FRIDAY, April 29, 2022 (HealthDay News) -- A new Omicron subvariant called BA.4 appears to be driving a sharp rise in COVID-19 cases in South Africa, health experts say.
The number of daily cases reported by the country has shot up from just a few hundred a few weeks ago to just over 6,000, and the rate of positive tests has jumped from 4% in mid-April to 19% as of Thursday, according to the Associated Press.
Increases in coronavirus spread have also been detected in wastewater surveillance.
Despite the surge in cases, there has been only a slight bump in COVID-19 hospitalizations and no increase in deaths, stressed Salim Abdool Karim, a public health expert at the University of KwaZulu-Natal who previously advised the South Africa government on its COVID-19 response.
It appears the BA.4 subvariant is quickly pushing aside the original Omicron variant and other versions of the coronavirus, but "it's too early to tell whether BA.4 is going to cause a fully-fledged wave," Abdool Karim said, the AP reported.
There is one concerning trend involving the new subvariant, however: Children infected with it are the first to be ending up in hospitals, echoing what happened during the first Omicron surge, said Helen Rees, executive director of the Reproductive Health and HIV Institute at the University of Witwatersrand in Johannesburg.
The original Omicron variant first appeared in November in South Africa and Botswana before spreading worldwide.
BA.4 appears more transmissible than both the original Omicron variant and an Omicron subvariant called BA.2, experts say. However, the World Health Organization recently said that BA.4 doesn't seem to cause more severe illness than other versions of the coronavirus, the AP reported.
BA.4 has been detected in other countries, but it's not clear whether "it's going to become a globally dominant variant," Abdool Karim said.
The new Omicron subvariant isn't yet an issue in the United States, where the Omicron subvariant BA.2 is the dominant strain, and a descendant called BA.2.12.1 that's believed to spread faster than previous versions of the coronavirus is becoming more common, the AP reported.
Last week, BA.2.12.1 caused about 29% of COVID-19 cases in the United States, according to the U.S. Centers for Disease Control and Prevention.
Find out more about the COVID-19 Omicron variant at the CDC.
SOURCE: Associated Press