Omicron variant likely to cause more infections than Delta, severity of infection still unknown: Report

"We thought what will outcompete Delta? That has always been the question, in terms of transmissibility at least, ... perhaps this particular variant is the variant," Adrian Puren, acting executive director of South Africa's National Institute for Communicable Diseases (NICD), told Reuters in an interview.

The World Health Organization has already said it carries a high risk of infection surges.

If Omicron proves to be more transmissible than Delta, there could be a sharp rise in infections and once again overwhelm the healthcare system.

Puren said scientists should know within four weeks to what extent Omicron can evade the immunity generated by vaccines or prior infection, and whether it leads to worse clinical symptoms than other variants.

The report said that anecdotal accounts by doctors who have treated Covid-19 patients in South Africa say Omicron appears to be producing mild symptoms, including a dry cough, fever and night sweats, but experts have cautioned against drawing firm conclusions.

Puren said it was too early to say whether Omicron was displacing Delta as local scientists have only produced 87 sequences of Omicron so far.

With the rapid rise in cases, especially in thickly populated Gauteng province, it is likely that some replacement has already taken place, the report said.

After a third wave linked to the Delta strain of coronavirus, South Africa is bracing to tackle a likely fourth wave triggered by Omicron with daily infections seen topping 10,000 by the end of the week from around 2,270 on Monday.