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Covid-19
Omicron is already dominant in South Africa
The variant appears to have rapidly outcompeted Delta and set off another wave of infections
JUST ONE month ago, South Africa’s pandemic appeared to be nearing an end. The country was recording fewer covid-19 cases—and admitting fewer patients to hospitals—than at any point since the beginning of the pandemic. No longer. Daily diagnosed cases of covid began rising in the middle of November. Shortly thereafter, hospital admissions started to tick up, too. The cause seems clear: Omicron, a mutation first discovered in samples collected on November 8th.
Analysing the shifting shares of different variants among sequenced viruses, Tom Wenseleers, a professor of biology and biostatistics at KU Leuven, in Belgium, found that Omicron probably overtook Delta in its share of South African cases as early as November 11th. This was just four weeks after the sequencing data suggests the virus started circulating. As of December 7th the total probable number of Omicron cases had reached 88,306. Modelling of past waves suggests confirmed cases represent roughly one in ten infections in South Africa. This implies that total Omicron infections are not in the hundreds, but in the hundreds of thousands.