JOHANNESBURG (Reuters) - South Africa may be entering a fifth COVID wave earlier than expected after a sustained rise in infections over the past 14 days that seems to be driven by the BA.4 and BA.5 Omicron sublineages, health officials and scientists said on Friday.
The country that has recorded the most coronavirus cases and deaths on the African continent only exited a fourth wave around January and had predicted a fifth wave could start in May or June, early in the southern hemisphere winter.
Health Minister Joe Phaahla told a briefing that although hospitalisations were picking up there was so far no dramatic change in admissions to intensive care units or deaths.
He said at this stage health authorities had not been alerted to any new variant, other than changes to the dominant circulating variant, Omicron, represented by the "BA" sublineages.
In a preprint published this week, South African researchers report that the spike proteins of BA.4 and BA.5 are identical to each other, and differ from the Omicron BA.2 sublineage by four mutations. Together, BA.4 and BA.5 had begun displacing BA.2 by early April, at which point they made up 50% of samples.
Infectious disease specialist Richard Lessells told the same briefing that waning immunity from previous waves could be contributing to the earlier-than-expected resurgence in cases.
