Health experts across the globe are monitoring a spike in COVID-19 cases in South Africa driven by the omicron "sister variants" BA.4 and BA.5, The New York Times reported May 2.
Hospitalizations are rising in the country and cases have tripled in the past week, suggesting the country may be staring down a fifth COVID-19 surge.
About 90 percent of people in South Africa have some immunity against the virus, mainly from previous infections, as the country saw a large surge this winter from the original omicron strain BA.1. Emerging data suggests BA.4 and BA.5 — first identified in South Africa earlier this year — evade natural immunity in unvaccinated people infected by BA.1.
"That is the reason why it is starting to fuel a wave in South Africa," Tulio de Oliveira, PhD, director of South Africa's KwaZulu-Natal Research and Innovation Sequencing Platform, told the Times.
While BA.1 originated in South Africa and quickly gained dominance worldwide, experts say it's hard to predict whether BA.4 and BA.5 could also surge in other parts of the world. Scientists are also still assessing whether they cause more severe illness.
View the full report here.