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 sub-variants, health officials and scientists have said.

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, Reuters reported.

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.

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.