the government's chief adviser during the initial response to the pandemic, also said that, while existing vaccines should be effective at preventing severe disease from the variant, South African hospitals could be under pressure from a flood of admissions within two to three weeks.
"Even if Omicron is not clinically worse, and certainly the anecdotes don't raise any red flags just yet... we are going to see this (pressure on hospitals) in all likelihood because of the rapidity of transmission," he told a news conference.
The discovery of the variant in southern Africa has caused global alarm, with countries limiting travel from the region and imposing other restrictions for fear it could spread quickly even in vaccinated populations.
The World Health Organization said on Monday that the variant posed a very high global risk of infection surges, though further research was needed to assess its potential to evade protection against immunity induced by vaccines and previous infections.
Abdool Karim, a professor at South Africa's University of KwaZulu-Natal and Columbia University in the United States, said vaccines were still likely to confer good protection against Omicron because of T-cell immunity, different from the antibody immunity that often blocks infections.
"Even if there's some escape from antibodies it's very hard to escape T-cell immunity", he said.
Doctors who have treated South African COVID-19 patients say Omicron so far appears to be producing mild symptoms, including a dry cough, fever and night sweats. But public health experts say it is too early to draw firm conclusions.
The government says it is doing everything possible to prepare health facilities to cope with the variant and is asking countries that imposed travel restrictions on southern Africa to reverse them, Health Minister Joe Phaahla told the same news conference.
So far, there has not been a steep increase in hospital admissions or COVID-19 deaths since the variant was first detected in South Africa last week, in samples from earlier in November.
On Sunday, the National Institute for Communicable Diseases reported 2,858 new cases, down from 3,220 on Saturday but compared to roughly 300 two weeks ago when the country, where around 35% of adults have been fully vaccinated against COVID-19, was experiencing a lull after a third wave of infections.
South Africa has confirmed close to 3 million COVID-19 infections in total during the pandemic and over 89,000 deaths, the most on the African continent.
President Cyril Ramaphosa said on Sunday that authorities were considering making vaccination compulsory for certain places and activities - a departure from an earlier stance that it would remain voluntary.
Big business came out strongly in support on Monday, with one association saying it fully endorsed the proposal and another seeking a legal opinion to help companies enforce it.
Renai Moothilal, head of a group representing auto component manufacturers, said his industry was supportive in principle of mandatory vaccination because lower car assembly volumes had put component-makers under pressure and business continuity was important.
But a lobby group mainly representing the interests of white Afrikaans-speakers, descendants of predominantly Dutch settlers, wrote to Ramaphosa saying while it supported people getting immunised voluntarily, vaccine mandates were an "unjustifiable violation of personal freedoms" that risked a backlash.
(Additional reporting by Promit Mukherjee, Emma Rumney and Nqobile Dludla in Johannesburg; Writing by Peter Graff and Alexander Winning; Editing by John Stonestreet and Angus MacSwan)