An increasing share of South Africa’s Covid-19 cases are the BA.4 and BA.5 sub-lineages of the Omicron variant, suggesting those might have a growth advantage over others, Prof Helen Rees said on Thursday.
Rees added at a World Health Organisation news conference that despite rising Covid-19 infections, SA was so far not seeing a huge increase in mortality or intensive care admissions.
The WHO said earlier that Africa is seeing an uptick in Covid-19 cases largely driven by a doubling in cases reported in SA.
There’s also a new preprint from South Africa researchers at CERI too: “Continued Emergence and Evolution of Omicron in South Africa: New BA.4 and BA.5 lineages”:
“..the continued discovery of genetically diverse Omicron lineages shifts the level of support for hypotheses regarding their origin, from an unsampled location to a discrete reservoir, such as human chronic infections (or even a network of chronic human infections) and/or animal reservoirs, potentially contributing to further evolution and dispersal of the virus. We are actively investigating the potential of a yet unidentified animal reservoir in the region..”
Pre-print Out – Continued Emergence and Evolution of Omicron in South Africa: New BA.4 & BA.5 lineages – https://t.co/llcagIwEtI – In this thread, we explain the origin, evolution, and epidemiology of the new Omicron lineages causing the increase of infections in SA. pic.twitter.com/fbMxH61OpB
Summary of what we know about Omicron BA.4 & BA.5:
– Suggesting a discrete reservoir, such as chronic human infections and/or animal reservoirs
– BA.4 and BA.5 have a growth advantage over BA.2
– Escape BA.1 infection & potential new wave
A good thread from German virologist Christian Drosten about BA.4 and BA.5 here (in German):
Nach dem vielen Nonsens, der hier in den vergangenen Wochen verbreitet wurde, möchte ich mal wieder ein paar Informationen zu SARS-CoV-2 geben. Derzeit werden in der SARS2-Überwachung drei neue Varianten beobachtet. 1. Omikron BA.4 und BA.5 (1/9)
The Sigall Lab have been doing some research on the immunity gained from infection by BA.1 against reinfection by BA.4 and BA.5. It’s not good news:
We measured immunity against the #Omicron BA.4 and BA.5 variants by people infected with the original (BA.1) Omicron sub-lineage. Results consistent with these variants forming next infection wave.
South Africa is currently seeing an increase in Covid cases associated with BA.4 and BA.5:
There has been an uptick in hospitalizations recently too:
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 said on Friday.
