South Africa’s daily coronavirus test positivity rate neared a record, rising above 30% on Saturday for the first time in almost five months as two sublineages of the omicron variant spread rapidly ahead of the nation’s winter season.

There were 8,524 new COVID-19 cases identified, representing a 31.1% positivity rate of those tested, the National Institute for Communicable Diseases said in a statement on its website. That’s the highest rate since the 32.2% recorded on Dec. 15, when a record 26,976 cases were recorded. The surge means South Africa is close to its highest positivity rate yet. The record so far was 34.9% on Dec. 14.

The positivity rate is taken as an indicator of how fast the disease is spreading through the community as many cases go undetected.

Still, only five deaths were recorded in the last 48 hours and just over 2,600 people are in the hospital with the disease. At the peak of the wave in mid-2021 when the delta variant was rampant, hundreds of people were perishing daily and hospitalizations peaked at about 16,000.

South Africa, which together with Botswana identified the omicron variant in November, was the first country to experience a wave driven by the strain and the way it played out was seen as an indication for what could happen elsewhere. Last month South African scientists identified two omicron sublineages, BA.4 and BA.5, and laboratory experiments have since shown that those strains can reinfect those who have already had the original omicron strain.

The current surge in infections and positivity shows that even though previous waves have been caused by the emergence of new variants the sublineages are now having the same effect, Tulio de Oliveira, who runs gene sequencing institutes in South Africa said on Twitter.