Here’s what you need to know about the BA.2.12.1, BA.4 and BA.5 Omicron strains.WHAT IS THE BA.2.12.1 OMICRON STRAIN?The BA.2.12.1 strain is a sub-lineage of the BA.2 Omicron variant, which continues to be the dominant strain in Australia. The new BA.2.12.1 has been detected in North America and Europe. Early evidence suggests it is more transmissible than BA.2 but does not cause more severe disease.WHERE HAS BA.2.12.1 BEEN FOUND IN AUSTRALIA? Victoria’s’s Department of Health department has confirmed that the BA.2.12.1 Omicron strain has been detected in a south-east metropolitan Melbourne wastewater catchment.WHAT ABOUT BA.4 and BA.5?One case of the BA.4 and one case of the BA.5 variant have been detected in South Australia, both from international travellers, SA Health announced in a late night statement on Monday It is the first time the variants have been detected here, but the statement said it was not unexpected to see new variants due to international borders being open.NED-3952-Covid-19-Variants“These variants have also been recently detected interstate,” the statement said.The BA.4 and BA.5 sub-variants are descendant lineages of the already transmissible Omicron strain of Covid.ARE THE NEW STRAINS MORE TRANSMISSIBLE? Victoria’s Health Department says early evidence suggests BA2.12.1 is more transmissible than BA.2, but does not cause more severe disease.Cases of BA.2.12.1 are rising across the US, with experts warning it soon become the dominant strain across the country. Current estimates suggest that BA.2 variants have replication rates at least 30 per cent greater than BA.1 variants, Forbes magazine reports. Alex Sigal, a professor at the Africa Health Research Institute in South Africa, told Fortune magazine that BA.4 and BA.5 appear to be more transmissible than “stealth Omicron” and have the ability to evade antibodies from vaccination and prior infection.WILL THE NEW VARIANTS LEAD TO MORE HOSPITALISATIONS?Professor Adrian Esterman, of the University of South Australia, has warned that the new variants will “inevitably” lead to more hospitalisations and cases of long Covid. “Omicron BA.4 has just been found in a traveller returning from South Africa to NSW,” he tweeted on Friday. “BA.4 is dominating in South Africa, and has an R0 of about 15, similar to measles, our most contagious disease.“The subvariant BA2.12.1 also has an R0 of 15, and is taking over in the USA.“BA.2.12.1 now accounts for 25 per cent of cases in the USA. BA.4 is rapidly becoming the dominant strain in South Africa. “Increasing case numbers will inevitably result in increasing hospitalisations and more people with long-Covid. This is real and happening now.”
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