JOHANNESBURG, Dec 10 (Reuters) - South African scientists see no sign that the Omicron coronavirus variant is causing more severe illness, they said on Friday, as officials announced plans to roll out vaccine boosters with daily infections approaching an all-time high. South Africa alerted the world to Omicron late last month, prompting alarm that the highly mutated variant could trigger a new surge in global infections. Hospital data show that COVID-19 admissions are now rising sharply in more than half of the country"s nine provinces, but deaths are not rising as dramatically and indicators such as the median length of hospital stay are reassuring. Although scientists say more time is needed to arrive at a definitive conclusion, Health Minister Joe Phaahla said the signs on severity were positive. "Preliminary data does suggest that while there is increasing rate of hospitalisation ... it looks like it is purely because of the numbers rather than as a result of any severity of the variant itself, this Omicron," he said. In the past few days, a nationwide outbreak linked to variant has been infecting around 20,000 people a day, with 19,018 new COVID-19 cases on Thursday, according to data from the National Institute of Communicable Disease, but only 20 new deaths. Infections have yet to reach the peak of more than 26,000 daily cases during a third wave fuelled by the Delta variant. read more South Africa has fully vaccinated about 38% of adults, more than in many other African countries but well short of the government"s year-end target. It recently delayed some vaccine deliveries due to oversupply as the pace of inoculations slowed. read more A healthcare worker prepares a dose of the Pfizer coronavirus disease (COVID-19) vaccine, amidst the spread of the SARS-CoV-2 variant Omicron, in Johannesburg, South Africa, December 9, 2021. REUTERS/ Sumaya Hisham Healthcare workers assist patients being treated at a makeshift hospital run by charity organisation The Gift of the Givers, during the coronavirus disease (COVID-19) outbreak in Johannesburg, South Africa, July 11, 2021. Picture taken July 11, 2021. REUTERS/ Sumaya Hisham Healthcare workers assist a patient being treated at a makeshift hospital run by charity organisation The Gift of the Givers, during the coronavirus disease (COVID-19) outbreak in Johannesburg, South Africa, July 10, 2021. REUTERS/ Sumaya Hisham 1/4 Healthcare workers assist patients being treated at a makeshift hospital run by charity organisation The Gift of the Givers, during the coronavirus disease (COVID-19) outbreak in Johannesburg, South Africa, July 11, 2021. Picture taken July 11, 2021. REUTERS/ Sumaya Hisham Read More BOOSTERS COMING Health department deputy director-general Nicholas Crisp said on Friday that boosters of Pfizer-BioNTech"s vaccine (PFE.N), (22UAy.DE) would be available to people six months after they had received their second dose, with the first people becoming eligible late this month. Johnson & Johnson (JNJ.N) boosters, already available to health workers in a research study, would be rolled out to others soon, he said. Crisp denied that offering boosters was a means of using up vaccine stock. "We do not need to consume vaccines. They are expensive and we will only use vaccines if there is evidence to do so," he said. The World Health Organization recommended this week that boosters should be given to people who are immunocompromised or had received an inactivated COVID-19 vaccine to protect against waning immunity. But it has said previously that administering primary doses should be the priority given that vaccination rates remain worryingly low in many developing countries. read more A small study from a South African research institute this week suggested that Omicron could partially evade protection from two doses of the Pfizer vaccine, but the company and its partner, BioNTech, say a three-shot course of their vaccine can neutralise Omicron in the laboratory. read more Glenda Gray, president of the South African Medical Research Council, said there were far more unvaccinated people among South Africa"s hospital admissions and the evidence was that the Pfizer vaccine was still offering protection. "We are seeing that this vaccine is maintaining effectiveness. It may be slightly reduced, but we are seeing effectiveness being maintained for hospital admissions and that is very encouraging," she said. Additional reporting by Tim Cocks in Johannesburg; Editing by David Goodman, Robert Birsel and Alex Richardson